Re: [suse-programming-e] how to call linux command with java ?

16 Apr 2003

      Linux Aremania wrote :

| I wanna make java application which call linux
| command, but I don't know how to call linux command.
| For example : I wanna display the output of "ps -ax"
| command in applet.
|

you can't do that from an applet, protected !!, what you can do is write a 
java program that does this. But your browser won't allow you to execute 
external commands from an applet

in a java program, this class can help you :

//
//  (C) Dries Pruimboom (dries@irssystems.nl)
//  Use at own risk !!
//  Might not be fit for your use, you decide !!
//
//
// Executer class for simple execution of external programs
//
//  General usage :
//
//    Executer exe = new Executer("find /");
//    String line;
// 
//    while ((line = exe.ReadLine())!=null)
//    {
//        System.out.println(line);
//    }
//
class Executer
{
    Process proc;
    BufferedReader input;
    BufferedWriter output;
    public int ExitVal;

    //
    //  str contains the command to execute
    //
    Executer(String str)
    {
      try 
      {
         Runtime runtime = Runtime.getRuntime();
         proc = runtime.exec(str);

         input = new BufferedReader(new 
InputStreamReader(proc.getInputStream()));
         output = new BufferedWriter(new 
OutputStreamWriter(proc.getOutputStream()));
      } 
      catch (Exception e)
      {
         System.out.println(e);
      }
    }

    //
    // Read a line of output from external program
    //
    public String ReadLine()
    {
       String hlp=null;
       try {
          hlp = input.readLine();
       }
       catch (Exception e)
       {
          hlp=null;
       }
       return (hlp);
    }

    //
    //  Write line of data to external program
    //
    public void WriteLine(String str)
    {
       try 
       {
         output.write(str);
         output.flush();
       }
       catch (Exception e)
       {
       }
    }

    public boolean DataAvail()
    {
        boolean res=false;
        try
        {
           res = input.ready();
        }
        catch (IOException e)
        {
        }

        return(res);
    }

    //
    //  Do a more or less nice end of this process
    //  this is not actually needed!.
    //
    public void EndProcess()
    {
        try {
          input.close();
          output.close();
        }
        catch (Exception e)
        {
        }
    }

    public boolean Stopped()
    {
       boolean res = false; 

       if (!DataAvail())
       {
          try {
             ExitVal = proc.exitValue();
             res=true;
          }
          catch (IllegalThreadStateException e)
          {
          }
       }
       return(res);
    }

}

Hope this will help you

Grtz Dries

-- 
<End of message>