HTTPConnection与HTTPClient

HTTPConnection

用HttpConnection连接服务器有两种方法：GET和POSIT

GET

代码如下：

String urlstring = "http://localhost:8080/MyserverTest/Test?name=zhaoliu&password=12";
try {
URL url = new URL(urlstring);
URLConnection connect = url.openConnection();
HttpURLConnection httpconnection =(HttpURLConnection)connect;
//设置接收服务器的类型为GET
httpconnection.setConnectTimeout(30000);
httpconnection.setReadTimeout(30000);
httpconnection.setRequestMethod("GET");//用GET方法去接收服务器发来的数据。
//设置接收的数据类型
httpconnection.setRequestProperty("Accept-Charset", "utf-8");
// 设置可以接受序列化的java对象
httpconnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
//获得http状态码若为200说明接通正常
int code =httpconnection.getResponseCode();
if(code==HttpsURLConnection.HTTP_OK){
//建立接受数据流
BufferedReader br=new BufferedReader(new InputStreamReader(httpconnection.getInputStream()));

String line =br.readLine();
while(line!=null){
System.out.println(line);
line =br.readLine();
}
}

} catch(SocketTimeoutException e){
System.out.println("获取数据超时");

} catch(ConnectException e){
System.out.println("网络连接超时");

}catch(MalformedURLException e) {

e.printStackTrace();
} catch (IOException e) {

e.printStackTrace();
}
}

说明：

在Httpconnection中无论是GET方法还是POST方法都是先得到URL对象url，通过URLConnection connect = url.openConnection();将连接打开。用httpconnection.setRequestMethod(“GET”);确定接收数据的方法。用httpconnection.setRequestProperty(“Accept-Charset”, “utf-8”);设置接收的数据类型。用httpconnection.setRequestProperty(“Content-Type”, “application/x-www-form-urlencoded”);设置可以接受序列化的java对象。用int code =httpconnection.getResponseCode();获得http状态码若为200说明接通正常。用httpconnection.getInputStream()获得输入流。这样就可以对数据进行读取了。

由于post传输的地址不能将传输的内容放到网址的后面（是隐式的）所以必须有输出流。所以必须对输出流进行允许即：httpconnection.setDoOutput(true);。由于post不允许用缓冲，所以用：httpconnection.setUseCaches(false);。其他的与GET基本相同。

代码如下：

URL url = new URL(urlstring);
URLConnection connect = url.openConnection();
HttpURLConnection httpconnection =(HttpURLConnection)connect;
//设置接收服务器的类型为GET
httpconnection.setConnectTimeout(30000);
httpconnection.setReadTimeout(30000);
httpconnection.setRequestMethod("POST");
//设置接收的数据类型
httpconnection.setRequestProperty("Accept-Charset", "utf-8");
// 设置可以接受序列化的java对象
httpconnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
//获得http状态码若为200说明接通正常
httpconnection.setDoOutput(true);//设置向服务器发送数据是允许的，在post方法中这是必须为true
httpconnection.setDoInput(true);//设置可读取服务器的返回值，默认为true，可以不用设置
httpconnection.setUseCaches(false);//post方法不允许使用缓存
String s = "name=zhansan&password=123";
httpconnection.getOutputStream().write(s.getBytes());//设置输出流
int code =httpconnection.getResponseCode();//获得http状态码
if(code==HttpsURLConnection.HTTP_OK){//如果连接成功
//建立接受数据流
BufferedReader br=new BufferedReader(new InputStreamReader(httpconnection.getInputStream()));

String line =br.readLine();
while(line!=null){
System.out.println(line);
line =br.readLine();
}
}

} catch(SocketTimeoutException e){
System.out.println("获取数据超时");

} catch(ConnectException e){
System.out.println("网络连接超时");

}catch(MalformedURLException e) {

e.printStackTrace();
} catch (IOException e) {

e.printStackTrace();
}

HttpClient

ThhpClient也是分两种GET和POST

GET

代码如下：

String URLString = "http://localhost:8080/MyserverTest/Test?name=zhaoliu&password=12";
HttpClientBuilder builder = HttpClientBuilder.create();
builder.setConnectionTimeToLive(3000, TimeUnit.MICROSECONDS);//设置连接时间
HttpClient client = builder.build();//生成client
HttpGet get=new HttpGet(URLString);//设置为get方法
get.setHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
//设置服务器接收后数据的读取方式为utf8
try {
HttpResponse response=client.execute(get);//执行get方法得到服务器的返回的所有数据都在response中
StatusLine statusLine=response.getStatusLine();//httpClient访问服务器返回的表头，包含http状态码
int code=statusLine.getStatusCode();//得到状态码
if(code==HttpURLConnection.HTTP_OK){
HttpEntity entity=response.getEntity();//得到数据的实体
InputStream is=entity.getContent();//得到输入流
BufferedReader br=new BufferedReader(new InputStreamReader(is));
String line=br.readLine();
while(line!=null){
System.out.println(line);
line=br.readLine();
}
}
} catch (ClientProtocolException e1) {

e1.printStackTrace();
} catch (IOException e1) {

e1.printStackTrace();
}

GET与POST的的方法差不多和HttpConnection一样GET是显式，POST是隐式：（1）获得builder:HttpClientBuilder builder = HttpClientBuilder.create();（2）获得client ：HttpClient client = builder.build();//生成client。（3）获得GET方法或者POST方法。

GET代码如下：

String URLString = "http://localhost:8080/MyserverTest/Test?name=zhaoliu&password=12";
HttpClientBuilder builder = HttpClientBuilder.create();
builder.setConnectionTimeToLive(3000, TimeUnit.MICROSECONDS);//设置连接时间
HttpClient client = builder.build();//生成client
HttpGet get=new HttpGet(URLString);//设置为get方法
get.setHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
//设置服务器接收后数据的读取方式为utf8
try {
HttpResponse response=client.execute(get);//执行get方法得到服务器的返回的所有数据都在response中
StatusLine statusLine=response.getStatusLine();//httpClient访问服务器返回的表头，包含http状态码
int code=statusLine.getStatusCode();//得到状态码
if(code==HttpURLConnection.HTTP_OK){
HttpEntity entity=response.getEntity();//得到数据的实体
InputStream is=entity.getContent();//得到输入流
BufferedReader br=new BufferedReader(new InputStreamReader(is));
String line=br.readLine();
while(line!=null){
System.out.println(line);
line=br.readLine();
}
}
} catch (ClientProtocolException e1) {

e1.printStackTrace();
} catch (IOException e1) {

e1.printStackTrace();
}
}

POST代码如下：

String url = "http://localhost:8080/MyserverTest/Test";
HttpClientBuilder builder = HttpClientBuilder.create();
HttpClient client =builder.build();
HttpPost post1 =new HttpPost(url);
NameValuePair pair1 =new BasicNameValuePair("name", "zhaoliu");
NameValuePair pair2 =new BasicNameValuePair("password", "12");
ArrayList<NameValuePair> array = new ArrayList<>();
array.add(pair1);
array.add(pair2);
try {
post1.setEntity(new UrlEncodedFormEntity(array, "UTF-8"));
post1.setHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
HttpResponse request = client.execute(post1);
int code= request.getStatusLine().getStatusCode();
if(code==200){
HttpEntity entity=request.getEntity();
InputStream is =entity.getContent();
BufferedReader br =new BufferedReader(new InputStreamReader(is));
String line =br.readLine();
while(line!=null){
System.out.println(line);
line =br.readLine();
}

}
} catch (UnsupportedEncodingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}

这里有许多的地方不是很懂，以后用到再仔细看。

一篇不 错的文章：

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