android InputStream 转byte[]

  public static byte[] streamToBytes(InputStream input) {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        byte[] buffer = new byte[4096];
        int n = 0;
        try {
            while (-1 != (n = input.read(buffer))) {
                output.write(buffer, 0, n);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return output.toByteArray();
    }