Java版SockeDemo案例，有很详细的注释

 1 import java.io.BufferedReader;  2 import java.io.InputStreamReader;  3 import java.io.PrintWriter;  4 import java.net.Socket;  5 
 6 public class ServerThread extends Thread {  7     private static int number = 0; // 保存本进程的客户计数
 8 
 9     Socket socket = null; // 保存与本线程相关的Socket对象
10 
11     public ServerThread(Socket socket,int clientnum) { 12 
13         this.socket = socket; 14         number = clientnum; 15         System.out.println("当前在线的用户数: " + number); 16  } 17 
18  @Override 19     public void run() { 20         try { 21 
22             // 由Socket对象得到输入流,并构造相应的BufferedReader对象
23             BufferedReader in = new BufferedReader(new InputStreamReader(socket 24  .getInputStream())); 25 
26             // 由Socket对象得到输出流,并构造PrintWriter对象
27             PrintWriter out = new PrintWriter(socket.getOutputStream()); 28 
29             // 由系统标准输入设备构造BufferedReader对象
30             BufferedReader sysin = new BufferedReader(new InputStreamReader( 31  System.in)); 32 
33             // 在标准输出上打印从客户端读入的字符串
34             System.out.println("[Client " + number + "]: " + in.readLine()); 35 
36             String line; // 保存一行内容 37 
38             // 从标准输入读入一字符串
39             line = sysin.readLine(); 40 
41             while (!line.equals("bye")) { // 如果该字符串为 "bye",则停止循环 42 
43                 // 向客户端输出该字符串
44  out.println(line); 45 
46                 // 刷新输出流,使Client马上收到该字符串
47  out.flush(); 48 
49                 // 在系统标准输出上打印读入的字符串
50                 System.out.println("[Server]: " + line); 51 
52                 // 从Client读入一字符串,并打印到标准输出上
53                 System.out.println("[Client " + number + "]: " + in.readLine()); 54 
55                 // 从系统标准输入读入一字符串
56                 line = sysin.readLine(); 57  } 58 
59             out.close(); // 关闭Socket输出流
60             in.close(); // 关闭Socket输入流
61             socket.close(); // 关闭Socket
62         } catch (Exception e) { 63             System.out.println("Error. " + e); 64  } 65  } 66 }

import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; import java.net.Socket; /** * 客户端Socket * * @author Administrator * */
public class SocketClient { /** * 客户端Socket构造方法 */
    public SocketClient() { try { // 向本机的2121端口发出客户请求
            Socket socket = new Socket("localhost",2121); System.out.println("Established a connection..."); // 由系统标准输入设备构造BufferedReader对象
            BufferedReader sysin = new BufferedReader(new InputStreamReader( System.in)); // 由Socket对象得到输出流,并构造PrintWriter对象
            PrintWriter out = new PrintWriter(socket.getOutputStream()); // 由Socket对象得到输入流,并构造相应的BufferedReader对象
            BufferedReader in = new BufferedReader(new InputStreamReader(socket .getInputStream())); String line; // 保存一行内容 // 从系统标准输入读入一字符串
            line = sysin.readLine(); while (!line.equals("bye")) { // 若从标准输入读入的字符串为 "bye"则停止循环 // 将从系统标准输入读入的字符串输出到Server
 out.println(line); // 刷新输出流,使Server马上收到该字符串
 out.flush(); // 在系统标准输出上打印读入的字符串
                System.out.println("[Client]: " + line); // 从Server读入一字符串，并打印到标准输出上
                System.out.println("[Server]: " + in.readLine()); // 从系统标准输入读入一字符串
                line = sysin.readLine(); } out.close(); // 关闭Socket输出流
            in.close(); // 关闭Socket输入流
            socket.close(); // 关闭Socket
        } catch (Exception e) { System.out.println("Error. " + e); } } /** * 主方法 * * @param args */
    public static void main(String[] args) { new SocketClient(); } }

import java.net.ServerSocket; /** * 服务器端Socket * * @author Administrator * */
public class SocketServer { /** * 服务器端Socket构造方法 */

    public SocketServer() { try { int clientcount = 0; // 统计客户端总数

            boolean listening = true; // 是否对客户端进行监听
 ServerSocket server = null; // 服务器端Socket对象

            try { // 创建一个ServerSocket在端口2121监听客户请求
                server = new ServerSocket(2121); System.out.println("Server starts开始启动..."); } catch (Exception e) { System.out.println("Can not listen to. " + e); } while (listening) { // 客户端计数
                clientcount++; // 监听到客户请求,根据得到的Socket对象和客户计数创建服务线程,并启动之
                new ServerThread(server.accept(),clientcount).start(); } } catch (Exception e) { System.out.println("Error. " + e); } } /** * 主方法 * * @param args */
    public static void main(String[] args) { new SocketServer(); } }

package cn.kgc.sockettest.demo1; import java.io.*; import java.net.ServerSocket; import java.net.Socket; /** * 服务端 */
public class Server { public static void main(String[] args) { try { ServerSocket serverSocket = new ServerSocket(8080); System.out.println("服务器启动完成...监听中"); //开启监听，等待客户端的访问
            Socket socket = serverSocket.accept(); //获取输入流，因为是客户端向服务端发送了数据
            InputStream inputStream = socket.getInputStream(); //创建一个缓冲流
            BufferedReader br = new BufferedReader(new InputStreamReader(inputStream)); String info = null; while ((info = br.readLine()) != null) { System.out.println("这里是服务端 客户端是：" + info); } //向客户端做出相应
            OutputStream outputStream = socket.getOutputStream(); info = "这里是服务端我们接受到了你消息"; outputStream.write(info.getBytes()); outputStream.close(); } catch (IOException e) { e.printStackTrace(); } } }

package cn.kgc.sockettest.demo1; import java.io.*; import java.net.Socket; /** * 客户端 */
public class Client { public static void main(String[] args) { try { //IP地址
            Socket socket = new Socket("localhost",8080); OutputStream outputStream = socket.getOutputStream(); String info ="你好"; //输出！
 outputStream.write(info.getBytes()); socket.shutdownOutput(); //接受服务器的响应
            InputStream inputStream = socket.getInputStream(); BufferedReader br = new BufferedReader(new InputStreamReader(inputStream)); while((info =br.readLine())!=null){ System.out.println("接收到了服务器的响应:"+info); } outputStream.flush(); outputStream.close(); inputStream.close(); socket.close(); } catch (IOException e) { e.printStackTrace(); } } }

package cn.kgc.sockettest.demo1.demo2; import java.io.Serializable; public class User implements Serializable { private String userName; private String password; public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } @Override public String toString() { return "Server{" +
                "userName=‘" + userName + ‘‘‘ +
                ",password=‘" + password + ‘‘‘ +
                ‘}‘; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }

package cn.kgc.sockettest.demo1.demo2; import java.io.IOException; import java.io.InputStream; import java.io.ObjectInputStream; import java.net.ServerSocket; import java.net.Socket; public class Server { public static void main(String[] args) { try { ServerSocket serverSocket = new ServerSocket(8080); System.out.println("服务器启动完成。。。。。"); //开始监听
            Socket socket = serverSocket.accept(); InputStream inputStream = socket.getInputStream(); ObjectInputStream stream = new ObjectInputStream(inputStream); User user =(User)stream.readObject(); System.out.println("客户端发过来的数据是:"+user); } catch (Exception e) { e.printStackTrace(); } } }

package cn.kgc.sockettest.demo1.demo2; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.OutputStream; import java.net.Socket; /** * 客户端 */

public class Client { public static void main(String[] args) { try { Socket socket = new Socket("localhost",8080); OutputStream outputStream = socket.getOutputStream(); User user = new User(); user.setUserName("张三"); user.setPassword("admin"); //创建对象输出流
            ObjectOutputStream oos = new ObjectOutputStream(outputStream); //序列化对象
 oos.writeObject(user); //关闭流
 oos.close(); socket.close(); } catch (Exception e) { e.printStackTrace(); } } }