Java命令行如何进行网络操作

在Java命令行中进行网络操作，你可以使用Java标准库中的java.net包。这个包提供了一系列类和接口，用于实现网络应用程序。以下是一些基本的网络操作示例：

1. 使用InetAddress类获取IP地址和主机名：

import java.net.InetAddress;
import java.net.UnknownHostException;

public class NetworkOperations {
    public static void main(String[] args) {
        try {
            InetAddress ipAddress = InetAddress.getByName("www.example.com");
            System.out.println("IP Address: " + ipAddress.getHostAddress());
            System.out.println("Hostname: " + ipAddress.getHostName());
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }
}

2. 使用URL和URLConnection类读取网页内容：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

public class NetworkOperations {
    public static void main(String[] args) {
        try {
            URL url = new URL("https://www.example.com");
            URLConnection connection = url.openConnection();
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                System.out.println(inputLine);
            }
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

3. 使用Socket类实现客户端与服务器的通信：

客户端：

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

public class Client {
    public static void main(String[] args) {
        try {
            Socket socket = new Socket("localhost", 8080);
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            out.println("Hello, Server!");
            System.out.println("Server response: " + in.readLine());

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

服务器：

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 Server {
    public static void main(String[] args) {
        try {
            ServerSocket serverSocket = new ServerSocket(8080);
            System.out.println("Server is listening on port 8080...");

            Socket socket = serverSocket.accept();
            System.out.println("New client connected.");

            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

            String message = in.readLine();
            System.out.println("Client message: " + message);

            out.println("Hello, Client!");

            in.close();
            out.close();
            socket.close();
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

这些示例展示了如何在Java命令行中进行基本的网络操作。你可以根据自己的需求修改这些示例，实现更复杂的网络功能。