Mybatis——动态sql+字符串匹配导致的判断问题 [数据库教程]

  • Z时代
  • 2024-01-10
  • 分类：综合

database

在mybatis的学习中,狂神建议字符串匹配直接将模糊匹配的符号放在字符串中,如:匹配‘keWord‘,那么实际所使用的参数应该为‘%keyWord%‘

map.put("keyWord","%" + keyWord + "%");

<select id="getUserLikeGaojianList" parameterType="map" resultMap="userLikeGaojianEntity">
    SELECT *
    FROM news_base_gaojian g LEFT JOIN news_base_gaojian_like l ON l.gid=g.gj_id and l.uid = #{uId} and type=2
    <where>
        is_delete = 0 AND gj_user_type = #{userType} AND gj_hash_p = #{gjHashP}
        <if test="tougaoState != null">
            AND gj_tougao_pingtai_num >= #{tougaoState}
        </if>
        <if test="gjType != null">
            AND gj_type = #{gjType}
        </if>
        <if test="keyWord != null ">
            AND ( gj_title LIKE #{keyWord} OR gj_title2 LIKE #{keyWord} OR gj_bianji LIKE #{keyWord} OR gj_laiyuan LIKE #{keyWord} OR gj_excerpt LIKE #{keyWord})
        </if>
        <if test="date1 != null and date2 != null">
            AND gj_lasttime &lt;= #{date1} AND  &gt;= #{date2}
        </if>
    </where>
    LIMIT 0,20
</select>

注意:此时就不能用keyWord != null做为动态sql中test的参数,因为当关键字keyWord为空时,keyWord="%null%"

解决方案:

  1. 修改.xml文件

        <select id="getUserLikeGaojianList" parameterType="map" resultMap="userLikeGaojianEntity">
            SELECT *
            FROM news_base_gaojian g LEFT JOIN news_base_gaojian_like l ON l.gid=g.gj_id and l.uid = #{uId} and type=2
            <where>
                is_delete = 0 AND gj_user_type = #{userType} AND gj_hash_p = #{gjHashP}
                <if test="tougaoState != null">
                    AND gj_tougao_pingtai_num >= #{tougaoState}
                </if>
                <if test="gjType != null">
                    AND gj_type = #{gjType}
                </if>
                <if test="keyWord != ‘%null%‘ ">
                    AND ( gj_title LIKE #{keyWord} OR gj_title2 LIKE #{keyWord} OR gj_bianji LIKE #{keyWord} OR gj_laiyuan LIKE #{keyWord} OR gj_excerpt LIKE #{keyWord})
                </if>
                <if test="date1 != null and date2 != null">
                    AND gj_lasttime &lt;= #{date1} AND  &gt;= #{date2}
                </if>
            </where>
            LIMIT 0,20
        </select>

  2. 修改service层

    <if test="keyWord != null ">
        AND ( gj_title LIKE #{keyWord} OR gj_title2 LIKE #{keyWord} OR gj_bianji LIKE #{keyWord} OR gj_laiyuan LIKE #{keyWord} OR gj_excerpt LIKE #{keyWord})
        </if>

Mybatis——动态sql+字符串匹配导致的判断问题

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