Mybatis的一些使用总结（持续更新。。。。）

基础

通过 映射数据库与实体类的字段。

<!-- 映射对应的Mapper接口  -->
<mapper namespace="com.xxx.xx.mapper.xxxMapper">
 <!-- 通用查询映射结果 -->
    <resultMap id="ResultMap" type="com.ydmh.api.entity.BusinessBaseEntity">
        <result column="DM" property="fwsdm"/>
        <result column="MC" property="fwsmc"/>
        <result column="FR" property="fddbr"/>
        <result column="ZRSJ" property="zrsj"/>
        <result column="sfsc" property="sfsc"/>
        <result column="dzs" property="dzs"/>
        <result column="FY" property="sywlf"/>
        <result column="sfdz" property="sfdz"/>
        <result column="PJMC" property="pjmc"/>
        <result column="GZSJ" property="gzsj"/>
        <result column="DZSJ" property="dzsj"/>
        <result column="LLSJ" property="llsj"/>
        <result column="LXMC" property="lxmc"/>
        <result column="LOGO" property="logo"/>
        <result column="YHID" property="yhid"/>


    </resultMap>

Where标签

和 if test 标签还是有区别的，只匹配单个成立之后结束匹配，比如，下面的查询当 selectType = 0 的时候就执行 where DATE_FORMAT(t5.YF,’%Y%m’) = DATE_FORMAT(CURDATE(),’%Y%m’),后面的不再进行判断。

 <where>
            <choose>
                <when test="selectType == 0">
                    DATE_FORMAT(t5.YF,'%Y%m') = DATE_FORMAT(CURDATE(),'%Y%m')
                </when>
                <when test="selectType == 1">
                    PERIOD_DIFF( date_format( now( ), '%Y%m' ), date_format( t5.YF, '%Y%m' ) ) = 1
                </when>
                <when test="selectType == 2">
                    QUARTER(t5.YF) = QUARTER(NOW())
                </when>
                <when test="selectType == 3">
                    QUARTER(t5.YF) = QUARTER(DATE_SUB(NOW(),INTERVAL 1 QUARTER))
                </when>
                <when test="selectType == 4">
                    YEAR(t5.YF)=YEAR(NOW())
                </when>
                <when test="selectType == 5">
                    YEAR(t5.YF) = YEAR(DATE_SUB(NOW(),INTERVAL 1 YEAR))
                </when>
                <when test="selectType == 6">
                    date_format(t5.YF,'%Y-%m-%d') between #{startTime} AND #{endTime}
                </when>

            </choose>
        </where>

if标签

如果，就。。。

  <if test="lxmc !='不限' and lxmc !=null and lxmc !=''">
            where t14.LXMC = #{lxmc}
        </if>

foreach 标签的使用

可以在Mapper层通过@Param(“xxx”)指定一个List的别名。

Boolean updateStatusByMeterIds(@Param("meterIds") List<Long> meterIds);

<update id="updateStatusByMeterIds">
        update test_table set STATUS = '2'
        <if test="meterIds!=null and meterIds.size>0">
            WHERE test_id IN
            <foreach collection="meterIds" item="ids" index="index" open="(" close=")" separator=",">
                #{ids}
            </foreach>
        </if>
    </update>