mybatis的collection的使用_mybatis collection的用法-优快云博客

本文链接：https://blog.youkuaiyun.com/hcwbr123/article/details/79472437

本文详细介绍了MyBatis框架中Collection元素的使用方法，包括如何定义主查询与子查询，通过主查询结果作为子查询条件进行关联查询，以及如何在Java对象中映射这些查询结果。

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现象：
mybatis的collection的使用

方法：
1：主查询返回的map：
这里写图片描述
2：子查询返回对象的map

3：主查询sql语句

4：子查询语句

5：使用主查询返回的结果作为子查询的条件字段去子查询查询

6：接收数据对象，主对象中包含子对象中的集合

代码样例：

<resultMap type="com.oig.bean.SumDocuments" id="sumDocument">
        <result property="cid" column="cid"/>
        <result property="subscribedate" column="subscribedate"/>
        <result property="contractno" column="contractno"/>
        <result property="originplace" column="originplace"/>
        <result property="gnamedesc2" column="gnamedesc2"/>
        <result property="header" column="header"/>
        <result property="factoryno" column="factoryno"/>
        <result property="linkccode" column="linkccode"/>
        <result property="ccodetrust" column="ccodetrust"/>
        <result property="cname" column="cname"/>
        <result property="wname" column="wname"/>
        <result property="cpname" column="cpname"/>
        <result property="ordicode" column="ordicode"/>
        <collection property="list" column="{cid=cid,ordicode=ordicode}" javaType="ArrayList"  ofType="com.oig.bean.Documents" select="findDocumentByCid"/>
    </resultMap>
    <resultMap type="com.oig.bean.Documents" id="DocumentsMap">
        <result property="subscribedate" column="subscribedate"/>
                <result property="contractno" column="contractno"/>
                <result property="originplace" column="originplace"/>
                <result property="gnamedesc2" column="gnamedesc2"/>
                <result property="header" column="header"/>
                <result property="factoryno" column="factoryno"/>
                <result property="linkccode" column="linkccode"/>
                <result property="ccodetrust" column="ccodetrust"/>
                <result property="cname" column="cname"/>
                <result property="wname" column="wname"/>
                <result property="cpname" column="cpname"/>
                <result property="ordicode" column="ordicode"/>
    </resultMap>
    <select id="findsumDocumentBySql" parameterType="java.lang.String" resultMap="sumDocument">
        select 
            SUBSTRING(convert(varchar(100),max(subscribedate),20),1,10) as subscribedate,
            cid as cid,
            MAX(contractno) as contractno,
            MAX(originplace) as originplace,
            MAX(gnamedesc2) as gnamedesc2,
            MAX(header) as header,
            MAX(factoryno) as factoryno,
            MAX(linkccode) as linkccode,
            MAX(cname) as cname,
            MAX(wname) as wname,
            ordicode as ordicode,
            MAX(ccodetrust) as ccodetrust,
            MAX(cpname) as cpname
        from v_documents where 1=1 ${else_if} group by cid,ordicode
    </select>
    <select id="findDocumentByCid" parameterType="java.util.Map" resultMap="DocumentsMap">
        select * from v_documents where 1=1
         <choose>
        <when test="cid==null">
            and cid is null
        </when>
        <otherwise>
            and cid=#{cid}
        </otherwise>
        </choose>
         and ordicode=#{ordicode}
    </select>