一個Android Socket開發的實例

       Android客戶端通過socket與服務器進行通信可以分為以下幾步：

       應用程序與服務器通信可以采用兩種模式：TCP可靠通信和UDP不可靠通信。

       （1）通過IP地址和端口實例化Socket，請求連接服務器：

1. socket = new Socket(HOST, PORT);   //host:為服務器的IP地址  port：為服務器的端口號  

       （2）獲取Socket流以進行讀寫，並把流包裝進BufferWriter或者PrintWriter：

1. PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true);    

        這裡涉及了三個類：socket.getOutputStream得到socket的輸出字節流，OutputStreamWriter是字節流向字符流轉換的橋梁，BufferWriter是字符流，然後再包裝進PrintWriter。

       （3）對Socket進行讀寫

1. if (socket.isConnected()) {  
2.     if (!socket.isOutputShutdown()) {  
3.         out.println(msg);  
4.     }  
5. }  

       （4）關閉打開的流

1. out.close();  

        在寫代碼的過程中一定要注意對socket  輸入流 、輸出流的關閉。

        下面是一個簡單的例子：

        main.xml：

1. <?xml version="1.0" encoding="utf-8"?>  
2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    
3.     android:orientation="vertical"   
4.     android:layout_width="fill_parent"    
5.     android:layout_height="fill_parent">    
6.     <TextView   
7.         android:id="@+id/TextView"   
8.         android:singleLine="false"    
9.         android:layout_width="fill_parent"    
10.         android:layout_height="wrap_content" />    
11.     <EditText android:hint="content"   
12.         android:id="@+id/EditText01"    
13.         android:layout_width="fill_parent"    
14.         android:layout_height="wrap_content">    
15.     </EditText>    
16.     <Button   
17.         android:text="send"   
18.         android:id="@+id/Button02"    
19.         android:layout_width="fill_parent"    
20.         android:layout_height="wrap_content">    
21.     </Button>    
22. </LinearLayout>   

       下面是android客戶端的源代碼：

1. package com.android.SocketDemo;  
2.   
3. import java.io.BufferedReader;  
4. import java.io.BufferedWriter;  
5. import java.io.IOException;  
6. import java.io.InputStreamReader;  
7. import java.io.OutputStreamWriter;  
8. import java.io.PrintWriter;  
9. import java.net.Socket;  
10.   
11. import android.app.Activity;  
12. import android.app.AlertDialog;  
13. import android.content.DialogInterface;  
14. import android.os.Bundle;  
15. import android.os.Handler;  
16. import android.os.Message;  
17. import android.view.View;  
18. import android.widget.Button;  
19. import android.widget.EditText;  
20. import android.widget.TextView;  
21.   
22. public class SocketDemo extends Activity implements Runnable {  
23.     private TextView tv_msg = null;  
24.     private EditText ed_msg = null;  
25.     private Button btn_send = null;  
26. //    private Button btn_login = null;  
27.     private static final String HOST = "192.168.1.223";  
28.     private static final int PORT = 9999;  
29.     private Socket socket = null;  
30.     private BufferedReader in = null;  
31.     private PrintWriter out = null;  
32.     private String content = "";  
33.   
34.     /** Called when the activity is first created. */  
35.     @Override  
36.     public void onCreate(Bundle savedInstanceState) {  
37.         super.onCreate(savedInstanceState);  
38.         setContentView(R.layout.main);  
39.   
40.         tv_msg = (TextView) findViewById(R.id.TextView);  
41.         ed_msg = (EditText) findViewById(R.id.EditText01);  
42. //        btn_login = (Button) findViewById(R.id.Button01);  
43.         btn_send = (Button) findViewById(R.id.Button02);  
44.   
45.         try {  
46.             socket = new Socket(HOST, PORT);  
47.             in = new BufferedReader(new InputStreamReader(socket.getInputStream()));  
48.             out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(  
49.                     socket.getOutputStream())), true);  
50.         } catch (IOException ex) {  
51.             ex.printStackTrace();  
52.             ShowDialog("login exception" + ex.getMessage());  
53.         }  
54.         btn_send.setOnClickListener(new Button.OnClickListener() {  
55.   
56.             @Override  
57.             public void onClick(View v) {  
58.                 // TODO Auto-generated method stub  
59.                 String msg = ed_msg.getText().toString();  
60.                 if (socket.isConnected()) {  
61.                     if (!socket.isOutputShutdown()) {  
62.                         out.println(msg);  
63.                     }  
64.                 }  
65.             }  
66.         });  
67.         new Thread(SocketDemo.this).start();  
68.     }  
69.   
70.     public void ShowDialog(String msg) {  
71.         new AlertDialog.Builder(this).setTitle("notification").setMessage(msg)  
72.                 .setPositiveButton("ok", new DialogInterface.OnClickListener() {  
73.   
74.                     @Override  
75.                     public void onClick(DialogInterface dialog, int which) {  
76.                         // TODO Auto-generated method stub  
77.   
78.                     }  
79.                 }).show();  
80.     }  
81.   
82.     public void run() {  
83.         try {  
84.             while (true) {  
85.                 if (socket.isConnected()) {  
86.                     if (!socket.isInputShutdown()) {  
87.                         if ((content = in.readLine()) != null) {  
88.                             content += "\n";  
89.                             mHandler.sendMessage(mHandler.obtainMessage());  
90.                         } else {  
91.   
92.                         }  
93.                     }  
94.                 }  
95.             }  
96.         } catch (Exception e) {  
97.             e.printStackTrace();  
98.         }  
99.     }  
100.   
101.     public Handler mHandler = new Handler() {  
102.         public void handleMessage(Message msg) {  
103.             super.handleMessage(msg);  
104.             tv_msg.setText(tv_msg.getText().toString() + content);  
105.         }  
106.     };  
107. }  

       下面是服務器端得java代碼：

1. import java.io.BufferedReader;  
2. import java.io.BufferedWriter;  
3. import java.io.IOException;  
4. import java.io.InputStreamReader;  
5. import java.io.OutputStreamWriter;  
6. import java.io.PrintWriter;  
7. import java.net.ServerSocket;  
8. import java.net.Socket;  
9. import java.util.ArrayList;  
10. import java.util.List;  
11. import java.util.concurrent.ExecutorService;  
12. import java.util.concurrent.Executors;  
13.   
14.   
15. public class Main {  
16.     private static final int PORT = 9999;  
17.     private List<Socket> mList = new ArrayList<Socket>();  
18.     private ServerSocket server = null;  
19.     private ExecutorService mExecutorService = null; //thread pool  
20.       
21.     public static void main(String[] args) {  
22.         new Main();  
23.     }  
24.     public Main() {  
25.         try {  
26.             server = new ServerSocket(PORT);  
27.             mExecutorService = Executors.newCachedThreadPool();  //create a thread pool  
28.             System.out.print("server start ...");  
29.             Socket client = null;  
30.             while(true) {  
31.                 client = server.accept();  
32.                 mList.add(client);  
33.                 mExecutorService.execute(new Service(client)); //start a new thread to handle the connection  
34.             }  
35.         }catch (Exception e) {  
36.             e.printStackTrace();  
37.         }  
38.     }  
39.     class Service implements Runnable {  
40.             private Socket socket;  
41.             private BufferedReader in = null;  
42.             private String msg = "";  
43.               
44.             public Service(Socket socket) {  
45.                 this.socket = socket;  
46.                 try {  
47.                     in = new BufferedReader(new InputStreamReader(socket.getInputStream()));  
48.                     msg = "user" +this.socket.getInetAddress() + "come toal:"  
49.                         +mList.size();  
50.                     this.sendmsg();  
51.                 } catch (IOException e) {  
52.                     e.printStackTrace();  
53.                 }  
54.                   
55.             }  
56.   
57.             @Override  
58.             public void run() {  
59.                 // TODO Auto-generated method stub  
60.                 try {  
61.                     while(true) {  
62.                         if((msg = in.readLine())!= null) {  
63.                             if(msg.equals("exit")) {  
64.                                 System.out.println("ssssssss");  
65.                                 mList.remove(socket);  
66.                                 in.close();  
67.                                 msg = "user:" + socket.getInetAddress()  
68.                                     + "exit total:" + mList.size();  
69.                                 socket.close();  
70.                                 this.sendmsg();  
71.                                 break;  
72.                             } else {  
73.                                 msg = socket.getInetAddress() + ":" + msg;  
74.                                 this.sendmsg();  
75.                             }  
76.                         }  
77.                     }  
78.                 } catch (Exception e) {  
79.                     e.printStackTrace();  
80.                 }  
81.             }  
82.             
83.            public void sendmsg() {  
84.                System.out.println(msg);  
85.                int num =mList.size();  
86.                for (int index = 0; index < num; index ++) {  
87.                    Socket mSocket = mList.get(index);  
88.                    PrintWriter pout = null;  
89.                    try {  
90.                        pout = new PrintWriter(new BufferedWriter(  
91.                                new OutputStreamWriter(mSocket.getOutputStream())),true);  
92.                        pout.println(msg);  
93.                    }catch (IOException e) {  
94.                        e.printStackTrace();  
95.                    }  
96.                }  
97.            }  
98.         }      
99. }  

       注意在AndroidManifest.xml中加入對網絡的訪問權限：

1. <uses-permission android:name="android.permission.INTERNET"></uses-permission>