code: public static byte[] readBytes(ByteBuffer buffer, int start, int end) {
  		byte[] bs = new byte[end - start];
  		System.arraycopy(buffer.array(), start, bs, 0, bs.length);
  		return bs;
  	}
docs: 读取指定区间的数据
  
  @param buffer {@link ByteBuffer}
  @param start 开始位置
  @param end 结束位置
  @return bytes