Java套接字

前言：　

　　本文补充一下Java关于套接字方面的内容，因为其应用相对比较简单，所以下面介绍两个程序实例。

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1.Socket对接过程

(注：这是之前在网上见过一张图片，大致过程还是比较清晰的）

分析：

• Socket对接之后的数据传送类似于文件的读写；
• 流套接字采用TCP传输数据流，一旦数据发送失败将重传，所以具有安全无损的特点。

2.实例一【Server->Client(1:1)】

 1 package socket;
 2
 3 import java.io.DataInputStream;
 4 import java.io.DataOutputStream;
 5 import java.io.IOException;
 6 import java.net.Inet4Address;
 7 import java.net.InetAddress;
 8 import java.net.ServerSocket;
 9 import java.net.Socket;
10 import java.util.Date;
11
12 public class Server {
13
14     public Server(){
15         try {
16             //服务端开启端口8000
17             ServerSocket serverSocket = new ServerSocket(8000);
18             System.out.println("server start at:"+new Date());
19             //等待客户端相应
20             Socket socket  = serverSocket.accept();
21             InetAddress address = socket.getInetAddress();
22             System.out.println("connected with address:"+address.getHostAddress());
23             DataInputStream input = new DataInputStream(socket.getInputStream());
24             DataOutputStream output = new DataOutputStream(socket.getOutputStream());
25
26             //while(true){
27             int num = input.readInt();
28             System.out.println(num);
29             //}
30
31         } catch (IOException e) {
32             e.printStackTrace();
33         }
34     }
35
36     public static void main(String[] args) {
37         new Server();
38     }
39
40 }

 1 package socket;
 2
 3 import java.io.DataInputStream;
 4 import java.io.DataOutputStream;
 5 import java.net.Socket;
 6
 7 public class Client {
 8     public static void main(String[] args) throws Exception {
 9
10         System.out.println("--client--");
11
12         //Socket(,)内参数分别设为服务端IP和端口
13         Socket socket = new Socket("localhost", 8000);
14
15         DataInputStream input = new DataInputStream(socket.getInputStream());
16         DataOutputStream output = new DataOutputStream(socket.getOutputStream());
17
18         int x = 222;
19         output.writeInt(x);
20         System.out.println("data convented:"+x);
21     }
22 }

服务端输出（执行之后显示红点，表示等待中...）：

server start at:Sat Aug 15 19:39:40 CST 2015
connected with address:127.0.0.1
222

客户端输出：

--client--
data convented:222

3.实例二【Server->Client(1:n)】

 1 package socket;
 2
 3 import java.io.DataInputStream;
 4 import java.io.DataOutputStream;
 5 import java.net.InetAddress;
 6 import java.net.ServerSocket;
 7 import java.net.Socket;
 8 import java.util.Date;
 9
10 public class SuperServer {
11     private int countOfClient=0;
12     public SuperServer() {
13         try {
14             ServerSocket serverSocket = new ServerSocket(8000);
15             System.out.println("server start at:" + new Date());
16
17             while (true) {
18                 Socket socket = serverSocket.accept();
19                 InetAddress address = socket.getInetAddress();
20                 System.out.println("connected with address:"
21                         + address.getHostAddress());
22                 //为每一位Client创建一个单独的线程
23                 new Thread(new ConnectTask(socket)).start();
24                 countOfClient++;
25                 System.out.println("this is the "+countOfClient + "(th) of client. ");
26             }
27         } catch (Exception e) {
28             e.printStackTrace();
29         }
30
31     }
32
33     public static void main(String[] args) {
34         new SuperServer();
35     }
36
37     class ConnectTask implements Runnable {
38         private Socket socket = null;
39
40         public ConnectTask(Socket socket) {
41             this.socket = socket;
42         }
43
44         @Override
45         public void run() {
46             try {
47                 DataInputStream input = new DataInputStream(
48                         socket.getInputStream());
49                 DataOutputStream output = new DataOutputStream(
50                         socket.getOutputStream());
51
52                 int numFromClient = input.readInt();
53                 System.out.println("number from client:"+numFromClient);
54             } catch (Exception e) {
55                 e.printStackTrace();
56             }
57         }
58
59     }
60
61 }

　　以上代码中，服务端创建多线程，给每一个对接的客户端分一个独立的线程；客户端代码不变，还是实例一的代码。程序输出跟实例一近似，只不过这是服务端一直运行着，可供多个客户端连接。（因为独立分配线程，程序运行时资源比较浪费，所以代码仅供参考，有待优化！）