android 读取txt文件

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        String fileName = "/sdcard/y.txt";//文件路径
        // 也可以用String fileName = "mnt/sdcard/Y.txt";
        String res = "";
        try {
            FileInputStream fin = new FileInputStream(fileName);
            // FileInputStream fin = openFileInput(fileName);
            // 用这个就不行了，必须用FileInputStream
            int length = fin.available();
            byte[] buffer = new byte[length];
            fin.read(buffer);
            res = EncodingUtils.getString(buffer, "UTF-8");////依Y.txt的编码类型选择合适的编码，如果不调整会乱码
            fin.close();//关闭资源
            System.out.println("res--->"+res);
            int a=Integer.parseInt(res.substring(3, 5));
            int b=Integer.parseInt(res.substring(8, 10));
            System.out.println(a+"res--->"+b);//获取的a.b
        } catch (Exception e) {
            e.printStackTrace();
        }
    }