图解Mybatis配置文件

Posted 2021-03-03 Jaine

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>

View Code

 

 #{}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;