Java android conver视频到bytearray

我试图用字节数组从sd卡传输视频。我写了代码，但我做错了什么。我的代码中有什么错误？我不知道我做错了什么 这是我的消息来源

public byte[] readBytes(Uri uri) throws IOException {

    InputStream inputStream = getContentResolver().openInputStream(uri);
    ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();


    int bufferSize = 1024;
    byte[] buffer = new byte[bufferSize];


    int len = 0;
    while ((len = inputStream.read(buffer)) != -1) {
        byteBuffer.write(buffer, 0, len);

    }


    return byteBuffer.toByteArray();
}



upload_btn.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            String fileName = "video.mp4";
            String completePath = Environment.getExternalStorageDirectory()
                    + "/" + fileName;

            File file = new File(completePath);
            Uri imageUri = Uri.fromFile(file);
            try {
                byte[] bytes = readBytes(imageUri);
                Log.e("Byte Array is", String.valueOf(bytes));
                Toast.makeText(getApplicationContext(),
                        String.valueOf(bytes), Toast.LENGTH_LONG).show();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    });

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我运行我的应用程序，结果是小字符串，而不是字节数组

String。的值从字节返回字符串。。。你想要字符串在哪里？没有。我用string.valueofs通过Terarry返回strean。那么这里有什么问题？