mybatis表关联查询

作三张表的关联查询

cfm_requirement_vendor_date为cfm_requirement_vendor的子表 

cfm_requirement_vendor为cfm_requirement的子表 

一、mybatis映射文件定义

       <resultMap id="NestedRequirementResultMap"type="com.NestedRequirement"><result property="id" column="id" /><result property="requirementId" column="requirement_id" /><collection property="requirementVendorList"ofType="com.NestedRequirementVendor">    <result property="id" column="requirement_vendor_id" /> <result property="cfmRequirementId" column="cfm_requirement_id" /><result property="vendorId" column="vendor_id" /><collection property="requirementVendorDateList"ofType="com.RequirementVendorDate"><result property="id" column="requirement_vendor_date_id" /></collection></collection></resultMap>   <!-- 通过requirementId查询 --><select id="selectNestedByRequirementId" resultMap="NestedRequirementResultMap">SELECTr.id,r.requirement_id,v.id as requirement_vendor_id,v.vendor_id,d.id as requirement_vendor_date_id,FROMcfm_requirement rJOIN cfm_requirement_vendor v ON r.id = v.cfm_requirement_idAND v.del_flag = 0 join cfm_requirement_vendor_date d on v.id = d.cfm_requirement_vendor_id and d.del_flag=0 WHEREr.requirement_id = #{requirementId} and r.del_flag=0</select>

二、java类定义

1、mapper.java

List<NestedRequirement> selectNestedByRequirementId(int requirementId);

2、持久化对象

public class NestedRequirement extends Requirement {    private List<NestedRequirementVendor> requirementVendorList;public List<NestedRequirementVendor> getRequirementVendorList() {return requirementVendorList;}public void setRequirementVendorList(List<NestedRequirementVendor> requirementVendorList) {this.requirementVendorList = requirementVendorList;}      }