apk(java)应用程序调用系统命令

private void LsInfo()
    {
		
    	try {
    		//String[] cmd = new String[]{"sh","-c","ls -l"};
    		String[] cmd = new String[]{"sh","-c","ls -l"};
    		Process ps = Runtime.getRuntime().exec(cmd);
//////////////////////////////第一种，以   byte[] buf方式将logcat 出来的信息保存在/data/data/com.logcat.logcat目录下 lsll.txt====================	
    		
//        	FileOutputStream fileOutputStream = null;
//        	File file = new File("/data/data/com.logcat.logcat", "lsll.txt");
//        	fileOutputStream = new FileOutputStream(file);
//    		InputStream is = ps.getInputStream();
//    		int ch=0;
//    		byte[] buf = new byte[1024];
//    		do {
//				ch = is.read(buf);
////				Log.v("===========logcat=======", "=====================buf===============start"+ buf);
//				if (ch <= 0)
//					break;
//				fileOutputStream.write(buf, 0, ch);
//
//			} while (true);
//			is.close();
//			fileOutputStream.close();
////////////////////////第一种end	
/////////////////////////////第二种，直接返回	其结果字符串给应用使用		
			BufferedReader br = new BufferedReader(new InputStreamReader(ps.getInputStream()));
    		StringBuffer sb = new StringBuffer();
    		String line;
    		while ((line = br.readLine()) != null) {
    		sb.append(line).append("\n");
    		}
    		String result = sb.toString();
    		System.out.println(result);
////////////////////////第二种end
    		} catch (Exception e) {
    		e.printStackTrace();
    		}
    }