mybatis 批量更新

Posted 2020-10-30 aLa神灯

https://blog.csdn.net/xu1916659422/article/details/77971696

 

注意第一种方法要想成功，需要在db链接url后面带一个参数  &allowMultiQueries=true

即：  jdbc:mysql://localhost:3306/mysqlTest?characterEncoding=utf-8&allowMultiQueries=true

    <!-- 这次用resultmap接收输出结果  -->
    <select id="findByName" parameterType="string" resultMap="customerMap">
        select * from t_customer where c_name like concat(‘%‘, #{name},‘%‘) order by c_ceroNo limit 0,100
    </select>


    <!-- 批量更新第一种方法，通过接收传进来的参数list进行循环着组装sql -->
    <update id="batchUpdate" parameterType="java.util.Map">
        <!-- 接收list参数，循环着组装sql语句，注意for循环的写法
             separator=";" 代表着每次循环完，在sql后面放一个分号
             item="cus" 循环List的每条的结果集
             collection="list" list 即为 map传过来的参数key -->
        <foreach collection="list" separator=";" item="cus">
            update t_customer set
            c_name = #{cus.name},
            c_age = #{cus.age},
            c_sex = #{cus.sex},
            c_ceroNo = #{cus.ceroNo},
            c_ceroType = #{cus.ceroType}
            where id = #{cus.id}
        </foreach>
    </update>

    <!-- 批量更新第二种方法，通过 case when语句变相的进行批量更新 -->
    <update id="batchUpdateCaseWhen" parameterType="java.util.Map">
        update t_customer
        <trim prefix="set" suffixOverrides=",">
            <!-- 拼接case when 这是一种写法 -->
            <!--<foreach collection="list" separator="" item="cus" open="c_age = case id" close="end, ">-->
            <!--when #{cus.id} then #{cus.age}-->
            <!--</foreach>-->

            <!-- 拼接case when 这是另一种写法，这种写着更专业的感觉 -->
            <trim prefix="c_name =case" suffix="end,">
                <foreach collection="list" item="cus">
                    <if test="cus.name!=null">
                        when id=#{cus.id} then #{cus.name}
                    </if>
                </foreach>
            </trim>
            <trim prefix="c_age =case" suffix="end,">
                <foreach collection="list" item="cus">
                    <if test="cus.age!=null">
                        when id=#{cus.id} then #{cus.age}
                    </if>
                </foreach>
            </trim>
            <trim prefix="c_sex =case" suffix="end,">
                <foreach collection="list" item="cus">
                    <if test="cus.sex!=null">
                        when id=#{cus.id} then #{cus.sex}
                    </if>
                </foreach>
            </trim>
            <trim prefix="c_ceroNo =case" suffix="end,">
                <foreach collection="list" item="cus">
                    <if test="cus.ceroNo!=null">
                        when id=#{cus.id} then #{cus.ceroNo}
                    </if>
                </foreach>
            </trim>
            <trim prefix="c_ceroType =case" suffix="end,">
                <foreach collection="list" item="cus">
                    <if test="cus.ceroType!=null">
                        when id=#{cus.id} then #{cus.ceroType}
                    </if>
                </foreach>
            </trim>
        </trim>
        <where>
            <foreach collection="list" separator="or" item="cus">
                id = #{cus.id}
            </foreach>
        </where>
    </update>