####1、实现功能
用字节的 方式读取文件 并且将
其转换成String显示：

####2、功能实现

public void getContentFromFile() {

        final String FILE_NAME = "/data/test.txt";
        File file = new File(FILE_NAME);
        byte[] bufferFile =  null;
        ByteArrayOutputStream bos = new ByteArrayOutputStream((int) file.length());
        try {

            Log.v(TAG, "try  open /data/test.txt");

            FileInputStream fis = new FileInputStream(file);

            if (fis != null) {

                Log.v(TAG, "read /data/test.txt");
                byte[] bytes = new byte[(int) file.length()];

                int num = 0;
                while ((num = fis.read(bytes)) != -1) {

                    bos.write(bytes, 0, (int) file.length());
                    //将字节获得到字节数组
                    bufferFile = bos.toByteArray();

                    Log.v(TAG, "lum_1");
                    System.out.println(Arrays.toString(bufferFile));
                    
                    //将字节数组转换成字符串显示
                    String str = new String(bufferFile,"ascii");
                    System.out.println(str);


                }


            }
            fis.close();


        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }