用Java实现聊天程序

package cn.com;


import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.Scanner;

public class Send {

    public static void main(String[] args) throws IOException {
        @SuppressWarnings("resource")
        DatagramSocket ds = new DatagramSocket();
        Scanner sc = new Scanner(System.in);
        String line = null;
        while ((line = sc.nextLine()) != null) {
            byte[] buf = line.getBytes();
            int length = buf.length;
            InetAddress address = InetAddress.getByName("1-PC21");//主机名
            DatagramPacket dp = new DatagramPacket(buf, length, address, 10086);   //10086为自己设置的端口号
            ds.send(dp);
        }
        sc.close();
    }

}

package cn.com;


import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class Receive {

    public static void main(String[] args) throws IOException {
        @SuppressWarnings("resource")
        DatagramSocket ds = new DatagramSocket(10086);//端口号需一致

        while (true) {
            byte[] b = new byte[1024 * 1];
            int length = b.length;
            DatagramPacket dp = new DatagramPacket(b, length);
            ds.receive(dp);

            byte[] data = dp.getData();
            int length2 = dp.getLength();
            String hostAddress = dp.getAddress().getHostAddress();
            String s = new String(data, 0, length2);
            System.out.println(s + "来自" + hostAddress);
        }

    }

}

package cn.com;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.util.Scanner;

public class Client {

    public static void main(String[] args) throws IOException {
        InetAddress address = InetAddress.getByName("1-PC21");//主机名
        int port = 10089;

        Scanner sc = new Scanner(System.in);
        String line = null;
        while ((line = sc.nextLine()) != null) {
            @SuppressWarnings("resource")
            Socket socket = new Socket(address, port);   //socket要在循环体中定义
            OutputStream os = socket.getOutputStream();
            os.write(line.getBytes());

            // 客户端接收服务端返回的消息(输入流)
            InputStream is = socket.getInputStream();
            byte[] b = new byte[1024 * 1];
            int len = is.read(b);
            String s = new String(b, 0, len);
            System.out.println(s);
        }
        sc.close();

    }

}

package cn.com;


import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

    public static void main(String[] args) throws IOException {
        @SuppressWarnings("resource")
        ServerSocket ss = new ServerSocket(10089);

        while (true) {
            Socket accept = ss.accept();    //循环中用到accept，所以要在循环中新建定义
            InputStream is = accept.getInputStream();
            byte[] b = new byte[1024 * 1];
            int len = is.read(b);
            String s = new String(b, 0, len);
            System.out.println("已接收客户端内容-->" + s);

            // 给客户端返回数据
            OutputStream os = accept.getOutputStream();
            String content = "客户端接收成功";
            os.write(content.getBytes());

            os.close();
            is.close();
            accept.close();
        }

    }

}