请用java语言socket下模拟实现Ping程序默认参数功能

以下是使用 Java Socket 实现 Ping 程序默认参数的示例代码：

import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

public class PingProgram {
    public static void main(String[] args) {
        String hostName = "localhost"; // 默认主机名
        int portNumber = 80; // 默认端口号

        try (Socket socket = new Socket(hostName, portNumber)) {
            InetAddress address = socket.getInetAddress();
            System.out.println("Pinging " + address.getHostAddress() + " with 32 bytes of data:");

            // 发送 4 个 ping 请求
            for (int i = 0; i < 4; i++) {
                long startTime = System.currentTimeMillis();
                socket.getOutputStream().write(("Ping " + i + " " + startTime + "\n").getBytes());
                socket.getOutputStream().flush();

                // 接收 ping 响应
                byte[] buffer = new byte[1024];
                int bytesRead = socket.getInputStream().read(buffer);
                String response = new String(buffer, 0, bytesRead);
                System.out.println("Received ping response: " + response.trim());

                // 计算响应时间
                long endTime = System.currentTimeMillis();
                long duration = endTime - startTime;
                System.out.println("Ping response time: " + duration + "ms");
            }
        } catch (UnknownHostException e) {
            System.err.println("Unknown host: " + hostName);
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to " + hostName);
            System.exit(1);
        }
    }
}

该程序使用 Java Socket 连接到默认主机名和端口号，并发送 4 个 ping 请求。每个 ping 请求包含一个序号和发送时间戳。程序等待响应并计算响应时间。注意，该程序仅模拟了 ping 功能，而不是使用 ICMP 协议直接发送 ping 请求。