Question

当我运行我的应用程序并扫描IP时，由于某种原因它会冻结。此外，我不确定Yum方法在运行命令后是否退出，或者它是否永远存在。我的目标是制作像$ ./inLinuxRunMe &这样的东西，它在后台运行，当工作完成后，就会自行杀死。

我不认为我的Yum方法正在执行此操作，因为当我开始重载（例如播放视频等）时它会冻结。

public class MyShell
{
    public static String whatIsMyIP = null;

    public static void main(String args[])
    {
      t = new javax.swing.Timer(10000, new ActionListener() 
      {
        public void actionPerformed(ActionEvent ae) 
        {
        /* Scanner: if the ip change, show the new on too. */
        whatIsMyIP = MyShell.Yum("ifconfig eth0 | grep inet").toLowerCase());           
            /* Some logical conditions ... such as if ran then dont run, run once etc..*/ 
            bootMe();
         }
      });
      t.start();

      /* Launch: Main application server, runs forever as server */
      // MyShell.Yum("java -cp myjar.jar launch.MainApplicationAsServer");
    }

    /* Boot loader */
    public static void bootMe() throws IOException
    {
      MyShell.Yum("java -cp myjar.jar launch.MainApplicationAsServer");
    }

    /* Question: How to optimize it? So that, 
             it execute the shell command and quite*/
    public static String Yum(String cmds)
    {
        String value = "";
        try 
        {
          String cmd[] = {"/bin/sh", "-c", cmds };       
          Process p=Runtime.getRuntime().exec(cmd);       
          BufferedReader reader=new BufferedReader(
                                                                            new InputStreamReader(p.getInputStream())); 
          String line=reader.readLine(); 

          while(line!=null) 
          { 
            value += line ;
            line=reader.readLine(); 
          } 
          p.waitFor(); 

        } catch(IOException e1) {
        } catch(InterruptedException e2) { 
        }
        return value;
    }
}

Answer 1

在单独的线程中运行Yum()方法。

Answer 2

来自Java API：

Constructor Summary
Timer(int delay, ActionListener listener)
      Creates a Timer that will notify its listeners every `delay` milliseconds.

所以它每10秒重复一次。你需要告诉它不要重复：

public void setRepeats(boolean flag)

    If flag is false, instructs the Timer to send only one action event to its listeners.

    Parameters:
        flag - specify false to make the timer stop after sending its first action event

所以：

t = new javax.swing.Timer(10000, new ActionListener() {...});
t.setRepeats(false);
t.start();

使用简单的Runtime.getRuntime（）时执行代码冻结.exec（cmd）

2 个答案: