Android网络编程Socket长连接

浏览数：130 / 时间：2015年06月11日

在实际的应用中客户端可能需要和服务器端保持长时间的通信，即服务器需要不断地读取客户端数据，并向客户端写入数据；客户端也需要不断地读取服务器数据，并向服务器写入数据。

简单实现代码如下：

 1 public class MyServer {
 2    //定义保存所有Socket的ArrayList
 3    public staticArrayList socketList = newArrayList();
 4   
 5    public static voidmain(String[] args) throws IOException {
 6       // TODOAuto-generated method stub
 7       ServerSocket ss = newServerSocket(30000);
 8       while(true){
 9          //此代码会阻塞，将一直等待别人连接
10          Socket s = ss.accept();
11          socketList.add(s);
12          //每当客户端连接后启动一条ServerThread线程为该客户端服务
13          new Thread(newServerThread(s)).start();
14       }
15    }
16 }
17 服务端通信线程
18 public classServerThread implements Runnable {
19    //定义当前线程所处理的Socket
20    Socket s = null;
21    //该线程所处理的Socket所对应的输入流
22    BufferedReader br = null;
23    public ServerThread(Socket s) throws IOException {
24       this.s = s;
25       //初始化该Socket对应的输入流
26       br = newBufferedReader(new InputStreamReader(s.getInputStream(),
27             "utf-8"));
28    }
29    @Override
30    public void run() {
31       // TODOAuto-generated method stub
32       try
33       {
34          String content = null;
35          //采用循环不断从Socket中读取客户端发送过来的数据
36          while((content = readFromClient())!=null){
37             //遍历socketList中的每个Socket
38             //将读到的内容向每个Socket发送一次
39             for(Socket s : MyServer.socketList){
40                 OutputStream os = s.getOutputStream();
41                 os.write((content + "\n").getBytes("utf-8"));//注意发送消息的时候一定要加换行符，因为在readLine的时候看的就是换行符
42             }
43          }
44       }catch(IOException e) {
45          e.printStackTrace();
46       }
47    }
48   
49    public String readFromClient()
50    {
51       try{
52          return br.readLine();
53       }catch(IOException e){   //如果捕捉到异常，表明该Socket对应的客户端已经被关闭
54          //删除该Socket
55          MyServer.socketList.remove(s);
56       }
57       return null;
58    }
59 }

public classMainActivity extends Activity {
   EditText input, show;
   Button send;
   OutputStream os;
   Handler handler;
   @Override
   protected voidonCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      input = (EditText) findViewById(R.id.input);
      send = (Button) findViewById(R.id.send);
      show = (EditText) findViewById(R.id.show);
      handler = new Handler() {
         public voidhandleMessage(android.os.Message msg) {
            if (msg.what == 0x123) {
                show.append("\n" + msg.obj.toString());
            }
         };
      };
      newAsyncTask(){
         @Override
         protected String doInBackground(String... params) {
            // TODOAuto-generated method stub
            Socket s;
            try {
                s = new Socket("192.168.1.75", 30000);
                //客户端启动ClientThread线程，不断读取来自服务器的数据
                new Thread(newClientThread(s, handler)).start();
                os = s.getOutputStream();
            } catch(Exception e) {
                e.printStackTrace();
            }
            return null;
         }
      }.execute("");
      send.setOnClickListener(newOnClickListener() {
         @Override
         public voidonClick(View v) {
            // TODOAuto-generated method stub
            try {
                //将用户在文本框中输入的内容写入网络
                os.write((input.getText().toString() + "\r\n")
                      .getBytes("utf-8"));
                input.setText("");
            } catch(IOException e) {
                // TODOAuto-generated catch block
                e.printStackTrace();
            }
         }
      });
   }
}
客户端通信线程
public classClientThread implements Runnable {
   private Socket s;  //该线程负责处理的Socket
   private Handler handler;
   //该线程所处理的Socket对应的输入流
   BufferedReader br = null;
   public ClientThread(Socket s, Handler handler) throws IOException {
      this.s = s;
      this.handler = handler;
      br = newBufferedReader(new InputStreamReader(s.getInputStream()));
   }
   @Override
   public void run() {
      // TODOAuto-generated method stub
      try {
         String content = null;
         //不断读取Socket输入流中的内容
         while ((content = br.readLine()) != null) {
            //每当读到来自服务器的数据后，发送消息通知程序界面显示数据
            Message msg = newMessage();
            msg.what = 0x123;
            msg.obj = content;
            handler.sendMessage(msg);
         }
      } catch(Exception e) {
         e.printStackTrace();
      }
   }
}