Android 把文件转换成字符流

 /**
     * 这个是把文件变成二进制流
     *
     * @param imagepath
     * @return
     * @throws Exception
     */
    public static byte[] readStream(String imagepath) throws Exception {
        FileInputStream fs = new FileInputStream(imagepath);
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while (-1 != (len = fs.read(buffer))) {
            outStream.write(buffer, 0, len);
        }
        outStream.close();
        fs.close();
        return outStream.toByteArray();
    }