Mybatis高階-resultMap之collection聚集
摘要：
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版權宣告：本文由 低調小熊貓 發表於 低調小熊貓的部落格
轉載宣告：自由轉載-非商用-非衍生-保持署名，非商業轉載請註明作者及出處，商業轉載請聯絡作者本人qq:2696284032
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簡介
聚集元素用來處理“一對多”的關係。需要指定對映的Java實體類的屬性，屬性的javaType（一般為ArrayList）；列表中物件的型別ofType（Java實體類）；對應的資料庫表的列名稱；
額，估計這樣說大家聽不懂，簡單的意思就是把兩張表聯絡起來，用於解決一些奇怪的需求
程式碼
1.定義簡單的sql片段
<!-- 基本查詢--> <sql id="vo_select"> SELECT vo.expenseId, vo.projectId, vo.expenseUserId, sua.realName as expenseUserName, vo.expenseTime, vo.expenseTypeId, vo.beneficialDepartmentId, sd.name as beneficialDepartmentName, vo.currencyId, vo.money, vo.paperCheckerId, vo.paperCheckerTime, vo.paidDepartmentId, vo.paidUserId, vo.paidTime, vo.expenseNote, vo.description, vo.currentStatus, vo.invoiceAmount, vo.paperFlag, vo.recordFlag, vo.createUserId, vo.createTime FROM p_expense vo INNER JOIN sys_user_archive sua ON sua.userId=vo.expenseUserId INNER JOIN sys_department sd ON sd.departmentId=vo.beneficialDepartmentId </sql>
2.查詢條件拼接，返回resultMap
<select id="findAll" parameterType="Pasv" resultMap="pexpenseMap">
<include refid="vo_select"/>
WHERE 1=1
<!--根據登陸人判斷流程稽核步驟的人是否一樣 -->
<if test="vo.userId !=null and vo.userId !=''">
AND
(
EXISTS(
select 0 from p_expense_flow pef
where pef.flag=0 and pef.checkUserIds like concat('%#',#{vo.userId},'#%')
AND pef.expenseID=vo.expenseId
)
)
</if>
<!-- 根據時間查詢 -->
<if test="vo.searchStartTime !=null and vo.searchStartTime !=''">
AND vo.createTime >=DATE_FORMAT(#{vo.searchStartTime},'%Y-%m-%d')
</if>
<if test="vo.searchEndTime !=null and vo.searchEndTime !=''">
AND vo.createTime <DATE_FORMAT(date_add(#{vo.searchEndTime}, INTERVAL 1 day),'%Y-%m-%d')
</if>
<!-- 註釋掉是避免從我的任務中查詢顯示一條資料-->
<!-- <if test="null!=vo.expenseId and ''!=vo.expenseId">
AND vo.expenseId = #{vo.expenseId}
</if> -->
<if test="null!=vo.projectId and ''!=vo.projectId">
AND vo.projectId = #{vo.projectId}
</if>
<if test="null!=vo.expenseUserId and ''!=vo.expenseUserId">
AND vo.expenseUserId = #{vo.expenseUserId}
</if>
<if test="null!=vo.expenseTime and ''!=vo.expenseTime">
AND vo.expenseTime = #{vo.expenseTime}
</if>
<if test="null!=vo.expenseTypeId and ''!=vo.expenseTypeId">
AND vo.expenseTypeId = #{vo.expenseTypeId}
</if>
<if test="null!=vo.beneficialDepartmentId and ''!=vo.beneficialDepartmentId">
AND vo.beneficialDepartmentId = #{vo.beneficialDepartmentId}
</if>
<if test="null!=vo.currencyId and ''!=vo.currencyId">
AND vo.currencyId = #{vo.currencyId}
</if>
<if test="null!=vo.money and ''!=vo.money">
AND vo.money = #{vo.money}
</if>
<!-- 根據報銷人 -->
<if test="vo.searchName !=null and vo.searchName !=''">
AND sua.realName LIKE CONCAT(CONCAT('%', #{vo.searchName}),'%')
</if>
<if test="null!=vo.paperCheckerId and ''!=vo.paperCheckerId">
AND vo.paperCheckerId = #{vo.paperCheckerId}
</if>
<if test="null!=vo.paperCheckerTime and ''!=vo.paperCheckerTime">
AND vo.paperCheckerTime = #{vo.paperCheckerTime}
</if>
<if test="null!=vo.paidDepartmentId and ''!=vo.paidDepartmentId">
AND vo.paidDepartmentId = #{vo.paidDepartmentId}
</if>
<if test="null!=vo.paidUserId and ''!=vo.paidUserId">
AND vo.paidUserId = #{vo.paidUserId}
</if>
<if test="null!=vo.paidTime and ''!=vo.paidTime">
AND vo.paidTime = #{vo.paidTime}
</if>
<if test="null!=vo.description and ''!=vo.description">
AND vo.description = #{vo.description}
</if>
<if test="null!=vo.currentStatus and ''!=vo.currentStatus">
AND vo.currentStatus = #{vo.currentStatus}
</if>
<if test="null!=vo.invoiceAmount and ''!=vo.invoiceAmount">
AND vo.invoiceAmount = #{vo.invoiceAmount}
</if>
<if test="null!=vo.paperFlag and ''!=vo.paperFlag">
AND vo.paperFlag = #{vo.paperFlag}
</if>
<if test="null!=vo.recordFlag and ''!=vo.recordFlag">
AND vo.recordFlag = #{vo.recordFlag}
</if>
<if test="null!=vo.createUserId and ''!=vo.createUserId">
AND vo.createUserId = #{vo.createUserId}
</if>
<if test="null!=vo.createTime and ''!=vo.createTime">
AND vo.createTime = #{vo.createTime}
</if>
<if test="null!=vo.enabled and ''!=vo.enabled">
AND vo.enabled = #{vo.enabled}
</if>
<!-- 根據報銷金額範圍查詢 -->
<if test="vo.searchStartMoney !=null and vo.searchStartMoney !='' and vo.searchStartMoney!=0">
and vo.money <![CDATA[ >= ]]> #{vo.searchStartMoney}
</if>
<if test="vo.searchEndMoney !=null and vo.searchEndMoney !='' and vo.searchEndMoney!=0">
and vo.money <![CDATA[ <= ]]> #{vo.searchEndMoney}
</if>
</select>
3.定義resultMap，用於上面返回的resultMap，重點在於collection，先看程式碼，我下面解釋
<resultMap type="com.account.web.vo.project.PExpenseVo" id="pexpenseMap">
<id column="expenseId" property="expenseId"/>
<result column="projectId" property="projectId"/>
<result column="expenseUserId" property="expenseUserId"/>
<result column="expenseUserName" property="expenseUserName"/>
<result column="expenseTime" property="expenseTime"/>
<result column="expenseTypeId" property="expenseTypeId"/>
<result column="beneficialDepartmentId" property="beneficialDepartmentId"/>
<result column="beneficialDepartmentName" property="beneficialDepartmentName"/>
<result column="currencyId" property="currencyId"/>
<result column="money" property="money"/>
<result column="paperCheckerId" property="paperCheckerId"/>
<result column="paperCheckerTime" property="paperCheckerTime"/>
<result column="paidDepartmentId" property="paidDepartmentId"/>
<result column="paidUserId" property="paidUserId"/>
<result column="paidTime" property="paidTime"/>
<result column="expenseNote" property="expenseNote"/>
<result column="description" property="description"/>
<result column="currentStatus" property="currentStatus"/>
<result column="invoiceAmount" property="invoiceAmount"/>
<result column="paperFlag" property="paperFlag"/>
<result column="recordFlag" property="recordFlag"/>
<result column="createUserId" property="createUserId"/>
<result column="createTime" property="createTime"/>
<collection property="checkers"ofType="com.account.web.vo.admin.system.SysUserArchiveVo"
select="findChecker3" column="{expenseId2=expenseId}">
</collection>
</resultMap>
4.定義collection用的sql片段
<select id="findChecker3" resultType="com.account.web.vo.admin.system.SysUserArchiveVo">
select pef.expenseFlowId,sua.userId,sua.realName,pef.folwMomentId as folwMomentId
from sys_user_archive sua
INNER JOIN p_expense_flow pef ON pef.checkUserId =sua.userId
AND pef.expenseid=#{expenseId2}
</select>
低調小熊貓獨家解析
先給大家看一張圖，我就是靠這一張圖學會的
ok，這樣聰明的估計就學會了，不會的看上面程式碼吧
額，還是解釋幾個地方
<collection property="checkers"ofType="com.account.web.vo.admin.system.SysUserArchiveVo"
select="findChecker3" column="{expenseId2=expenseId}">
</collection>