网络编程示例

TCP实现发送信息

//客户端
package com.netPro.tcpCommunicate;

import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;

public class TClient {
    public static void main(String[] args) throws Exception {
        //客户端
        //要知道服务器的地址和端口号
        InetAddress serverIP = InetAddress.getByName("127.0.0.1");
        int port = 8888;
        //创建socket连接
        Socket socket = new Socket(serverIP, port);
        //发送消息 IO流
        OutputStream os = socket.getOutputStream();
        os.write("你好，客户端向你发送了一条消息！".getBytes());
        System.out.println("发送完毕！");

        os.close();
        socket.close();
    }
}

//服务器
package com.netPro.tcpCommunicate;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class TServer {
    public static void main(String[] args) throws IOException {
        //服务端
        //有个地址
        ServerSocket serverSocket = new ServerSocket(8888);
        //等待客户端连接
        Socket socket = serverSocket.accept();
        //读取消息
        InputStream is = socket.getInputStream();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] date = new byte[1024];
        int count = 0;
        while ((count = is.read(date)) != -1){
            baos.write(date,0,count);
        }
        System.out.println(baos.toString());

        baos.close();
        is.close();
        socket.close();
        serverSocket.close();
    }
}

TCP实现上传文件

//客户端
package com.netPro.tcpFileDown;

import java.io.*;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

public class TClient {
    public static void main(String[] args) {
        try {
            InetAddress serverIP = InetAddress.getByName("127.0.0.1");
            int port = 8088;
            //创建socket服务
            Socket socket = new Socket(serverIP,port);
            //创建一个输出流
            OutputStream os = socket.getOutputStream();
            //读取文件
            FileInputStream fis = new FileInputStream(new File("1.jpg"));
            byte[] date = new byte[1024];
            int count;
            while ((count=fis.read(date)) != -1){
                os.write(date,0,count);
            }

            //通知服务器我已经结束了
            socket.shutdownOutput();

            //确定服务器接收完毕 断开连接
            InputStream is = socket.getInputStream();
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            byte[] dates = new byte[1024];
            int counts;
            while ((counts = is.read(dates)) != -1){
                bos.write(dates,0,counts);
            }
            System.out.println(bos.toString());

            bos.close();
            is.close();
            fis.close();
            os.close();
            socket.close();

        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

//服务器
package com.netPro.tcpFileDown;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class TServer {
    public static void main(String[] args) {
        try {
            //创建服务
            ServerSocket serverSocket = new ServerSocket(8088);
            //阻塞式监听 一直等待
            Socket socket = serverSocket.accept();
            //获取输入流
            InputStream is = socket.getInputStream();
            //文件输出
            FileOutputStream fos = new FileOutputStream(new File("receive.jpg"));
            byte[] date = new byte[1024];
            int count;
            while ((count=is.read(date)) != -1){
                fos.write(date,0,count);
            }

            //通知客户端我已经接收完毕 可以断开了
            OutputStream os = socket.getOutputStream();
            os.write("我已经接收完毕，可以断开连接了".getBytes());

            os.close();
            fos.close();
            is.close();
            socket.close();
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

UDP实现发信息

//发送方
package com.netPro.UDPSendMesage;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;

public class ClientSend {
    public static void main(String[] args) {
        try {
            InetSocketAddress localhost = new InetSocketAddress("localhost",6666);
            DatagramSocket socket = new DatagramSocket(8888);
            while (true){
                //控制台输入数据
                BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
                String date = br.readLine();
                byte[] dates = date.getBytes();
                DatagramPacket packet = new DatagramPacket(dates,0,dates.length,localhost);

                socket.send(packet);
                if (date.equals("bye")){
                    break;
                }
            }
            socket.close();

        } catch (SocketException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

//接收方
package com.netPro.UDPSendMesage;

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

public class ClientReceive {
    public static void main(String[] args) {
        try {
            DatagramSocket socket = new DatagramSocket(6666);
            while (true){
                //准备接收数据
                byte[] date = new byte[1024];
                DatagramPacket packet = new DatagramPacket(date,0,date.length);
                socket.receive(packet);

                byte[] receive = packet.getData();
                System.out.println(new String(receive,0, packet.getLength()));

                if (receive.equals("bye")){
                    break;
                }

            }
            socket.close();
        } catch (SocketException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

UDP实现聊天功能

//发送方
package com.netPro.UDPChat;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;

public class EndSend extends JFrame implements Runnable{
    DatagramSocket socket = null;
    BufferedReader reader = null;
    InetSocketAddress toAddress = null;
    InputStreamReader isr = null;
    DatagramPacket packet = null;

    int fromPort;
    String toIP;
    int toPort;
    
    public EndSend(int fromPort, String toIP, int toPort){
        this.fromPort = fromPort;
        this.toIP = toIP;
        this.toPort = toPort;

        try {
            socket = new DatagramSocket(fromPort);
            isr = new InputStreamReader(System.in);
            reader = new BufferedReader(isr);
            toAddress = new InetSocketAddress(toIP,toPort);
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }


    @Override
    public void run() {
        while (true){
            try {
                String date = reader.readLine();
                byte[] dates = date.getBytes();
                packet = new DatagramPacket(dates,0,dates.length,toAddress);
                socket.send(packet);
                if (date.equals("bye")){
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        socket.close();
    }
}

//接收
package com.netPro.UDPChat;

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

public class EndReceive implements Runnable{
    DatagramSocket socket = null;
    DatagramPacket packet = null;
    int Port;
    String msgFrom;
    public EndReceive(){

    }

    public EndReceive(int Port,String msgFrom){
        this.Port = Port;
        this.msgFrom = msgFrom;
        try {
            socket = new DatagramSocket(this.Port);
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run() {
        while (true){
            try {
                byte[] date = new byte[1024];
                packet = new DatagramPacket(date,0,date.length);
                socket.receive(packet);
                byte[] receive = packet.getData();
                System.out.println(msgFrom+":"+new String(receive,0, packet.getLength()));

                if (receive.equals("bye")){
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

测试类

package com.netPro.UDPChat;

public class TestStudent {
    public static void main(String[] args) {
        new Thread(new EndSend(777,"127.0.0.1",888)).start();
        new Thread(new EndReceive(666,"teacher")).start();
    }
}

package com.netPro.UDPChat;

public class TestTeacher {
    public static void main(String[] args) {
        new Thread(new EndSend(555,"127.0.0.1",666)).start();
        new Thread(new EndReceive(888,"student")).start();
    }
}