Mybatis 多对多注解 查询

学习mybatis多对多注解，记录下来以便日后查询。
这里多对多关系用到了学生(student)和课程(course)，一个学生可以选多门课，一门课可以被多名学生选择，中间表stu_cou.
Student.java

public class Student {    private int id;    private String name;    private Classes classes;    private List<Course> courseList;    //getter and setter    }

Course.java

public class Course {    private int id;    private String name;    private int credit;    private List<Student> studentList;    //getter and setter    }

StudentMapper.java,在其中添加通过courseId查询student的select语句：

    @Select("select * from student where id in(select stu_id from stu_cou where cou_id=#{courseId})")    @Results({        @Result(id=true,property="id",column="id"),        @Result(property="name",column="name"),        @Result(property="classes",column="classes_id",javaType=Classes.class,        one=@One(select="com.lsj.test.mybatis.annotation.mapper.ClassesMapper.selectClasses",fetchType=FetchType.LAZY)),        @Result(property="courseList",column="id",many=@Many(select="com.lsj.test.mybatis.annotation.mapper.CourseMapper.selectCourseByStudent",fetchType=FetchType.LAZY))    })    public List<Student> selectStudentByCourse(int courseId);

CourseMapper.java中添加通过学生Id查询Course的select语句

    @Select("select * from course where id in(select cou_id from stu_cou where stu_id=#{studentId})")    @Results({        @Result(id=true,property="id",column="id"),        @Result(property="name",column="name"),        @Result(property="credit",column="credit"),        @Result(property="studentList",column="id",        many=@Many(select="com.lsj.test.mybatis.annotation.mapper.StudentMapper.selectStudentByCourse",fetchType=FetchType.LAZY))        })    public List<Course> selectCourseByStudent(int studentId);

之后在StudentMapper.java中的select语句中的Result添加many，指向CourseMapper中的通过学生Id查询Course的select语句，同理CourseMapper也是一样的操作指向StudentMapper。

    @Select("select * from student where id=#{id}")    @Results({        @Result(id=true,property="id",column="id"),        @Result(property="name",column="name"),        @Result(property="classes",column="classes_id",javaType=Classes.class,        one=@One(select="com.lsj.test.mybatis.annotation.mapper.ClassesMapper.selectClasses")),//这里添加many，指向CourseMapper中的selectCourseByStudent查询语句        @Result(property="courseList",column="id",many=@Many(select="com.lsj.test.mybatis.annotation.mapper.CourseMapper.selectCourseByStudent",fetchType=FetchType.LAZY))    })    public Student selectStudent(int id);