Pinging一台机器会把它唤醒吗?

时间:2017-07-24 15:38:53

标签: java ip wake-on-lan

我有一个代码来检查机器是否存活。

InetAddress.getByName(IPADDRESS).isReachable(TIMEOUT);

这个请求会唤醒机器吗?或者只是给出一个不关机或无法访问的状态。

1 个答案:

答案 0 :(得分:1)

不,简单的ping命令无论其配置如何都不会唤醒您的计算机。你会想要使用"唤醒兰"命令,其中必须包含机器的MAC地址,IP地址本身是不够的。此外,机器必须支持该功能(更确切地说,网络适配器必须使用),并且必须启用它,因此请确保完成。

我包括过去曾提到的关于如何在java中实现这个的示例:

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

public class WakeOnLan {

public static final int PORT = 9;    

public static void main(String[] args) {

    if (args.length != 2) {
        System.out.println("Usage: java WakeOnLan <broadcast-ip> <mac-address>");
        System.out.println("Example: java WakeOnLan 192.168.0.255 00:0D:61:08:22:4A");
        System.out.println("Example: java WakeOnLan 192.168.0.255 00-0D-61-08-22-4A");
        System.exit(1);
    }

    String ipStr = args[0];
    String macStr = args[1];

    try {
        byte[] macBytes = getMacBytes(macStr);
        byte[] bytes = new byte[6 + 16 * macBytes.length];
        for (int i = 0; i < 6; i++) {
            bytes[i] = (byte) 0xff;
        }
        for (int i = 6; i < bytes.length; i += macBytes.length) {
            System.arraycopy(macBytes, 0, bytes, i, macBytes.length);
        }

        InetAddress address = InetAddress.getByName(ipStr);
        DatagramPacket packet = new DatagramPacket(bytes, bytes.length, address, PORT);
        DatagramSocket socket = new DatagramSocket();
        socket.send(packet);
        socket.close();

        System.out.println("Wake-on-LAN packet sent.");
    }
    catch (Exception e) {
        System.out.println("Failed to send Wake-on-LAN packet: + e");
        System.exit(1);
    }

}

private static byte[] getMacBytes(String macStr) throws IllegalArgumentException {
    byte[] bytes = new byte[6];
    String[] hex = macStr.split("(\\:|\\-)");
    if (hex.length != 6) {
        throw new IllegalArgumentException("Invalid MAC address.");
    }
    try {
        for (int i = 0; i < 6; i++) {
            bytes[i] = (byte) Integer.parseInt(hex[i], 16);
        }
    }
    catch (NumberFormatException e) {
        throw new IllegalArgumentException("Invalid hex digit in MAC address.");
    }
    return bytes;
}


}