mybatis collection 多条件查询的实现方法
前言:
业务需要通过mybatis 查询返回嵌套集合,嫌多次查询太麻烦,用自带的高级查询解决问题,下边是代码,已测试通过。
说下自己的理解,就是一个主查询结果集里面嵌套了子查询的结果集,可以是多个子查询,每个子查询的条件从主查询结果集中获取,返回值各自定义。collection 标签的property是主查询里面集合的名字,如果有多个就再写个collection,column是子查询参数,单参数直接写主查询结合返回结果,例如直接写上user_id,要是数据库的字段,多条件就封装下,例如{userId=user_id,theme=theme},然后子查询的parameterType写"java.util.Map",多条件查询好像只有mybatis3.0以后才有,看网上资料说的,没验证过,ofType是集合里的对象,select是对应下面的语句
实现代码:
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<resultMap id= "BaseResultMap" type= "web.model.UserMessage" > <id column = "id" property= "id" jdbcType= "INTEGER" /> <result column = "user_id" property= "userId" jdbcType= "INTEGER" /> <result column = "theme" property= "theme" jdbcType= "VARCHAR" /> <result column = "status" property= "status" jdbcType= "INTEGER" /> <result column = "theme_time" property= "themeTime" jdbcType= "TIMESTAMP" /> <result column = "create_time" property= "createTime" jdbcType= "TIMESTAMP" /> <result column = "update_time" property= "updateTime" jdbcType= "TIMESTAMP" /> <result column = "yn" property= "yn" jdbcType= "INTEGER" /> </resultMap> <resultMap id= "BaseVoResultMap" type= "web.model.vo.UserMessageVo" extends= "BaseResultMap" > <collection property= "userMessageDetailList" column = "{userId=user_id,theme=theme}" javaType= "java.util.ArrayList" ofType= "web.model.UserMessageDetail" select = "selectUserMessageDetailById" /> </resultMap> <resultMap id= "BaseDetailResultMap" type= "web.model.UserMessageDetail" > <id column = "id" property= "id" jdbcType= "INTEGER" /> <result column = "user_message_id" property= "userMessageId" jdbcType= "INTEGER" /> <result column = "sponsor_id" property= "sponsorId" jdbcType= "INTEGER" /> <result column = "user_id" property= "userId" jdbcType= "INTEGER" /> <result column = "user_type" property= "userType" jdbcType= "INTEGER" /> <result column = "provider_id" property= "providerId" jdbcType= "INTEGER" /> <result column = "message" property= "message" jdbcType= "VARCHAR" /> <result column = "status" property= "status" jdbcType= "INTEGER" /> <result column = "message_time" property= "messageTime" jdbcType= "TIMESTAMP" /> <result column = "create_time" property= "createTime" jdbcType= "TIMESTAMP" /> <result column = "update_time" property= "updateTime" jdbcType= "TIMESTAMP" /> <result column = "yn" property= "yn" jdbcType= "INTEGER" /> </resultMap> < select id= "selectUserMessageById" resultMap= "BaseVoResultMap" parameterType= "java.lang.Integer" > select * from user_message where user_id = #{userId,jdbcType= INTEGER } </ select > < select id= "selectUserMessageDetailById" resultMap= "BaseDetailResultMap" parameterType= "java.util.Map" > select * from user_message_detail where user_id = #{userId,jdbcType= INTEGER } and message = #{theme,jdbcType= VARCHAR } </ select > |
selectUserMessageById,这个是主查询,VO只多了个 private List<UserMessageDetail> userMessageDetailList,
这个属性,下面是返回值结构截图
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原文链接:http://blog.csdn.net/di315362886/article/details/60144410