User.mapper.xml
<?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.dxj.mapper.DeptMapper">
<resultMap id="DeptMap" type="Dept">
<id column="de_id" jdbcType="INTEGER" property="id" />
<result column="de_name" jdbcType="VARCHAR" property="name" />
<result column="de_loc" jdbcType="VARCHAR" property="loc" />
<result column="de_time" property="date" />
<result column="de_by" jdbcType="VARCHAR" property="person" />
</resultMap>
<!-- 增加 -->
<insert id="save">
INSERT INTO dept_tab(de_name,de_loc,de_time,de_by)
VALUES(#{name},#{loc},#{date},#{person})
</insert>
<!-- 全查询 -->
<select id="findAll" resultMap="DeptMap">
SELECT * FROM dept_tab
</select>
<!-- 修改-->
<update id="update">
UPDATE dept_tab
<set>
<if test="upd.name!=null">
de_name=#{upd.name}
</if>
<if test="upd.loc!=null">
de_loc=#{upd.loc}
</if>
<if test="upd.date!=null">
de_time=#{upd.date}
</if>
<if test="upd.person!=null">
de_by=#{upd.person}
</if>
</set>
WHERE de_id=#{upd.id}
</update>
<!-- 删除-->
<delete id="del">
DELETE FROM dept_tab WHERE de_id=#{id}
</delete>
</mapper>



#{}是预编译处理,会将sql中的#{}替换为?号,调用PreparedStatement的set方法来赋值,可以有效的防止SQL注入,提高系统安全性;
${}是字符串替换,把${}替换成变量的值;


原文:https://www.cnblogs.com/dxjx/p/12591013.html