java-执行终端命令

try {
				
  Process p = Runtime.getRuntime().exec("ls -a"); 
 InputStreamReader ir = new InputStreamReader(p.getInputStream());    
 LineNumberReader input = new LineNumberReader (ir);      //创建IO管道，准备输出命令执行后的显示内容  
String line;    
 while ((line = input.readLine ()) != null){     //按行打印输出内容  
 System.out.println(line);    }

} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}