实体类:
public class Teacher {
private int id;
private String name;
}
public class Student {
private int id;
private String name;
private Teacher teacher;
}
Mapper接口
public interface StudentMapper {
List<Student> getStudent();
List<Student> getStudent2();
}
Mapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.cyk.dao.StudentMapper">
<!-- 子结果查询-->
<select id="getStudent" resultMap="StudentTeacher">
select * from student ;
</select>
<resultMap id="StudentTeacher" type="student">
<result column="id" property="id"/>
<result column="name" property="name"/>
<association column="tid" property="teacher" javaType="Teacher" select="getTeacher"/>
</resultMap>
<select id="getTeacher" resultType="teacher">
select * from teacher where id = #{id}
</select>
<!-- 联合查询-->
<select id="getStudent2" resultMap="StudentTeacher2">
select s.id sid,s.name sname, t.name tname
from student s,teacher t
where s.tid = t.id;
</select>
<resultMap id="StudentTeacher2" type="Student">
<result column="sid" property="id"/>
<result column="sname" property="name"/>
<association property="teacher" javaType="Teacher">
<result column="tname" property="name"/>
</association>
</resultMap>
</mapper>
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