/**
 * 解析从数据库获取的二进制data数据
 *
 * @param messageEntity
 */
private void readMessageContentFromDB(MessageEntity messageEntity, MessageVO messageVO) {
    try {
        //从数据库t_messages_x表中读取到消息内容字段_data的二进制数据为
        byte[] data = messageEntity.getData();
        //1. 先把二进制数据转化为协议栈消息内容。
        WFCMessage.MessageContent protoContent = null;
        protoContent = WFCMessage.MessageContent.parseFrom(data);
        //2. 调用MessageContentFactory接口解析为消息内容。
        MessageContent messageContent = MessageContentFactory.decodeMessageContent(protoContent);
        //3. 检查是哪种消息，如果没有定义，会回落到UnknownMessageContent。自定义消息看本函数最后的注释。
        if (messageContent instanceof TextMessageContent) {
            // 文本消息
            TextMessageContent txt = (TextMessageContent) messageContent;
            messageVO.setType(1);
            messageVO.setText(txt.getText());
        } else if (messageContent instanceof ImageMessageContent) {
            // 图片消息
            ImageMessageContent img = (ImageMessageContent) messageContent;
            messageVO.setType(3);
            messageVO.setRemoteMediaUrl(img.getRemoteMediaUrl());
        } else if (messageContent instanceof FileMessageContent) {
            // 附件消息
            FileMessageContent file = (FileMessageContent) messageContent;
            messageVO.setFileName(file.getName());
            messageVO.setFileSize(file.getSize());
            messageVO.setType(5);
            messageVO.setRemoteMediaUrl(file.getRemoteMediaUrl());
        } else if (messageContent instanceof VideoMessageContent) {
            // 视频消息
            VideoMessageContent video = (VideoMessageContent) messageContent;
            messageVO.setType(6);
            messageVO.setRemoteMediaUrl(video.getRemoteMediaUrl());
        }
    } catch (Exception e) {
        LOG.error("An error occurred:", e);
    }
}