Java中TCP和UDP的helloworld-优快云博客

本文提供了一个简单的TCP客户端和服务端实现示例，用于发送和接收消息，同时展示了UDP一对一通信的基本流程，包括设置超时时间和数据包的发送与接收。

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TCP

服务端：

package com.ysdx.socket1;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class S1Impl0 implements ISocket1 {

    ServerSocket server;
    Socket socket;
    PrintWriter writer;
    BufferedReader reader;
    @Override
    public void work() {
        try {
            server=new ServerSocket(5001);
            socket=server.accept();
            writer = new PrintWriter(socket.getOutputStream());
            reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            String message=reader.readLine();
            if (message!=null) {
                System.out.println(message);
            } else {
                System.out.println("No Message Here!");
            }
            writer.close();
            reader.close();
            socket.close();
            server.close();
            
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

客户端：

package com.ysdx.socket0;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

public class S0Impl0 implements ISocket0 {

    Socket socket;
    PrintWriter writer;
    BufferedReader reader;

    @Override
    public void work() {
        try {
            socket = new Socket("127.0.0.1", 5001);
            writer = new PrintWriter(socket.getOutputStream());
            reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            writer.write("hello !");
            writer.flush();
            writer.close();
            reader.close();
            socket.close();
        } catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        

    }

}

UDP

一对一，需要选择合适的超时时间

package com.ysdx.udp0;

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

public class UDP0 {

    
    public static void main(String[] args) throws IOException {
        InetSocketAddress address;
        DatagramPacket packet;
        DatagramSocket socket;
        byte []buffer=new byte[1024];
        
        address=new InetSocketAddress("localhost", 5002);
        socket=new DatagramSocket(address);
        socket.setSoTimeout(60000);
        packet=new DatagramPacket(buffer, buffer.length);
        socket.receive(packet);
        String message=new String(packet.getData(), 0, packet.getLength());
        System.out.println(message);
//        String reply="OK";
        byte[] reply="OK".getBytes();
        packet=new DatagramPacket(buffer, buffer.length, packet.getAddress(), packet.getPort());
        packet.setData(reply);
        socket.send(packet);
        socket.close();
        
    }
}

package com.ysdx.udp1;

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

public class UDP1 {

    public static void main(String[] args) throws IOException {
        InetSocketAddress address;
        DatagramPacket packet;
        DatagramSocket socket;
        byte []buffer=new byte[1024];
        
        
        socket=new DatagramSocket();
        socket.setSoTimeout(60000);
        
        byte[] reply="Hello".getBytes();
        packet=new DatagramPacket(buffer, buffer.length, InetAddress.getByName("localhost"), 5002);
        packet.setData(reply);
        socket.send(packet);
        
        packet=new DatagramPacket(buffer, buffer.length);
        socket.receive(packet);
        String message=new String(packet.getData(), 0, packet.getLength());
        System.out.println(message);
//        String reply="OK";
        
        
        socket.close();
        
    }
}