OKHttp使用简介

现在android网络方面的第三方库很多，volley，Retrofit，OKHttp等，各有各自的特点，这边博客就来简单介绍下如何使用OKHttp。

梗概

OKHttp是一款高效的HTTP客户端，支持连接同一地址的链接共享同一个socket，通过连接池来减小响应延迟，还有透明的GZIP压缩，请求缓存等优势OKHttp官网

配置环境

支持Android 2.3及其以上版本，要求java JDK1.7以上

jar包引入

可以通过下载jar包直接导入工程地址如下下载地址

或者通过构建的方式导入

MAVEN：

<code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>com.squareup.okhttp<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>okhttp<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>2.4.0<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

GRADLE

<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">compile <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'com.squareup.okhttp:okhttp:2.4.0'</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

用法

在向网络发起请求的时候，我们最常用的就是GET和POST，下面就来看看如何使用

1. GET

在OKHttp，每次网络请求就是一个Request，我们在Request里填写我们需要的url，header等其他参数，再通过Request构造出Call，Call内部去请求参数，得到回复，并将结果告诉调用者。

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.jackchan.test.okhttptest;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.os.Bundle;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.support.v7.app.ActionBarActivity;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.util.Log;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.squareup.okhttp.Cache;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.squareup.okhttp.Callback;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.squareup.okhttp.OkHttpClient;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.squareup.okhttp.Request;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.squareup.okhttp.Response;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.IOException;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">TestActivity</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ActionBarActivity</span> {</span>

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> String TAG = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"TestActivity"</span>;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> OkHttpClient client = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> OkHttpClient();

<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">protected</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onCreate</span>(Bundle savedInstanceState) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Thread(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Runnable() {
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
execute();
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (Exception e) {
e.printStackTrace();
}
}
}).start();
}

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">execute</span>() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> Exception {
Request request = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Request.Builder()
.url(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://publicobject.com/helloworld.txt"</span>)
.build();
Response response = client.newCall(request).execute();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(response.isSuccessful()){
System.out.println(response.code());
System.out.println(response.body().string());
}
}
}
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li></ul>

我们通过Request.Builder传入url，然后直接execute执行得到Response，通过Response可以得到code,message等信息。

这个是通过同步的方式去操作网络请求，而android本身是不允许在UI线程做网络请求操作的，因此我们需要自己开启一个线程。

当然，OKHttp也支持异步线程并且有回调返回，有了上面同步的基础，异步只要稍加改动即可

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">enqueue</span>(){
Request request = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Request.Builder()
.url(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://publicobject.com/helloworld.txt"</span>)
.build();
client.newCall(request).enqueue(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Callback() {
@Override
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onFailure</span>(Request request, IOException e) {

}

@Override
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onResponse</span>(Response response) throws IOException {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//NOT UI Thread</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(response.isSuccessful()){
System.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">out</span>.println(response.code());
System.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">out</span>.println(response.body().<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">string</span>());
}
}
});
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul>

就是在同步的基础上讲execute改成enqueue，并且传入回调接口，但接口回调回来的代码是在非UI线程的，因此如果有更新UI的操作记得用Handler或者其他方式。

2、POST

说完GET该介绍些如何使用POST，POST情况下我们一般需要传入参数，甚至一些header，传入参数或者header

比如传入header

Request request = new Request.Builder()

.url("https://api.github.com/repos/square/okhttp/issues")

.header("User-Agent", "OkHttp Headers.java")

.addHeader("Accept", "application/json; q=0.5")

.addHeader("Accept", "application/vnd.github.v3+json")

.build();

传入POST参数

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">RequestBody formBody = new FormEncodingBuilder()
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.add</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"platform"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"android"</span>)
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.add</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"name"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"bug"</span>)
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.add</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"subject"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"XXXXXXXXXXXXXXX"</span>)
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.build</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

Request request = new Request<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Builder</span>()
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.url</span>(url)
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.post</span>(body)
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.build</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li></ul>

可以看出来，传入header或者post参数都是传到Request里面，因此最后的调用方式也和GET方式一样

<code class="hljs vbscript has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">Response</span> <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">response</span> = client.newCall(<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">request</span>).<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">execute</span>();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">response</span>.isSuccessful()) {
return <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">response</span>.body().<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span>();
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
throw <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> IOException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Unexpected code "</span> + <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">response</span>);
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

这个代码是同步网络请求，异步就改成enqueue就行了。

请求缓存

在网络请求中，缓存技术是一项应用比较广泛的技术，需要对请求过的网络资源进行缓存，而okhttp也支持这一技术，也使用十分方便，前文涨经常出现的OkHttpclient这个时候就要派送用场了。看下面代码

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">package <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.jackchan</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.test</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.okhttptest</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

import android<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.os</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Bundle</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import android<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.support</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.v</span>7<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.app</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ActionBarActivity</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import android<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.util</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Log</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

import <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.squareup</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.okhttp</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Cache</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.squareup</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.okhttp</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.CacheControl</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.squareup</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.okhttp</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Call</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.squareup</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.okhttp</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Callback</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.squareup</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.okhttp</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.OkHttpClient</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.squareup</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.okhttp</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Request</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.squareup</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.okhttp</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Response</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

import java<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.io</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.File</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import java<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.io</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.IOException</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

public class TestActivity extends ActionBarActivity {

private final static String TAG = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"TestActivity"</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

private final OkHttpClient client = new OkHttpClient()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

@Override
protected void onCreate(Bundle savedInstanceState) {
super<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.onCreate</span>(savedInstanceState)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
setContentView(R<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.layout</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.activity</span>_test)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
File sdcache = getExternalCacheDir()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
int cacheSize = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1024</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1024</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">; // 10 MiB</span>
client<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.setCache</span>(new Cache(sdcache<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.getAbsoluteFile</span>(), cacheSize))<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
new Thread(new Runnable() {
@Override
public void run() {
try {
execute()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
} catch (Exception e) {
e<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.printStackTrace</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
}
}
})<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.start</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
}

public void execute() throws Exception {
Request request = new Request<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Builder</span>()
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.url</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://publicobject.com/helloworld.txt"</span>)
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.build</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

Response response1 = client<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newCall</span>(request)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.execute</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
if (!response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.isSuccessful</span>()) throw new IOException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Unexpected code "</span> + response1)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

String response1Body = response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.body</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.string</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 1 response:          "</span> + response1)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 1 cache response:    "</span> + response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cacheResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 1 network response:  "</span> + response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.networkResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

Response response2 = client<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newCall</span>(request)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.execute</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
if (!response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.isSuccessful</span>()) throw new IOException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Unexpected code "</span> + response2)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

String response2Body = response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.body</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.string</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 response:          "</span> + response2)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 cache response:    "</span> + response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cacheResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 network response:  "</span> + response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.networkResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 equals Response 1? "</span> + response1Body<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.equals</span>(response2Body))<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

}
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li><li style="box-sizing: border-box; padding: 0px 5px;">58</li><li style="box-sizing: border-box; padding: 0px 5px;">59</li><li style="box-sizing: border-box; padding: 0px 5px;">60</li><li style="box-sizing: border-box; padding: 0px 5px;">61</li><li style="box-sizing: border-box; padding: 0px 5px;">62</li><li style="box-sizing: border-box; padding: 0px 5px;">63</li><li style="box-sizing: border-box; padding: 0px 5px;">64</li><li style="box-sizing: border-box; padding: 0px 5px;">65</li><li style="box-sizing: border-box; padding: 0px 5px;">66</li><li style="box-sizing: border-box; padding: 0px 5px;">67</li><li style="box-sizing: border-box; padding: 0px 5px;">68</li></ul>

okhttpclient有点像Application的概念，统筹着整个okhttp的大功能，通过它设置缓存目录，我们执行上面的代码，得到的结果如下



response1 的结果在networkresponse，代表是从网络请求加载过来的，而response2的networkresponse 就为null，而cacheresponse有数据，因为我设置了缓存因此第二次请求时发现缓存里有就不再去走网络请求了。

但有时候即使在有缓存的情况下我们依然需要去后台请求最新的资源（比如资源更新了）这个时候可以使用强制走网络来要求必须请求网络数据

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"> public void execute() throws Exception {
Request request = new Request<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Builder</span>()
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.url</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://publicobject.com/helloworld.txt"</span>)
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.build</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

Response response1 = client<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newCall</span>(request)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.execute</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
if (!response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.isSuccessful</span>()) throw new IOException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Unexpected code "</span> + response1)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

String response1Body = response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.body</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.string</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 1 response:          "</span> + response1)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 1 cache response:    "</span> + response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cacheResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 1 network response:  "</span> + response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.networkResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

request = request<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newBuilder</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cacheControl</span>(CacheControl<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.FORCE</span>_NETWORK)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.build</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
Response response2 = client<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newCall</span>(request)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.execute</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
if (!response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.isSuccessful</span>()) throw new IOException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Unexpected code "</span> + response2)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

String response2Body = response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.body</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.string</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 response:          "</span> + response2)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 cache response:    "</span> + response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cacheResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 network response:  "</span> + response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.networkResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 equals Response 1? "</span> + response1Body<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.equals</span>(response2Body))<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li></ul>

上面的代码中

response2对应的request变成

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">request = request<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newBuilder</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cacheControl</span>(CacheControl<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.FORCE</span>_NETWORK)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.build</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

我们看看运行结果



response2的cache response为null，network response依然有数据。

同样的我们可以使用 FORCE_CACHE 强制只要使用缓存的数据，但如果请求必须从网络获取才有数据，但又使用了FORCE_CACHE 策略就会返回504错误，代码如下，我们去okhttpclient的缓存，并设置request为FORCE_CACHE

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">protected void onCreate(Bundle savedInstanceState) {
super<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.onCreate</span>(savedInstanceState)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
setContentView(R<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.layout</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.activity</span>_test)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
File sdcache = getExternalCacheDir()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
int cacheSize = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1024</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1024</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">; // 10 MiB</span>
//client<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.setCache</span>(new Cache(sdcache<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.getAbsoluteFile</span>(), cacheSize))<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
new Thread(new Runnable() {
@Override
public void run() {
try {
execute()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
} catch (Exception e) {
e<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.printStackTrace</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(e<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.getMessage</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.toString</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
}
}
})<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.start</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
}

public void execute() throws Exception {
Request request = new Request<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Builder</span>()
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.url</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://publicobject.com/helloworld.txt"</span>)
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.build</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

Response response1 = client<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newCall</span>(request)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.execute</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
if (!response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.isSuccessful</span>()) throw new IOException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Unexpected code "</span> + response1)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

String response1Body = response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.body</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.string</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 1 response:          "</span> + response1)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 1 cache response:    "</span> + response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cacheResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 1 network response:  "</span> + response1<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.networkResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

request = request<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newBuilder</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cacheControl</span>(CacheControl<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.FORCE</span>_CACHE)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.build</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
Response response2 = client<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newCall</span>(request)<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.execute</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
if (!response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.isSuccessful</span>()) throw new IOException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Unexpected code "</span> + response2)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

String response2Body = response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.body</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.string</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 response:          "</span> + response2)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 cache response:    "</span> + response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cacheResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 network response:  "</span> + response2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.networkResponse</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.println</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Response 2 equals Response 1? "</span> + response1Body<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.equals</span>(response2Body))<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li></ul>

取消操作

网络操作中，经常会使用到对请求的cancel操作，okhttp的也提供了这方面的接口，call的cancel操作。使用Call.cancel()可以立即停止掉一个正在执行的call。如果一个线程正在写请求或者读响应，将会引发IOException，同时可以通过Request.Builder.tag(Object tag)给请求设置一个标签，并使用OkHttpClient.cancel(Object tag)来取消所有带有这个tag的call。但如果该请求已经在做读写操作的时候，cancel是无法成功的，会抛出IOException异常。

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">public void canceltest() throws Exception {
Request request = new Request<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Builder</span>()
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.url</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://httpbin.org/delay/2"</span>) // This URL is served with a <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span> second delay.
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.build</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

final long startNanos = System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.nanoTime</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
final <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">Call</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">call</span> = client<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.newCall</span>(request)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

// Schedule a job to cancel the <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">call</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">in</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span> second.
executor<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.schedule</span>(new Runnable() {
@Override
public void run() {
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.printf</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%.2f Canceling call.%n"</span>, (System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.nanoTime</span>() - startNanos) / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1e9</span>f)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">call</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cancel</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.printf</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%.2f Canceled call.%n"</span>, (System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.nanoTime</span>() - startNanos) / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1e9</span>f)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
}
}, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>, TimeUnit<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.SECONDS</span>)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

try {
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.printf</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%.2f Executing call.%n"</span>, (System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.nanoTime</span>() - startNanos) / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1e9</span>f)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
Response response = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">call</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.execute</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.printf</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"call is cancel:"</span> + <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">call</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.isCanceled</span>() + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%n"</span>)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.printf</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%.2f Call was expected to fail, but completed: %s%n"</span>,
(System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.nanoTime</span>() - startNanos) / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1e9</span>f, response)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
} catch (IOException e) {
System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.out</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.printf</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%.2f Call failed as expected: %s%n"</span>,
(System<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.nanoTime</span>() - startNanos) / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1e9</span>f, e)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
}
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li></ul>

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简单的对于OKHttp的使用就介绍到这里，下次将重点从源码角度介绍整个OKHttp是如何运转的。