十三、Socket編程實現TCP和UDP

1.TCP

（1）TCPServer.java類

package com.interview.javabasic.socket;

import com.interview.javabasic.thread.MyThread;

import java.net.ServerSocket;
import java.net.Socket;

public class TCPServer {
    public static void main(String[] args) throws Exception {
        //創建socket,並將socket綁定到65000端口
 

        ServerSocket ss = new ServerSocket(65000);
        //死循環，使得socket一直等待並處理客戶端發送過來的請求
        while (true) {
            //監聽65000端口，直到客戶端返回連接信息後才返回
            Socket socket = ss.accept();
            //獲取客戶端的請求信息後，執行相關業務邏輯
            new LengthCalculator(socket).start();
        }
    }
}

（2）TCPClient.java

package com.interview.javabasic.socket;

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

public class TCPClient {
    public static void main(String[] args) throws Exception {
        //創建socket，並指定連接的是本機的端口號為65000的服務器socket
        Socket socket = new Socket("127.0.0.1", 65000);
        
 
//獲取輸出流
        OutputStream os = socket.getOutputStream();
        //獲取輸入流
        InputStream is = socket.getInputStream();
        //將要傳遞給server的字符串參數轉換成byte數組，並將數組寫入到輸出流中
        os.write(new String("hello world").getBytes());
        int ch = 0;
        byte[] buff = new byte[1024];
        //buff主要用來讀取輸入的內容，存成byte數組，ch主要用來獲取讀取數組的長度
        ch = is.read(buff);
        //將接收流的byte數組轉換成字符串，這裏是從服務端回發回來的字符串參數的長度
        String content = new String(buff, 0, ch);
        System.out.println(content);
        //不要忘記關閉輸入輸出流以及socket
        is.close();
        os.close();
        socket.close();
    }
}

（3）LengthCalculator.java

package com.interview.javabasic.socket;

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

public class LengthCalculator extends Thread {
    //以socket為成員變量
    private Socket socket;

    public LengthCalculator(Socket socket) {
        this.socket = socket;
    }

    @Override
    public void run() {
        try {
            //獲取socket的輸出流
            OutputStream os = socket.getOutputStream();
            //獲取socket的輸入流
            InputStream is = socket.getInputStream();
            int ch = 0;
            byte[] buff = new byte[1024];
            //buff主要用來讀取輸入的內容，存成byte數組，ch主要用來獲取讀取數組的長度
            ch = is.read(buff);
            //將接收流的byte數組轉換成字符串，這裏獲取的內容是客戶端發送過來的字符串參數
            String content = new String(buff, 0, ch);
            System.out.println(content);
            //往輸出流裏寫入獲得的字符串的長度，回發給客戶端
            os.write(String.valueOf(content.length()).getBytes());
            //不要忘記關閉輸入輸出流以及socket
            is.close();
            os.close();
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

2.UDP

（1）UDPServer.java

package com.interview.javabasic.socket;

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

public class UDPServer {
    public static void main(String[] args) throws Exception {
        // 服務端接受客戶端發送的數據報
        //監聽的端口號
        DatagramSocket socket = new DatagramSocket(65001);
        //存儲從客戶端接受到的內容
        byte[] buff = new byte[100];
        DatagramPacket packet = new DatagramPacket(buff, buff.length);
        //接受客戶端發送過來的內容，並將內容封裝進DatagramPacket對象中
        socket.receive(packet);
        //從DatagramPacket對象中獲取到真正存儲的數據
        byte[] data = packet.getData();
        //將數據從二進制轉換成字符串形式
        String content = new String(data, 0, packet.getLength());
        System.out.println(content);
        //將要發送給客戶端的數據轉換成二進制
        byte[] sendedContent = String.valueOf(content.length()).getBytes();
        // 服務端給客戶端發送數據報
        //從DatagramPacket對象中獲取到數據的來源地址與端口號
        DatagramPacket packetToClient = new DatagramPacket(sendedContent,
                sendedContent.length, packet.getAddress(), packet.getPort());
        //發送數據給客戶端
        socket.send(packetToClient);
    }

}

（2）UDPClient.java

package com.interview.javabasic.socket;

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

public class UDPClient {
    public static void main(String[] args) throws Exception {
        // 客戶端發數據報給服務端
        DatagramSocket socket = new DatagramSocket();
        // 要發送給服務端的數據
        byte[] buf = "Hello World".getBytes();
        // 將IP地址封裝成InetAddress對象
        InetAddress address = InetAddress.getByName("127.0.0.1");
        // 將要發送給服務端的數據封裝成DatagramPacket對象 需要填寫上ip地址與端口號
        DatagramPacket packet = new DatagramPacket(buf, buf.length, address,
                65001);
        // 發送數據給服務端
        socket.send(packet);

        // 客戶端接受服務端發送過來的數據報
        byte[] data = new byte[100];
        // 創建DatagramPacket對象用來存儲服務端發送過來的數據
        DatagramPacket receivedPacket = new DatagramPacket(data, data.length);
        // 將接受到的數據存儲到DatagramPacket對象中
        socket.receive(receivedPacket);
        // 將服務器端發送過來的數據取出來並打印到控制臺
        String content = new String(receivedPacket.getData(), 0,
                receivedPacket.getLength());
        System.out.println(content);

    }

}

計算機網絡（十三），Socket編程實現TCP和UDP