文件转换成byte数组

    /**
     * 文件 File file = new File("...");
     * @param filePath
     * @return
     */
    public static byte[] File2byte(File filePath) {
        byte[] buffer = null;
        try {
            FileInputStream fis = new FileInputStream(filePath);
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            byte[] b = new byte[1024];
            int n;
            while ((n = fis.read(b)) != -1) {
                bos.write(b, 0, n);
            }
            fis.close();
            bos.close();
            buffer = bos.toByteArray();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return buffer;
    }

byte数组上传到文件

    /**
     * @param bytes byte数组
     * @param fileRoute 文件路径
     * @param fileName 文件名
     */
    public static void upload(byte[] bytes,String fileRoute,String fileName) {
        try {
            File directory=new File(fileRoute);
            if (!directory.exists()){
                directory.mkdirs();
            }
            File file = new File(directory, fileName);
            BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
            bos.write(bytes);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }