[网络协议]Day 227 网络编程（3）

网络编程（3）

UDP实现简单的聊天

接收端

package com.yangxu.chat;

import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class UdpReceiver {
    public static void main(String[] args) throws Exception {
        DatagramSocket socket = new DatagramSocket(6666);
        while (true){
            byte[] bytes = new byte[1024];
            DatagramPacket packet = new DatagramPacket(bytes,0,bytes.length);
            socket.receive(packet);
            byte[] data = packet.getData();
            String receive = new String(data, 0, packet.getLength());
            System.out.println(receive);
            if (receive.equals("bye")){
                break;
            }
        }
        socket.close();

    }
}

发送端

package com.yangxu.chat;

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

public class UdpSender {
    public static void main(String[] args) throws Exception {
        DatagramSocket socket = new DatagramSocket(8888);
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        while (true){
            String s = reader.readLine();
            byte[] bytes = s.getBytes();
            DatagramPacket packet = new DatagramPacket(bytes,0,bytes.length,new InetSocketAddress("localhost",6666));
            socket.send(packet);
            if (s.equals("bye")){
                break;
            }
        }
        socket.close();

    }
}

UDP实现简单“在线咨询”

老师的“客户端”

package com.yangxu.chat2;

public class ChatOfTeacher {
    public static void main(String[] args) {
        new Thread(new ChatSender("localhost",8888,6666)).start();
        new Thread(new ChatReceive("学生",7777)).start();
    }
}

学生的“客户端”

package com.yangxu.chat2;

public class ChatOfStudent {
    public static void main(String[] args) {
        new Thread(new ChatSender("localhost",7777,5555)).start();
        new Thread(new ChatReceive("老师",8888)).start();
    }
}

发送端

package com.yangxu.chat2;

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 ChatSender implements Runnable{
    DatagramSocket socket = null;
    BufferedReader reader = null;
    private String toIP;
    private int toPort;
    private int fromPort;
    public ChatSender(String toIP, int toPort, int fromPort) {
        this.toIP = toIP;
        this.toPort = toPort;
        this.fromPort = fromPort;
        try {
            socket = new DatagramSocket(fromPort);
        } catch (SocketException e) {
            e.printStackTrace();
        }
        reader = new BufferedReader(new InputStreamReader(System.in));
    }

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

接收端

package com.yangxu.chat2;

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

public class ChatReceive implements Runnable{
    DatagramSocket socket = null;
    private int port;
    private String name;

    public ChatReceive(String name, int port) {
        this.port = port;
        this.name = name;
        try {
            socket = new DatagramSocket(port);
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run() {
        while (true){
            try {
                byte[] bytes = new byte[1024];
                DatagramPacket packet = new DatagramPacket(bytes,0,bytes.length);
                socket.receive(packet);
                byte[] data = packet.getData();
                String receive = new String(data, 0, packet.getLength());
                System.out.println(name+"："+receive);
                if (receive.equals("bye")){
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        socket.close();

    }
}

URL

定义啥的建议参考《计算机网络技术》就大学厚厚的红色那本书

用TomCat下载网易云歌曲千千阙歌

package com.yangxu.url;

import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class UrlDownLoad {
    public static void main(String[] args) throws Exception {
        URL url = new URL("https://m804.music.126.net/20220304194033/c8b3c4167301017e5f6a7980d308a30b/jdyyaac/5153/020b/070f/f96cdc5c8e5ae945924f0ec513061b98.m4a?authSecret=0000017f54a4608b1ae60aaba035f194");
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        InputStream inputStream = urlConnection.getInputStream();
        FileOutputStream fos = new FileOutputStream("test.m4a");
        byte[] bytes = new byte[1024];
        int len;
        while ((len=inputStream.read(bytes))!=-1){
            fos.write(bytes,0,len);
        }
        urlConnection.disconnect();
        inputStream.close();
        fos.close();
    }
}