Java命令行如何网络通信

在Java中，你可以使用多种方法进行网络通信。以下是一些基本的方法：

1. 使用java.net.Socket和java.net.ServerSocket类进行TCP通信。

客户端示例：

import java.io.*;
import java.net.*;

public class TCPClient {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("localhost", 8080);
        OutputStream output = socket.getOutputStream();
        PrintWriter writer = new PrintWriter(output, true);

        writer.println("Hello, Server!");
        socket.close();
    }
}

服务器端示例：

import java.io.*;
import java.net.*;

public class TCPServer {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8080);
        Socket socket = serverSocket.accept();
        InputStream input = socket.getInputStream();
        BufferedReader reader = new BufferedReader(new InputStreamReader(input));

        String message = reader.readLine();
        System.out.println("Client says: " + message);
        socket.close();
        serverSocket.close();
    }
}

2. 使用java.net.DatagramSocket和java.net.DatagramPacket类进行UDP通信。

客户端示例：

import java.io.*;
import java.net.*;

public class UDPClient {
    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket();
        InetAddress address = InetAddress.getByName("localhost");
        byte[] buffer = "Hello, Server!".getBytes();

        DatagramPacket packet = new DatagramPacket(buffer, buffer.length, address, 8080);
        socket.send(packet);
        socket.close();
    }
}

服务器端示例：

import java.io.*;
import java.net.*;

public class UDPServer {
    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket(8080);
        byte[] buffer = new byte[1024];

        DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
        socket.receive(packet);

        String message = new String(packet.getData(), 0, packet.getLength());
        System.out.println("Client says: " + message);
        socket.close();
    }
}

这些示例展示了如何在Java中使用命令行进行基本的网络通信。你可以根据自己的需求修改这些示例，以实现更复杂的功能。