Java编程

一、客户端(Client),服务器(Server)

1.Java编程的两个概念:ServerSocket,Server。

2.套接字Socket:服务端和客户端之间通过套接字Socket建立连接,然后进行通信。

3.ServerSocket和Server的用处:首先ServerSocket将在服务端监听某个端口，当发现客户端有Socket来试图连接它时，它会使用方法accept()来接收Socket的连接请求，同时在服务端建立一个对应的Socket与之进行通信。这样就有两个Socket了，客户端和服务端各一个。同时Socket与Socket之间是双向连通的。

二、客户端读写和服务器读写

服务端代码

package com.lovo.chat;

import java.awt.*;

import java.io.*;

import java.net.*;
import javax.swing.*;
public class Server extends JFrame {

    private JTextArea info;
    private Socket socket; 
//带c参的构造器
   public Server(String title) {
        super(title);

        setSize(200, 300);//设置窗口大小
 setLocation(200, 300); //设置坐标
       setDefaultCloseOperation(EXIT_ON_CLOSE);//终止程序
       info = new JTextArea();
        info.setEditable(false);//设置文本框是否能够编辑
       info.setFocusable(false);//设置是否聚集焦点
       JScrollPane jsp = new JScrollPane(info);//滚动面板
       this.add(jsp, BorderLayout.CENTER);

        JPanel pnl = new JPanel(new BorderLayout());
        final JTextField msg = new JTextField(); // 输入文本框
        JButton send = new JButton("发送");
        pnl.add(msg, BorderLayout.CENTER);
        pnl.add(send, BorderLayout.EAST);
        this.add(pnl, BorderLayout.SOUTH);

        setVisible(true);//设置是否窗口可见
        startServer();

        // 发送消息到客户端
        send.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                try {
                    BufferedOutputStream out = new BufferedOutputStream(socket
                            .getOutputStream());
                    out.write((msg.getText() + "
").getBytes());
                    out.flush();
                } catch (IOException ex) {
                    throw new RuntimeException(ex);
                }
            }
        });
    }

    private void startServer() {
        try {
            ServerSocket server = new ServerSocket(30001);
            socket = server.accept();
            // 从客户端读
            read();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private void read() {
        try {
            final BufferedReader reader = new BufferedReader(
                    new InputStreamReader(socket.getInputStream()));
            new Thread(new Runnable() {
                @Override
                public void run() {
                    char[] ch = new char[1024];
                    int len;
                    try {
                        while (-1 != (len = reader.read(ch))) {
                            info.append(new String(ch, 0, len));
                        }
                    } catch (IOException e) {
                        throw new RuntimeException(e);
                    }
                }
            }).start();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) {
        new Server("服务器");
    }
}

 客户端代码
package com.lovo.chat;

import java.awt.*;
import java.io.*;
import java.net.*;
import javax.swing.*;

public class Client extends JFrame {

    private JTextArea info;
    private Socket socket;

    public Client(String title) {
        super(title);

        setSize(200, 300);
        setLocation(600, 300);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        info = new JTextArea();
        info.setEditable(false);
        info.setFocusable(false);
        JScrollPane jsp = new JScrollPane(info);
        this.add(jsp, BorderLayout.CENTER);

        JPanel pnl = new JPanel(new BorderLayout());
        final JTextField msg = new JTextField();
        JButton send = new JButton("发送");

        pnl.add(msg, BorderLayout.CENTER);
        pnl.add(send, BorderLayout.EAST);
        this.add(pnl, BorderLayout.SOUTH);

        setVisible(true);

        startClient();

        // 发送消息到服务端
        send.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                try {
                    BufferedOutputStream out = new BufferedOutputStream(socket
                            .getOutputStream());//写入要输出的字符
                   out.write((msg.getText() + "
").getBytes());
                    out.flush();
                } catch (IOException ex) {
                    throw new RuntimeException(ex);
                }
            }
        });
    }

    private void startClient() {
        try {
            socket = new Socket("127.0.0.1", 30001);//设置IP地址和端口号
            // 从服务器读
            read();
        } catch (UnknownHostException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private void read() {
        try {
            final BufferedReader reader = new BufferedReader(
                    new InputStreamReader(socket.getInputStream()));
            new Thread(new Runnable() {
                @Override
                public void run() {
                    char[] ch = new char[1024];
                    int len;
                    try {
                        while (-1 != (len = reader.read(ch))) {
                            info.append(new String(ch, 0, len));
                        }
                    } catch (IOException e) {
                        throw new RuntimeException(e);
                    }
                }
            }).start();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) {
        new Client("客户端");//设置客户端标题
   }
}