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书接上文：mybatis流式查询
分享mybatis的结果映射配置的一对多查询方式：
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| <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ruben.mapper.UserMapper">
<resultMap id="userInfo" type="com.ruben.pojo.po.UserInfo">
<collection property="userRoles"
column="userRole.userId=id"
javaType="arraylist"
select="com.ruben.mapper.UserRoleMapper.selectListCursor"
fetchType="lazy"/>
</resultMap>
<select id="selectPageCursor" resultMap="userInfo">
select *
from user_info
</select>
</mapper>
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然后是UserRoleMapper对应的xml
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| <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ruben.mapper.UserRoleMapper">
<resultMap id="userRole" type="com.ruben.pojo.po.UserRole">
<result column="id" property="id"/>
<result column="user_id" property="userId"/>
<result column="role_id" property="roleId"/>
<association property="role"
column="id = role_id"
javaType="com.ruben.pojo.po.RoleInfo"
select="com.ruben.mapper.RoleMapper.getById"
fetchType="lazy"/>
</resultMap>
<select id="selectListCursor" resultMap="userRole">
select *
from user_role
<where>
<if test="userRole.userId != null">
AND user_id = #{userRole.userId}
</if>
<if test="userRole.roleId != null">
AND role_id = #{userRole.roleId}
</if>
</where>
</select>
</mapper>
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以及RoleMapper的
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| <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ruben.mapper.RoleMapper">
<resultMap id="roleInfo" type="com.ruben.pojo.po.RoleInfo">
<result column="id" property="id"/>
<result column="role_name" property="roleName"/>
</resultMap>
<select id="getById" resultMap="roleInfo">
select *
from role_info
where id = #{id}
</select>
</mapper>
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直接执行：
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| @Test
@SneakyThrows
void sqlSessionWay() {
Assertions.assertAll(() -> {
try (SqlSession session = sqlSessionFactory.openSession(); Cursor<UserInfo> userCursor = session.getMapper(UserMapper.class).selectPageCursor(new RowBounds(0, 5))) {
StreamSupport.stream(userCursor.spliterator(), true).forEach(System.out::println);
}
});
}
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输出：
完整代码：
https://gitee.com/VampireAchao/simple-mybatis.git