Ping函数返回所有ping过的IP地址是可达的 [英] Ping function returns that all pinged IP addresses is reachable

问题描述

我打算ping从192.168.1.1到192.168.1.254的IP地址。首先，我使用的是InetAddress类，但它被窃听，有些IP地址即使是不可达也是如此。之后，我尝试了这种方法，它对单个IP工作非常好，但是当我把它放在for-loop里面的时候，所有ping到的IP都可以到达。你们可以告诉我这里有什么问题吗？

CODE：

  public class Main {
 public static void main（String [] args） {
 String ip =192.168.1。; 
尝试
 {
 for（int i = 0; i <= 254; i ++）{
 String ip2 = ip + i; 
 boolean reachable =（java.lang.Runtime.getRuntime（）。exec（ping -n 1+ ip2）.waitFor（）== 0）; 
 if（reachable）{
 System.out.println（IP is reachable ::+ ip2）; 
} 
 else {
 System.out.println（IP is nothable：+ ip2）; 
 
 $ b} catch（Exception e）
 {
 e.printStackTrace（）; 
 
 
 
 
 code $ 
 
 
 <编辑1：
 
 
 
我使用内置的Java函数来执行ping操作，但它不工作（再次）
 
 
这里是我使用的代码 
 
 
  import java.io.IOException; 
导入java.net.InetAddress; 
 import java.net.UnknownHostException; 
 public class Test {
 
 public static void main（String [] args）throws UnknownHostException，IOException {
 String ip =192.168.1.243; 
 InetAddress inet = InetAddress.getByName（ip）; 
 System.out.println（发送Ping请求到+ ip）; 
 if（inet.isReachable（5000））{
 System.out.println（ip +is reachable）; 
} 
 else {
 System.out.println（ip +is not reachable）; 
 
 
 
 $ b $ / code $ / pre 
 $ b $ p OUTPUT IS ：
 
 
 发送Ping请求到192.168.1.243 
 192.168.1.243不可达
  $ b pre 
 $ b 
这里是ping结果，当我ping从Windows 7内置Ping功能（CMD）
 
 
 
  
解决方案
使用
 <$ c $>  C> InetAddress.getByName（地址）.isReachable（超时）; 
  
 
I am tring to ping IP addresses from 192.168.1.1 to 192.168.1.254. First I was using I InetAddress class but it was bugged and some IPs where not reachable even if they are. After that I tried this method and it worked very well for single ping IP but when I put it inside for-loop all pinged IPs where reachable... Can you guys tell me what's wrong here?


CODE:
public class Main {
public static void main(String[] args) {
    String ip="192.168.1.";
    try
    {
        for(int i=0;i<=254;i++){
        String ip2=ip+i;
        boolean reachable = (java.lang.Runtime.getRuntime().exec("ping -n 1 "+ip2).waitFor()==0);
        if(reachable){
            System.out.println("IP is reachable:: "+ip2);
        }
        else{
            System.out.println("IP is not reachable: "+ip2);
        }
        }
    }catch(Exception e)
    {
        e.printStackTrace();
    }

}

}
EDIT 1:

I used built in Java function to preform pinging but it's not working (again)

here is code that I used
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
public class Test {

public static void main(String[] args) throws UnknownHostException, IOException {
    String ip = "192.168.1.243";
    InetAddress inet = InetAddress.getByName(ip);
    System.out.println("Sending Ping Request to " + ip);
    if (inet.isReachable(5000)){
        System.out.println(ip+" is reachable");
    }
    else{
        System.out.println(ip+" is not reachable");
    }

}
}
OUTPUT IS:
Sending Ping Request to 192.168.1.243
192.168.1.243 is not reachable
Also here is ping result when I do pinging from Windows 7 built in Ping function (cmd)

解决方案
Use isReachable() instead.
InetAddress.getByName(address).isReachable(timeout);


                        
这篇关于Ping函数返回所有ping过的IP地址是可达的的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！