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用别名来简化工具类

用别名来简化工具类

其实别名这个技术挺鸡肋的，如果你使用了别名，Idea的代码跳转就无法实现。但是如果为一些常用的工具类设置别名，可以让mapper.xml文件看上去更优雅一点。

我们项目保留了一份MyBatis的配置文件，所以正好可以用来配置工具类的别名：

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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <settings>
        <setting name="cacheEnabled" value="true"/>  <!-- 全局映射器启用缓存 -->
        <setting name="useGeneratedKeys" value="true"/>  <!-- 允许 JDBC 支持自动生成主键 -->
        <setting name="defaultExecutorType" value="REUSE"/> <!-- 配置默认的执行器 -->
        <setting name="logImpl" value="SLF4J"/> <!-- 指定 MyBatis 所用日志的具体实现 -->
        <!-- <setting name="mapUnderscoreToCamelCase" value="true"/>  驼峰式命名 -->
    </settings>

    <typeAliases>
        <typeAlias type="org.apache.commons.collections4.CollectionUtils" alias="CollectionUtils"/>
        <typeAlias type="org.apache.commons.lang3.StringUtils" alias="StringUtils"/>
    </typeAliases>

</configuration>

在Mapper中的用法如下：

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<mapper namespace="com.sdstc.tmp.server.mapper.TrendModelMapper">


    <select id="selectForUpdateById" resultType="com.sdstc.tmp.server.entity.TrendModel">
        select id, favorites_count, browse_count
        from t_trend_model
        where is_delete = '0'
          and id = #{id} for update
    </select>

    <select id="pageTrendModel" resultType="com.sdstc.tmp.server.entity.TrendModel">
        select * from t_trend_model trm

        <!-- 登录状态，且搜索条件中包含收藏 -->
        <if test="loginFlag == 1 and condition.collect == 1">
            join t_favorite tf on trm.id = tf.trend_model_id
        </if>

        <!-- 登录状态，且搜索条件中包含浏览 -->
        <if test="loginFlag == 1 and condition.viewed == 1">
            join t_viewed tv on trm.id = tv.trend_model_id
        </if>
        where trm.is_delete = 0

        <!-- 登录状态，且搜索条件中包含收藏 -->
        <if test="loginFlag == 1 and condition.collect == 1">
            and tf.is_delete = 0
            and tf.creator = #{userId}
        </if>

        <!-- 登录状态，且搜索条件中包含浏览 -->
        <if test="loginFlag == 1 and condition.viewed == 1">
            and tv.is_delete = 0
            and tv.creator = #{userId}
            and tv.org_id = #{tenantId}
        </if>

        <!-- 关键字 -->
        <if test="@StringUtils@isNotBlank(condition.keyword)">
            <bind name="keyword" value="'%' + condition.keyword + '%'"/>
            and (trm.theme like #{keyword} or trm.design_points like #{keyword})
        </if>

        <!-- 趋势主题（in查询） -->
        <if test="@CollectionUtils@isNotEmpty(condition.themes)">
            AND trm.theme in
            <foreach collection="condition.themes" open="(" close=")" item="themes" separator=",">
                #{theme}
            </foreach>
        </if>

        <!-- 趋势主题（like查询） -->
        <if test="@StringUtils@isNotBlank(condition.theme)">
            <bind name="theme" value="'%' + condition.theme + '%'"/>
            AND trm.theme like #{theme}
        </if>

        <!-- 适用品牌 -->
        <if test="@CollectionUtils@isNotEmpty(condition.brands)">
            AND trm.brand in
            <foreach collection="condition.brands" open="(" close=")" item="brand" separator=",">
                #{brand}
            </foreach>
        </if>

        <!-- 允许预览，个人身份登录 -->
        <if test="loginFlag == 1 and condition.allowView == 1 and personalLogin">
            AND (trm.personal_allow_view = 1 or trm.personal_allow_used = 1)
        </if>
        <!-- 允许预览，企业身份登录 -->
        <if test="loginFlag == 1 and condition.allowView == 1 and !personalLogin">
            AND (trm.company_allow_view::jsonb ??| array[#{tenantId}] or trm.company_allow_used::jsonb ??| array[#{tenantId}])
        </if>

        <!-- 发布状态 -->
        <if test="@CollectionUtils@isNotEmpty(condition.publishStatus)">
            AND trm.publish_status in
            <foreach collection="condition.publishStatus" open="(" close=")" item="publishStatusItem" separator=",">
                #{publishStatusItem}
            </foreach>
        </if>

        <!-- 型体号（in查询） -->
        <if test="@CollectionUtils@isNotEmpty(condition.modelNumbers)">
            AND trm.model_number in
            <foreach collection="condition.modelNumbers" open="(" close=")" item="modelNumber" separator=",">
                #{modelNumber}
            </foreach>
        </if>

        <!-- 型体号（like查询） -->
        <if test="@StringUtils@isNotBlank(condition.modelNumber)">
            <bind name="modelNumber" value="'%' + condition.modelNumber + '%'"/>
            AND trm.model_number like #{modelNumber}
        </if>

        <!-- 鞋底 -->
        <if test="@CollectionUtils@isNotEmpty(condition.soles)">
            AND trm.sole in
            <foreach collection="condition.soles" open="(" close=")" item="sole" separator=",">
                #{sole}
            </foreach>
        </if>

        <!-- 跟型 -->
        <if test="@CollectionUtils@isNotEmpty(condition.heelTypes)">
            AND trm.heel_type in
            <foreach collection="condition.heelTypes" open="(" close=")" item="heelType" separator=",">
                #{heelType}
            </foreach>
        </if>

        <!-- 跟高 -->
        <if test="@CollectionUtils@isNotEmpty(condition.heelHeights)">
            AND trm.heel_height in
            <foreach collection="condition.heelHeights" open="(" close=")" item="heelHeight" separator=",">
                #{heelHeight}
            </foreach>
        </if>

        <!-- 款式类型 -->
        <if test="@CollectionUtils@isNotEmpty(condition.shapeTypes)">
            AND trm.shape_type in
            <foreach collection="condition.shapeTypes" open="(" close=")" item="shapeType" separator=",">
                #{shapeType}
            </foreach>
        </if>

        <!-- 流行趋势 -->
        <if test="@CollectionUtils@isNotEmpty(condition.trendTags)">
            AND trm.trend_tags::jsonb ??|
            <foreach collection="condition.trendTags" open="array[" close="]" item="trendTag" separator=",">
                #{trendTag}
            </foreach>
        </if>

        <!-- 流行地区 -->
        <if test="@CollectionUtils@isNotEmpty(condition.regions)">
            AND trm.regions::jsonb ??|
            <foreach collection="condition.regions" open="array[" close="]" item="region" separator=",">
                #{region}
            </foreach>
        </if>

        <!-- 场景风格 -->
        <if test="@CollectionUtils@isNotEmpty(condition.styles)">
            AND trm.styles::jsonb ??|
            <foreach collection="condition.styles" open="array[" close="]" item="style" separator=",">
                #{style}
            </foreach>
        </if>

        <!-- 面料元素 -->
        <if test="@CollectionUtils@isNotEmpty(condition.materialElements)">
            AND trm.material_elements::jsonb ??|
            <foreach collection="condition.materialElements" open="array[" close="]" item="materialElement"
                     separator=",">
                #{materialElement}
            </foreach>
        </if>

        <!-- 装饰元素 -->
        <if test="@CollectionUtils@isNotEmpty(condition.decorativeElements)">
            AND trm.decorative_elements::jsonb ??|
            <foreach collection="condition.decorativeElements" open="array[" close="]" item="decorativeElement"
                     separator=",">
                #{decorativeElement}
            </foreach>
        </if>

        <!-- 工艺 -->
        <if test="@CollectionUtils@isNotEmpty(condition.crafts)">
            AND trm.crafts::jsonb ??|
            <foreach collection="condition.crafts" open="array[" close="]" item="craft"
                     separator=",">
                #{craft}
            </foreach>
        </if>

        <!-- 适用季节 -->
        <if test="@CollectionUtils@isNotEmpty(condition.seasons)">
            AND trm.seasons::jsonb ??|
            <foreach collection="condition.seasons" open="array[" close="]" item="season"
                     separator=",">
                #{season}
            </foreach>
        </if>

        <!-- 色系 -->
        <if test="@CollectionUtils@isNotEmpty(condition.colors)">
            AND trm.colors::jsonb ??|
            <foreach collection="condition.colors" open="array[" close="]" item="color"
                     separator=",">
                #{color}
            </foreach>
        </if>

        <!-- 是否推荐 -->
        <if test="condition.isRecommend != null">
            AND trm.is_recommend = #{condition.isRecommend}
        </if>

        <!-- 设计师Id -->
        <if test="@StringUtils@isNotBlank(condition.designerId)">
            AND trm.designer_id = #{condition.designerId}
        </if>

        <if test="@CollectionUtils@isNotEmpty(orderItems)">
            order by
            <foreach collection="orderItems" item="orderItem"
                     separator=",">
                ${orderItem.column} <if test="not orderItem.asc">desc</if>
            </foreach>
        </if>
    </select>
</mapper>