linux机器上执行ping命令的java方法

在编写网管系统的过程中，经常需要判断某台机器是否可用，于是采用使用ping机器的方法判断该机器当前是否可用，方法如下：

/**
	 * @Title: execPingCommand
	 * @Description: 执行ping命令，查看设备是否可用
	 * @param @param deviceIp
	 * @return boolean true-能ping通，false-不能ping通
	 * @throws
	 */
	public static boolean execPingCommand(String deviceIp) {
		logger.debug("enter VolumeManage.execPingCommand(String deviceIp) ");
		boolean networkUseable = false;
		// String address="www.javawind.net";
		Process process = null;
		try {
			process = Runtime.getRuntime().exec("ping -c 3 " + deviceIp);
		} catch (IOException e1) {
			logger.error("System error: ", e1);
		}
		InputStreamReader r = new InputStreamReader(process.getInputStream());
		LineNumberReader returnData = new LineNumberReader(r);

		String returnMsg = "";
		String line = "";
		try {
			while ((line = returnData.readLine()) != null) {
				// System.out.println(line);
				returnMsg += line;
			}

			if (returnMsg.indexOf("Unreachable") != -1
					|| returnMsg.indexOf("100% packet loss") != -1) {
				networkUseable = false;
			} else {
				networkUseable = true;
			}
		} catch (IOException e) {
			logger.error("System error: ", e);
		} finally {
			if (returnData != null) {
				try {
					returnData.close();

				} catch (IOException e) {
					// TODO Auto-generated catch block
					logger.error("System error: ", e);
				}
			}
			if (r != null) {
				try {
					r.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					logger.error("System error: ", e);
				}
			}
		}
		logger.debug("exit VolumeManage.execPingCommand(String deviceIp) "
				+ "[networkUseable] = " + networkUseable);
		return networkUseable;
	}

 此方法关键命令为红色部分：ping -c 3 + ip;这个命令为linux系统所有，windows上不能执行，表示方法执行之后，只需要返回3行响应消息便可，不然在linux中，如果不终止该命令，会不停的打印响应的消息。

ping通机器的响应消息如下：

[root@abc ~]# ping -c 3 192.168.3.51
PING 192.168.3.51 (192.168.3.51) 56(84) bytes of data.
64 bytes from 192.168.3.51: icmp_seq=1 ttl=64 time=14.6 ms
64 bytes from 192.168.3.51: icmp_seq=2 ttl=64 time=0.332 ms
64 bytes from 192.168.3.51: icmp_seq=3 ttl=64 time=0.359 ms

--- 192.168.3.51 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2000ms
rtt min/avg/max/mdev = 0.332/5.103/14.619/6.728 ms
[root@abc ~]#

 

ping不同的机器的响应消息如下：

[root@abc ~]# ping -c 3 192.168.3.52
PING 192.168.3.52 (192.168.3.52) 56(84) bytes of data.
From 192.168.7.181 icmp_seq=1 Destination Host Unreachable
From 192.168.7.181 icmp_seq=2 Destination Host Unreachable
From 192.168.7.181 icmp_seq=3 Destination Host Unreachable

--- 192.168.3.52 ping statistics ---
3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 2000ms, pipe 3
[root@abc ~]#

因此，方法根据这两个条件进行判断，如果含有Unreachable或者100% packet loss就表示机器ping不同，不可用，否则为可用。