这里用 sh -c "命令" 的方式是因为java里只能这么用，管道这边java处理不了，所以只能一次执行一条命令，但是在linux里用 sh -c 的方式返回的awk处理过的结果是有问题的，比如下面：

[root@ ~]# sh -c "ping www.baidu.com -c 3 | awk -F '[ ]+' 'NR==8 {print $4}'"
rtt min/avg/max/mdev = 3.514/3.778/4.232/0.329 ms

但是在java代码里却能够成功执行所需要的功能，可能是java执行后产生的是下面这样的效果：

[root@ ~]# ping www.baidu.com -c | awk -F '[ ]+' 'NR==8 {print $4}'
2.586/4.436/6.657/1.683

下面的java代码能够在 CentOS Linux release 7.6.1810 (Core) 下实现效果（取得ms值）：

package com.kinome.surveillance.detect.connectivity;

public class UpDateConnectivity {

public static String upDateConnectivity(int rid, String ptLink) {

    String targetUrl = FilterHttpHeader.filterHttpHeader(ptLink);  
    String canPingTargetUrl = ConnectionTimeMatchHandler.getFilteredResult(targetUrl, "(.\*?)/");  

// String TimeLine = RunCmdGetConnectionTimeHandler.getAverageTimeLine(canPingTargetUrl);
// String connectTime = ConnectionTimeMatchHandler.getFilteredResult(TimeLine, "平均 = (.*?)ms").toString();
String avg1 = RunCmdGetConnectionTimeHandler.fetchAvg1(canPingTargetUrl);
String connectTime = RunCmdGetConnectionTimeHandler.fetchAvg2(avg1);
System.out.println("avg = " + connectTime + " ms");
return connectTime;
}
}

public static String fetchAvg1(String targetUrl) {
BufferedReader br = null;
String result = null;
try {
List cmds = new LinkedList();
cmds.add("sh");
cmds.add("-c");
cmds.add("ping " + targetUrl + " -c 3 | awk -F '[ ]+' 'NR==8 {print $4}'");
ProcessBuilder pb = new ProcessBuilder(cmds);
pb.redirectErrorStream(true);
Process p = pb.start();
p.waitFor(3, TimeUnit.SECONDS);
br = new BufferedReader(new InputStreamReader(p.getInputStream()));
StringBuffer sb = new StringBuffer();
String line;
while ((line = br.readLine()) != null) {
sb.append(line);
}
result = sb.toString();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
return result;
}

public static String fetchAvg2(String avg1) {  
    BufferedReader br = null;  
    String result = null;  
    try {  
        List<String> cmds = new LinkedList<String>();  
        cmds.add("sh");  
        cmds.add("-c");  
        cmds.add("echo " + avg1 + " | awk  -F '\[/\]+' '{print $2}'");  
        ProcessBuilder pb = new ProcessBuilder(cmds);  
        pb.redirectErrorStream(true);  
        Process p = pb.start();  
        p.waitFor(3, TimeUnit.SECONDS);  
        br = new BufferedReader(new InputStreamReader(p.getInputStream()));  
        StringBuffer sb = new StringBuffer();  
        String line;  
        while ((line = br.readLine()) != null) {  
            sb.append(line);  
        }  
        result = sb.toString();  
    } catch (Exception e) {  
        e.printStackTrace();  
    } finally {  
        if (br != null) {  
            try {  
                br.close();  
            } catch (Exception e) {  
                e.printStackTrace();  
            }  
        }  
    }  
    return result;  
}