feat:

1.消息撤回功能
2.管理员拉黑功能
3.管理员撤回消息功能
4.消息类型可扩展

mallchat-common/src/main/resources/mapper/user/BlackMapper.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
+<mapper namespace="com.abin.mallchat.common.user.mapper.BlackMapper">
+
+</mapper>