java inetaddress isreachable显示意外结果 [英] java inetaddress isreachable showing unexpected results

问题描述

我试图在每10秒钟内循环ping 200个IP。因此，此循环每10秒执行一次。我正在使用此代码来ping IP.

I am trying to ping 200s of IPs in a loop in every 10 seconds. So, this loop gets executed in every 10 seconds. I was using this code to ping the IPs

for (i = 0; i <= 200; i++ )
{
   ProcessBuilder processBuilder = new ProcessBuilder("ping", isWindows? "-n" : "-c", "1", *SOMEIP*);
   Process proc = processBuilder.start();

   int returnVal = proc.waitFor();
}

这只是我代码的一部分。我正在为每个ping创建单独的线程，因为如果100个IP关闭，那么ping每个并且需要超过300秒。每个IP顺序。所以，创建了单独的线程。但问题是，无论何时执行循环，PC的CPU使用率都会达到90％，这对关键系统来说并不好。所以我把程序更改为这个。

This is just the part of my code. I am creating separate thread for every ping because if 100 IPs are down, then it will take more than 300 seconds to ping each & every IP sequentially. So, created separate threads. But the problem was that whenever the loop gets executed, then the PCs CPU usage reaches to 90%, which is not good for a critical system. So I change the program to this one.

for (i = 0; i <= 200; i++ )
{
   InetAddress inet = InetAddress.getByName(*SOMEIP*);
   System.out.println(inet.isReachable(3000) ? "Host is reachable" : "Host is NOT reachable");

}

在上面的代码中，由于同样的问题，我正在为每个Ping创建单独的线程。现在，我在这里遇到另一个问题。此代码给出了意想不到的结果。可ping的IP有时也使用上面的代码显示无法访问。为什么会这样？



这个问题还有其他解决方案吗？



谢谢

In the above code also, I am creating separate thread for each Ping because of the same problem. Now, here I am getting another problem. This code is giving unexpected result. The IPs which are pingable are also showing not reachable sometimes using above code. Why this is happening ?

Is there any other solution to this problem ?

Thanks

推荐答案

请参阅 https://docs.oracle.com/javase/1.5.0/docs/api/java/net/InetAddress.html#isReachable（int） [ ^ ] 。你究竟想要实现什么目标？

See the comments at https://docs.oracle.com/javase/1.5.0/docs/api/java/net/InetAddress.html#isReachable(int)[^]. What exactly are you trying to achieve?

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