Android网络请求框架—OKHttp 源码解析

总体流程

整个流程是，通过

OkHttpClient

将构建的

Request

转换为Call，然后在RealCall中进行异步或同步任务，最后通过一些的拦截器

interceptor

发出网络请求和得到返回的

response

。

将流程大概是这么个流程，大家可以有个大概的印象，继续向下看：



OkHttp流程图.jpg

为了让大家有更深的印象，我准备追踪一个

GET

网络请求的具体流程，来介绍在源码中发生了什么。

GET请求过程

这是利用

OkHttp

写一个Get请求步骤，这里是一个同步的请求,异步的下面也会说：

//HTTP GET
public String get(String url) throws IOException {
//新建OKHttpClient客户端
OkHttpClient client = new OkHttpClient();
//新建一个Request对象
Request request = new Request.Builder()
.url(url)
.build();
//Response为OKHttp中的响应
Response response = client.newCall(request).execute();
if (response.isSuccessful()) {
return response.body().string();
}else{
throw new IOException("Unexpected code " + response);
}
}

OKHttpClient：流程的总控制者

OkHttpClient的类设计图

使用OkHttp的时候我们都会创建一个OkHttpClient对象:

OkHttpClient client = new OkHttpClient();

这是做什么的呢？看下builder里面的参数：

final Dispatcher dispatcher;  //分发器
final Proxy proxy;  //代理
final List<Protocol> protocols; //协议
final List<ConnectionSpec> connectionSpecs; //传输层版本和连接协议
final List<Interceptor> interceptors; //拦截器
final List<Interceptor> networkInterceptors; //网络拦截器
final ProxySelector proxySelector; //代理选择
final CookieJar cookieJar; //cookie
final Cache cache; //缓存
final InternalCache internalCache;  //内部缓存
final SocketFactory socketFactory;  //socket 工厂
final SSLSocketFactory sslSocketFactory; //安全套接层socket 工厂，用于HTTPS
final CertificateChainCleaner certificateChainCleaner; // 验证确认响应证书 适用 HTTPS 请求连接的主机名。
final HostnameVerifier hostnameVerifier;    //  主机名字确认
final CertificatePinner certificatePinner;  //  证书链
final Authenticator proxyAuthentica
4000
tor;     //代理身份验证
final Authenticator authenticator;      // 本地身份验证
final ConnectionPool connectionPool;    //连接池,复用连接
final Dns dns;  //域名
final boolean followSslRedirects;  //安全套接层重定向
final boolean followRedirects;  //本地重定向
final boolean retryOnConnectionFailure; //重试连接失败
final int connectTimeout;    //连接超时
final int readTimeout; //read 超时
final int writeTimeout; //write 超时</Interceptor></Interceptor></ConnectionSpec></Protocol>

在这些声明的对象中可以看出来，几乎所有用到的类都和

OkHttpClient

有关系。事实上，你能够通过它来设置改变一些参数，因为他是通过

建造者模式

实现的，因此你可以通过

builder()

来设置。如果不进行设置，在

Builder

中就会使用默认的设置：

dispatcher = new Dispatcher();
protocols = DEFAULT_PROTOCOLS;
connectionSpecs = DEFAULT_CONNECTION_SPECS;
proxySelector = ProxySelector.getDefault();
cookieJar = CookieJar.NO_COOKIES;
socketFactory = SocketFactory.getDefault();
hostnameVerifier = OkHostnameVerifier.INSTANCE;
certificatePinner = CertificatePinner.DEFAULT;
proxyAuthenticator = Authenticator.NONE;
authenticator = Authenticator.NONE;
connectionPool = new ConnectionPool();
dns = Dns.SYSTEM;
followSslRedirects = true;
followRedirects = true;
retryOnConnectionFailure = true;
connectTimeout = 10_000;
readTimeout = 10_000;
writeTimeout = 10_000;

看到这，如果你还不明白的话，也没关系，在

OkHttp

中只是设置用的的各个东西。真正的流程要从里面的

newCall()

方法中说起：

/**
*  Prepares the {@code request} to be executed at some point in the future.
*  准备将要被执行的request
*/
@Override
public Call newCall(Request request) {
return new RealCall(this, request);
}

当通过

建造者模式

创建了

Request

之后（这个没什么好说），紧接着就通过下面的代码来获得

Response

大家还记得上面做

GET

请求时的这句代码吧：

Response response = client.newCall(request).execute();

这就代码就开启了整个GET请求的流程：

RealCall：真正的请求执行者。

先看一下他的构造方法：

protected RealCall(OkHttpClient client, Request originalRequest) {
this.client = client;
this.originalRequest = originalRequest;
this.retryAndFollowUpInterceptor = new RetryAndFollowUpInterceptor(client);
}

可以看到他传过来一个

OkHttpClient

对象和一个

originalRequest

（我们创建的

Request

）。

接下来看它的

execute()

方法：

@Override
public Response execute() throws IOException {
synchronized (this) {
if (executed) throw new IllegalStateException("Already Executed"); //(1)
executed = true;
}
try {
client.dispatcher.executed(this);//(2)
Response result = getResponseWithInterceptorChain();//(3)
if (result == null) throw new IOException("Canceled");
return result;
}finally {
client.dispatcher.finished(this);//(4)
}
}

检查这个 

call

是否已经被执行了，每个 

call

 只能被执行一次，如果想要一个完全一样的 

call

，可以利用 

all#clone

 方法进行克隆。
利用 

client.dispatcher().executed(this)

 来进行实际执行，

dispatcher

 是刚才看到的 

OkHttpClient.Builder

 的成员之一，它的文档说自己是异步 

HTTP

请求的执行策略，现在看来，同步请求它也有掺和。
调用 

getResponseWithInterceptorChain()

 函数获取 

HTTP

 返回结果，从函数名可以看出，这一步还会进行一系列“拦截”操作。

最后还要通知 

dispatcher

 自己已经执行完毕。

dispatcher

 这里我们不过度关注，在同步执行的流程中，涉及到

dispatcher

 的内容只不过是告知它我们的执行状态，比如开始执行了（调用 

executed

），比如执行完毕了（调用 

finished

），在异步执行流程中它会有更多的参与。

真正发出网络请求，解析返回结果的，还是

getResponseWithInterceptorChain

：

//拦截器的责任链。
private Response getResponseWithInterceptorChain() throws IOException {
// Build a full stack of interceptors.
List<Interceptor> interceptors = new ArrayList<>();
interceptors.addAll(client.interceptors());     //(1)
interceptors.add(retryAndFollowUpInterceptor);    //(2)
interceptors.add(new BridgeInterceptor(client.cookieJar()));    //(3)
interceptors.add(new CacheInterceptor(client.internalCache()));    //(4)
interceptors.add(new ConnectInterceptor(client));    //(5)
if (!retryAndFollowUpInterceptor.isForWebSocket()) {
interceptors.addAll(client.networkInterceptors());    //(6)
}
interceptors.add(new CallServerInterceptor(
retryAndFollowUpInterceptor.isForWebSocket()));     //(7)

Interceptor.Chain chain = new RealInterceptorChain(
interceptors, null, null, null, 0, originalRequest);
return chain.proceed(originalRequest); //  <<=========开始链式调用 }<="" code=""/></Interceptor>

在配置 

OkHttpClient

 时设置的 

interceptors

；
负责失败重试以及重定向的 

RetryAndFollowUpInterceptor

；
负责把用户构造的请求转换为发送到服务器的请求、把服务器返回的响应转换为用户友好的响应的 

BridgeInterceptor

；
负责读取缓存直接返回、更新缓存的 

CacheInterceptor

；
负责和服务器建立连接的 

ConnectInterceptor

；
配置 

OkHttpClient

 时设置的 

networkInterceptors

；
负责向服务器发送请求数据、从服务器读取响应数据的

CallServerInterceptor

。
在

return
chain.proceed(originalRequest);

中开启链式调用：

RealInterceptorChain

public Response proceed(Request request, StreamAllocation streamAllocation, HttpCodec httpCodec,
Connection connection) throws IOException {
if (index >= interceptors.size()) throw new AssertionError();

calls++;

// If we already have a stream, confirm that the incoming request will use it.
//如果我们已经有一个stream。确定即将到来的request会使用它
if (this.httpCodec != null && !sameConnection(request.url())) {
throw new IllegalStateException("network interceptor " + interceptors.get(index - 1)
+ " must retain the same host and port");
}

// If we already have a stream, confirm that this is the only call to chain.proceed().
//如果我们已经有一个stream， 确定chain.proceed()唯一的call
if (this.httpCodec != null && calls > 1) {
throw new IllegalStateException("network interceptor " + interceptors.get(index - 1)
+ " must call proceed() exactly once");
}

// Call the next interceptor in the chain.
//调用链的下一个拦截器
RealInterceptorChain next = new RealInterceptorChain(
interceptors, streamAllocation, httpCodec, connection, index + 1, request);
Interceptor interceptor = interceptors.get(index);
Response response = interceptor.intercept(next);

// Confirm that the next interceptor made its required call to chain.proceed().
if (httpCodec != null && index + 1 < interceptors.size() && next.calls != 1) {
throw new IllegalStateException("network interceptor " + interceptor
+ " must call proceed() exactly once");
}

// Confirm that the intercepted response isn't null.
if (response == null) {
throw new NullPointerException("interceptor " + interceptor + " returned null");
}

return response;
}
`

代码很多，但是主要是进行一些判断，主要的代码在这：

// Call the next interceptor in the chain.
//调用链的下一个拦截器
RealInterceptorChain next = new RealInterceptorChain(
interceptors, streamAllocation, httpCodec, connection, index + 1, request);    //(1)
Interceptor interceptor = interceptors.get(index);     //(2)
Response response = interceptor.intercept(next);    //(3)

实例化下一个拦截器对应的

RealIterceptorChain

对象，这个对象会在传递给当前的拦截器
得到当前的拦截器：

interceptors

是存放拦截器的

ArryList

调用当前拦截器的

intercept()

方法，并将下一个拦截器的

RealIterceptorChain

对象传递下去
除了在client中自己设置的

interceptor

,第一个调用的就是

retryAndFollowUpInterceptor

RetryAndFollowUpInterceptor:负责失败重试以及重定向

直接上代码

@Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request();
streamAllocation = new StreamAllocation(
client.connectionPool(), createAddress(request.url()));
int followUpCount = 0;
Response priorResponse = null;
while (true) {
if (canceled) {
streamAllocation.release();
throw new IOException("Canceled");
}

Response response = null;
boolean releaseConnection = true;
try {
response = ((RealInterceptorChain) chain).proceed(request, streamAllocation, null, null);    //(1)
releaseConnection = false;
} catch (RouteException e) {
// The attempt to connect via a route failed. The request will not have been sent.
//通过路线连接失败，请求将不会再发送
if (!recover(e.getLastConnectException(), true, request)) throw e.getLastConnectException();
releaseConnection = false;
continue;
} catch (IOException e) {
// An attempt to communicate with a server failed. The request may have been sent.
// 与服务器尝试通信失败，请求不会再发送。
if (!recover(e, false, request)) throw e;
releaseConnection = false;
continue;
} finally {
// We're throwing an unchecked exception. Release any resources.
//抛出未检查的异常，释放资源
if (releaseConnection) {
streamAllocation.streamFailed(null);
streamAllocation.release();
}
}

// Attach the prior response if it exists. Such responses never have a body.
// 附加上先前存在的response。这样的response从来没有body
// TODO: 2016/8/23 这里没赋值，岂不是一直为空？
if (priorResponse != null) { //  (2)
response = response.newBuilder()
.priorResponse(priorResponse.newBuilder()
.body(null)
.build())
.build();
}

Request followUp = followUpRequest(response); //判断状态码 (3)
if (followUp == null){
if (!forWebSocket) {
streamAllocation.release();
}
return response;
}

closeQuietly(response.body());

if (++followUpCount > MAX_FOLLOW_UPS) {
streamAllocation.release();
throw new ProtocolException("Too many follow-up requests: " + followUpCount);
}

if (followUp.body() instanceof UnrepeatableRequestBody) {
throw new HttpRetryException("Cannot retry streamed HTTP body", response.code());
}

if (!sameConnection(response, followUp.url())) {
streamAllocation.release();
streamAllocation = new StreamAllocation(
client.connectionPool(), createAddress(followUp.url()));
} else if (streamAllocation.codec() != null) {
throw new IllegalStateException("Closing the body of " + response
+ " didn't close its backing stream. Bad interceptor?");
}

request = followUp;
priorResponse = response;
}
}

这里是最关键的代码，可以看出在

response
= ((RealInterceptorChain) chain).proceed(request, streamAllocation, null, null);

中直接调用了下一个拦截器，然后捕获可能的异常来进行操作
这里没看太懂，有点坑，以后补
这里对于返回的response的状态码进行判断，然后进行处理

BridgeInterceptor：

负责把用户构造的请求转换为发送到服务器的请求、把服务器返回的响应转换为用户友好的响应的 。

@Override
public Response intercept(Chain chain) throws IOException {
Request userRequest = chain.request();
Request.Builder requestBuilder = userRequest.newBuilder();

//检查request。将用户的request转换为发送到server的请求
RequestBody body = userRequest.body();     //(1)
if (body != null) {
MediaType contentType = body.contentType();
if (contentType != null) {
requestBuilder.header("Content-Type", contentType.toString());
}

long contentLength = body.contentLength();
if (contentLength != -1) {
requestBuilder.header("Content-Length", Long.toString(contentLength));
requestBuilder.removeHeader("Transfer-Encoding");
} else {
requestBuilder.header("Transfer-Encoding", "chunked");
requestBuilder.removeHeader("Content-Length");
}
}

if (userRequest.header("Host") == null) {
requestBuilder.header("Host", hostHeader(userRequest.url(), false));
}

if (userRequest.header("Connection") == null) {
requestBuilder.header("Connection", "Keep-Alive");
}
// If we add an "Accept-Encoding: gzip" header field we're responsible for also decompressing
// the transfer stream.
//GZIP压缩
boolean transparentGzip = false;
if (userRequest.header("Accept-Encoding") == null) {
transparentGzip = true;
requestBuilder.header("Accept-Encoding", "gzip");
}

List<Cookie> cookies = cookieJar.loadForRequest(userRequest.url());
if (!cookies.isEmpty()) {
requestBuilder.header("Cookie", cookieHeader(cookies));
}

if (userRequest.header("User-Agent") == null) {
requestBuilder.header("User-Agent", Version.userAgent());
}

Response networkResponse = chain.proceed(requestBuilder.build());   //(2)

HttpHeaders.receiveHeaders(cookieJar, userRequest.url(), networkResponse.headers()); //(3)

Response.Builder responseBuilder = networkResponse.newBuilder()
.request(userRequest);

if (transparentGzip
&& "gzip".equalsIgnoreCase(networkResponse.header("Content-Encoding"))
&& HttpHeaders.hasBody(networkResponse)) {
GzipSource responseBody = new GzipSource(networkResponse.body().source());
Headers strippedHeaders = networkResponse.headers().newBuilder()
.removeAll("Content-Encoding")
.removeAll("Content-Length")
.build();
responseBuilder.headers(strippedHeaders);
responseBuilder.body(new RealResponseBody(strippedHeaders, Okio.buffer(responseBody)));
}

return responseBuilder.build();
}</Cookie>

在（1）和（2）之间，

BridgeInterceptor

对于

request

的格式进行检查，让构建了一个新的

request

调用下一个

interceptor

来得到response
（3）下面就是对得到的response进行一些判断操作，最后将结果返回。

@Override
public Response intercept(Chain chain) throws IOException {
Response cacheCandidate = cache != null        //=============(1)
? cache.get(chain.request()) //通过request得到缓存
: null;

long now = System.currentTimeMillis();

CacheStrategy strategy = new CacheStrategy.Factory(now, chain.request(), cacheCandidate).get(); //根据request来得到缓存策略===========(2)
Request networkRequest = strategy.networkRequest;
Response cacheResponse = strategy.cacheResponse;

if (cache != null) {
cache.trackResponse(strategy);
}

if (cacheCandidate != null && cacheResponse == null) { //存在缓存的response，但是不允许缓存
closeQuietly(cacheCandidate.body()); // The cache candidate wasn't applicable. Close it. 缓存不适合，关闭
}

// If we're forbidden from using the network and the cache is insufficient, fail.
//如果我们禁止使用网络，且缓存为null，失败
if (networkRequest == null && cacheResponse == null) {
return new Response.Builder()
.request(chain.request())
.protocol(Protocol.HTTP_1_1)
.code(504)
.message("Unsatisfiable Request (only-if-cached)")
.body(EMPTY_BODY)
.sentRequestAtMillis(-1L)
.receivedResponseAtMillis(System.currentTimeMillis())
.build();
}

// If we don't need the network, we're done.
if (networkRequest == null) {  //没有网络请求，跳过网络，返回缓存
return cacheResponse.newBuilder()
.cacheResponse(stripBody(cacheResponse))
.build();
}

Response networkResponse = null;
try {
networkResponse = chain.proceed(networkRequest);//网络请求拦截器    //======(3)
} finally {
// If we're crashing on I/O or otherwise, don't leak the cache body.
//如果我们因为I/O或其他原因崩溃，不要泄漏缓存体
if (networkResponse == null && cacheCandidate != null) {
closeQuietly(cacheCandidate.body());
}
}

// If we have a cache response too, then we're doing a conditional get.========(4)
//如果我们有一个缓存的response，然后我们正在做一个条件GET
if (cacheResponse != null) {
if (validate(cacheResponse, networkResponse)) { //比较确定缓存response可用
Response response = cacheResponse.newBuilder()
.headers(combine(cacheResponse.headers(), networkResponse.headers()))
.cacheResponse(stripBody(cacheResponse))
.networkResponse(stripBody(networkResponse))
.build();
networkResponse.body().close();

// Update the cache after combining headers but before stripping the
// Content-Encoding header (as performed by initContentStream()).
//更新缓存，在剥离content-Encoding之前
cache.trackConditionalCacheHit();
cache.update(cacheResponse, response);
return response;
} else {
closeQuietly(cacheResponse.body());
}
}

Response response = networkResponse.newBuilder()
.cacheResponse(stripBody(cacheResponse))
.networkResponse(stripBody(networkResponse))
.build();

if (HttpHeaders.hasBody(response)) {    // =========(5)
CacheRequest cacheRequest = maybeCache(response, networkResponse.request(), cache);
response = cacheWritingResponse(cacheRequest, response);
}

return response;
}

首先，根据

request

来判断

cache

中是否有缓存的

response

，如果有，得到这个

response

，然后进行判断当前

response

是否有效，没有将

cacheCandate

赋值为空。
根据request判断缓存的策略，是否要使用了网络，缓存 或两者都使用
调用下一个拦截器，决定从网络上来得到

response

如果本地已经存在

cacheResponse

，那么让它和网络得到的

networkResponse

做比较，决定是否来更新缓存的

cacheResponse

缓存未经缓存过的

response

ConnectInterceptor:建立连接

@Override
public Response intercept(Chain chain) throws IOException {
RealInterceptorChain realChain = (RealInterceptorChain) chain;
Request request = realChain.request();
StreamAllocation streamAllocation = realChain.streamAllocation();

// We need the network to satisfy this request. Possibly for validating a conditional GET.
boolean doExtensiveHealthChecks = !request.method().equals("GET");
HttpCodec httpCodec = streamAllocation.newStream(client, doExtensiveHealthChecks);
RealConnection connection = streamAllocation.connection();

return realChain.proceed(request, streamAllocation, httpCodec, connection);
}

实际上建立连接就是创建了一个

HttpCodec

对象，它将在后面的步骤中被使用，那它又是何方神圣呢？它是对 

HTTP

 协议操作的抽象，有两个实现：

Http1Codec

和

Http2Codec

，顾名思义，它们分别对应 

HTTP/1.1

 和

HTTP/2

 版本的实现。
在Http1Codec中，它利用 Okio 对Socket的读写操作进行封装，

Okio

 以后有机会再进行分析，现在让我们对它们保持一个简单地认识：它对java.io和java.nio进行了封装，让我们更便捷高效的进行
IO 操作。
而创建

HttpCodec

对象的过程涉及到

StreamAllocation、RealConnection

，代码较长，这里就不展开，这个过程概括来说，就是找到一个可用的

RealConnection

，再利用

RealConnection

的输入输出（

BufferedSource

和

BufferedSink

）创建

HttpCodec

对象，供后续步骤使用。

NetworkInterceptors

配置OkHttpClient时设置的 NetworkInterceptors。

CallServerInterceptor：发送和接收数据

@Override public Response intercept(Chain chain) throws IOException {
HttpCodec httpCodec = ((RealInterceptorChain) chain).httpStream();
StreamAllocation streamAllocation = ((RealInterceptorChain) chain).streamAllocation();
Request request = chain.request();

long sentRequestMillis = System.currentTimeMillis();
httpCodec.writeRequestHeaders(request);

if (HttpMethod.permitsRequestBody(request.method()) && request.body() != null) {   //===(1)
Sink requestBodyOut = httpCodec.createRequestBody(request, request.body().contentLength());
BufferedSink bufferedRequestBody = Okio.buffer(requestBodyOut);
request.body().writeTo(bufferedRequestBody);
bufferedRequestBody.close();
}

httpCodec.finishRequest();

Response response = httpCodec.readResponseHeaders()     //====(2)
.request(request)
.handshake(streamAllocation.connection().handshake())
.sentRequestAtMillis(sentRequestMillis)
.receivedResponseAtMillis(System.currentTimeMillis())
.build();

if (!forWebSocket || response.code() != 101) {
response = response.newBuilder()
.body(httpCodec.openResponseBody(response))
.build();
}

if ("close".equalsIgnoreCase(response.request().header("Connection"))
|| "close".equalsIgnoreCase(response.header("Connection"))) {
streamAllocation.noNewStreams();
}

int code = response.code();
if ((code == 204 || code == 205) && response.body().contentLength() > 0) {
throw new ProtocolException(
"HTTP " + code + " had non-zero Content-Length: " + response.body().contentLength());
}

return response;
}

检查请求方法，用

Httpcodec

处理

request

进行网络请求得到

response

返回r

esponse

总结

前面说了拦截器用了

责任链设计模式

,它将请求一层一层向下传，知道有一层能够得到Resposne就停止向下传递，然后将

response

向上面的拦截器传递，然后各个拦截器会对

respone

进行一些处理，最后会传到

RealCall

类中通过

execute

来得到

esponse

。

异步请求的流程：

异步get请求示例如下：

private final OkHttpClient client = new OkHttpClient();

public void run() throws Exception {
Request request = new Request.Builder()
.url("http://publicobject.com/helloworld.txt")
.build();

client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
e.printStackTrace();
}

@Override
public void onResponse(Call call, Response response) throws IOException {
if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

Headers responseHeaders = response.headers();
for (int i = 0, size = responseHeaders.size(); i < size; i++) {
System.out.println(responseHeaders.name(i) + ": " + responseHeaders.value(i));
}

System.out.println(response.body().string());
}
});
}

由代码中

client.newCall(request).enqueue(Callback)

，开始我们知道

client.newCall(request)

方法返回的是

RealCall

对象，接下来继续向下看

enqueue()

方法:

//异步任务使用
@Override
public void enqueue(Callback responseCallback) {
synchronized (this) {
if (executed) throw new IllegalStateException("Already Executed");
executed = true;
}
client.dispatcher().enqueue(new AsyncCall(responseCallback));
}

调用了上面我们没有详细说的

Dispatcher

类中的

enqueue(Call
)

方法.接着继续看：

synchronized void enqueue(AsyncCall call) {
if (runningAsyncCalls.size() < maxRequests && runningCallsForHost(call) < maxRequestsPerHost) {
runningAsyncCalls.add(call);
executorService().execute(call);
} else {
readyAsyncCalls.add(call);
}
}

如果中的

runningAsynCalls

不满，且

call

占用的

host

小于最大数量，则将

call

加入到

runningAsyncCalls

中执行，同时利用线程池执行

call

；否者将

call

加入到

readyAsyncCalls

中。

runningAsyncCalls

和

readyAsyncCalls

是什么呢？看下面：

/** Ready async calls in the order they'll be run. */
private final Deque<AsyncCall> readyAsyncCalls = new ArrayDeque<>(); //正在准备中的异步请求队列

/** Running asynchronous calls. Includes canceled calls that haven't finished yet. */
private final Deque<AsyncCall> runningAsyncCalls = new ArrayDeque<>(); //运行中的异步请求

/** Running synchronous calls. Includes canceled calls that haven't finished yet. */
private final Deque<RealCall> runningSyncCalls = new ArrayDeque<>(); //同步请求</RealCall></AsyncCall></AsyncCall>

call

加入到线程池中执行了。现在再看

AsynCall的

代码，它是

RealCall

中的内部类:

//异步请求
final class AsyncCall extends NamedRunnable {
private final Callback responseCallback;

private AsyncCall(Callback responseCallback) {
super("OkHttp %s", redactedUrl());
this.responseCallback = responseCallback;
}

String host() {
return originalRequest.url().host();
}

Request request() {
return originalRequest;
}

RealCall get() {
return RealCall.this;
}

@Override protected void execute() {
boolean signalledCallback = false;
try {
Response response = getResponseWithInterceptorChain();
if (retryAndFollowUpInterceptor.isCanceled()) {
signalledCallback = true;
responseCallback.onFailure(RealCall.this, new IOException("Canceled"));
} else {
signalledCallback = true;
responseCallback.onResponse(RealCall.this, response);
}
} catch (IOException e) {
if (signalledCallback) {
// Do not signal the callback twice!
Platform.get().log(INFO, "Callback failure for " + toLoggableString(), e);
} else {
responseCallback.onFailure(RealCall.this, e);
}
} finally {
client.dispatcher().finished(this);
}
}
}

AysncCall

中的

execute()

中的方法，同样是通过

Response
response = getResponseWithInterceptorChain();

来获得response，这样异步任务也同样通过了interceptor，剩下的流程就和上面一样了。

参考

OkHttp 官方教程解析
- 彻底入门 OkHttp 使用
拆轮子系列：拆 OkHttp