最近學習mybatis，記錄下一對多關聯註解。
這裡用班級(Classes)和學生(Student)一對多關聯，配置如下：
Classes.java

public class Classes {
    public int id;
    public String name;
    public List<Student> studentList;
    //getter/setter
    }

Student.java

public class Student {
    private int id;
    private String name;
    private
 
 Classes classes;
    //getter/setter
    }

ClassesMapper.java

public interface ClassesMapper {

    @Insert("insert into classes (name) values (#{name})")
    @Options(useGeneratedKeys=true,keyProperty="id")
    public void insertClasses(Classes classes);

    @Select("select * from classes where id=#{id}"
 
)
    @Results({
        @Result(id=true,property="id",column="id"),
        @Result(property="name",column="name"),
        @Result(property="studentList",column="id",javaType=List.class,
        many=@Many(select="com.lsj.test.mybatis.annotation.mapper.StudentMapper.selectStudentByClass"))
    })
    public
 
 Classes selectClasses(int id);

    @Delete("delete from classes where id=#{id}")
    public void deleteClasses(int id);

}

StudentMapper.java

public interface StudentMapper {

    @Insert("insert into student (name,classes_id) values(#{name},#{classes.id})")
    @Options(useGeneratedKeys=true,keyProperty="id")
    public void insertStudent(Student student);

    @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"))
    })
    public Student selectStudent(int id);

    @Select("select * from student where classes_id=#{classId}")
    @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"))
    })
    public List<Student> selectStudentByClass(int classId);

    @Delete("delete from student where id=#{id}")
    public void deleteStudent(int id);
}

這裡StudentMapper中，Student中包含classes物件，是多端，通過

        @Result(property="classes",column="classes_id",javaType=Classes.class,
        one=@One(select="com.lsj.test.mybatis.annotation.mapper.ClassesMapper.selectClasses")

把student與classes聯絡起來，這樣查詢student時，根據classes_id就可以加上classes查詢並加入到student中

在ClassesMapper中查詢studentList時，引用了StudentMapper中通過班級Id查詢Student的select語句

@Result(property="studentList",column="id",javaType=List.class,
        many=@Many(select="com.lsj.test.mybatis.annotation.mapper.StudentMapper.selectStudentByClass")

其中many語句需要在StudentMapper定義一個根據班級id查學生的select語句，上面的Result的many中column必須是班級表的id，把班級id傳給select語句作為引數。