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 3 192.168.3.51PING 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 ms64 bytes from 192.168.3.51: icmp_seq=2 ttl=64 time=0.332 ms64
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 2000msrtt 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 3 192.168.3.52PING 192.168.3.52 (192.168.3.52) 56(84) bytes of data.From 192.168.7.181 icmp_seq=1 Destination Host UnreachableFrom 192.168.7.181 icmp_seq=2
Destination Host UnreachableFrom 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。