Java网络编程例Socket

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;


public class Server {
    ServerSocket serverSocket=null;
    public Server(){
        try{
            //注意，请下一次运行前关闭所有程序，否则端口号被JVM占用，将出错
            serverSocket=new ServerSocket(4115);
        }catch (Exception e) {
            e.printStackTrace();
        }
    }
    public void ready(){
        Socket you=null;
        while(true){
            try{
                you=serverSocket.accept(); //等待
                if(you!=null)
                    new ServerThread(you).start(); //为每一个客户建立一个处理线程
            }catch (Exception e) {
                // TODO: handle exception
                e.printStackTrace();
                continue;
            }
            
        }
    }

    public static void main(String[] args) {
        Server server=new Server();
        //在另一个线程里启动Client
        Thread thread=new Thread(
                new Runnable(){
                    public void run() {
                        // TODO Auto-generated method stub
                        Client client=new Client();
                        //try{Thread.sleep(1000);}catch (Exception e) {
// TODO: handle exception
//}
                    }
                });
        thread.start();
        server.ready();
        
    }
    class ServerThread extends Thread{
        Socket socket;
        DataOutputStream out=null;
        DataInputStream in=null;
        String s=null;
        public ServerThread(Socket t) {
            // TODO Auto-generated constructor stub
            socket=t;
            try{
                in=new DataInputStream(socket.getInputStream());
                out=new DataOutputStream(socket.getOutputStream());
            }catch (Exception e) {
                // TODO: handle exception
            }
        }
        @Override
        public void run() {
            while(true){
                try{
                    String s=in.readUTF();
                    System.out.println("服务器端收到："+s);
                    String send="服务器发送当前服务器时间："+new Date();
                    out.writeUTF(send);
                }catch (Exception e) {
                    // TODO: handle exception
                    System.out.println("客户离开");
                    break;
                }
            }
        }
    }
}

服务器端程序与客户端程序，直接运行Server.java

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;

import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;


public class Client extends JFrame 
    implements Runnable,ActionListener{
    Socket socket=null;
    JButton connBtn,sendBtn;
    JTextField input;
    JTextArea showArea;
    DataInputStream in=null;
    DataOutputStream out=null;
    Thread thread=null;
    boolean threadB=true;
    public Client(){
        socket=new Socket();
        connBtn=new JButton("连接服务器");
        
        sendBtn=new JButton("发送");
        sendBtn.setEnabled(false); //未连接之前不可用
        showArea=new JTextArea(8,18);
        input=new JTextField(12);
        Container container=getContentPane();
        container.setLayout(new FlowLayout());
        container.add(connBtn);
        container.add(input);
        container.add(sendBtn);
        container.add(new JScrollPane(showArea));
        sendBtn.addActionListener(this);
        connBtn.addActionListener(this);
        
        thread=new Thread(this);  //创建线程
        setBounds(100, 100, 360, 310);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    public void run() {
        // TODO Auto-generated method stub
        while(threadB){    //探测服务器端是否发来数据
            try{
                String s=in.readUTF();//取到数据之前堵塞
                showArea.append("接收到："+s+"\n");
                showArea.setCaretPosition(showArea.getText().length());
            }catch (Exception e) {
                // TODO: handle exception
                showArea.append("连接已断开");
                sendBtn.setEnabled(false);
                break; //终止线程
            }
        }
    }
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub
        if(e.getSource()==connBtn){  //连接服务器的按钮
            try{
                if(!socket.isConnected()){
                    InetAddress address=InetAddress.getByName("127.0.0.1");
                    InetSocketAddress socketAddress=new InetSocketAddress(address,4115); //端口号
                    socket.connect(socketAddress); //连接服务器
                    in=new DataInputStream(socket.getInputStream());
                    out=new DataOutputStream(socket.getOutputStream());
                    sendBtn.setEnabled(true);  //发送按钮可用
                    thread.start();         //线程启动，用于接收服务器端发来的消息并显示
                    
                }
            }catch (Exception ex) {
                // TODO: handle exception
                ex.printStackTrace();
                socket=new Socket();
            }
            
        }else if(e.getSource()==sendBtn){
            try{
                String s=input.getText();
                out.writeUTF(s);
            }catch (Exception ex) {
                ex.printStackTrace();
            }
        }
    }
    public static void main(String[] args) {
        Client client=new Client();
    }
}