可以用于检测某个ip地址是否可以ping通,网上找的,可以直接运行.

package com.demo;

import java.io.*;

public class ping
{
    public static void main(String [] args)
    {
        System.out.println(pingServer("localhost",100));
    }

    /**
    * ping the server
    * @param server String
    * @param timeout int
    * @return boolean
    * @throws IOException
    */
    public static boolean pingServer(String server,int timeout)
    {
      BufferedReader in = null;
      Runtime r = Runtime.getRuntime();  

      String pingCommand = "ping " + server + " -n 1 -w " + timeout;
      try
      {
          Process p = r.exec(pingCommand);
          if (p == null)
          {
            return false;
          }
          in = new BufferedReader(new
                 InputStreamReader(p.getInputStream()));
          String line = null;
          while ( (line = in.readLine()) != null)
          {
            if (line.startsWith("Reply from"))
            {
              return true;
            }
            System.out.println(line);
          }
          in.close();
      }
      catch (Exception ex)
      {
          ex.printStackTrace();
          return false;
      }
      return false;
    }  

};