java在linux下ping功能实现
import java.io.*;
public class Ping
{
    public static void main(String [] args)
    {
        System.out.println(pingServer("www.baidu.com"));
    }

    /**
    * ping the server
    * @param server String
    * @param timeout int
    * @return boolean
    * @throws IOException
    */
    public static boolean pingServer(String server)
    {
      BufferedReader in = null;
      Runtime r = Runtime.getRuntime(); 
      boolean iFlag = false;
      String pingCommand = "ping "+"-c2 " + server ;
      System.out.println(pingCommand);
      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.contains("64 bytes from"))
            {
            iFlag=true;
            }
            System.out.println(line);
          }
          in.close();
      }
      catch (Exception ex)
      {
          ex.printStackTrace();
          return false;
      }
      return iFlag;
    } 

};