mybatis---mapper.xml文件_mybatis maper.xml在线-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_40471291/article/details/84100802

本文详细解析了MyBatis映射文件的结构与使用方法，包括SQL语句的编写、参数类型处理及结果映射，适用于初学者和进阶开发者理解MyBatis的工作原理。

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "mybatis-3-mapper.dtd" >
<mapper namespace="com.it.mybaties.mapper.UserMapper">
  <select id="getUserById" resultType="com.it.mybaties.pojo.User" parameterType="Integer">
  	select * from user where id=#{id}
  </select>
  
  <select id="getUserByUsername" parameterType="String" resultType="com.it.mybaties.pojo.User">
  	<!-- 用$符号时,只能用value 其他都是错 -->
  	<!-- select * from user where username like '%${value}%' -->
  	<!-- #号里随便写什么 -->
  	select * from user where username like "%"#{username}"%"
  </select>
  
  <insert id="insertUser" parameterType="com.it.mybaties.pojo.User">
  	<selectKey keyProperty="id" resultType="Integer" order="AFTER">
  		select LAST_INSERT_ID()
  	</selectKey>
  	insert into user (username,sex,birthday,address) values (#{username},#{sex},#{birthday},#{address})
  </insert>
  
  <update id="updateUser" parameterType="com.it.mybaties.pojo.User">
  	update user set username=#{username},sex=#{sex},birthday=#{birthday},address=#{address}  where id=#{id}
  </update>
  
  <delete id="deleteUser" parameterType="Integer">
  	delete from user where id=#{id}
  </delete>
  
  
</mapper>