MyBatis的基本注解 | 易学教程

MyBatis的基本注解：

增删改查

@Select("select * from teacher")

 public List<Teacher> selAll();

 

 //增删改返回值都是int

 @Insert("insert into teacher values(default,#{name})")

 public int add(Teacher teacher);

 

 @Update("update teacher set name=#{name} where id=#{id}")

 public int update(Teacher teacher);

 

 @Delete("delete from teacher where id=#{id}")

 public int delete(int id);

注解映射：

1.普通映射

@Select("select * from mybatis_Student where id=#{id}")
public Student getStudent(int id);
@Insert("insert into mybatis_Student (name, age, remark, pic,grade_id,address_id) values (#{name},#{age},#{remark}, #{pic},#{grade.id},#{address.id})")
public int insert(Student student);
@Update("update mybatis_Student set name=#{name},age=#{age} where id=#{id}")
public int update(Student student);
@Delete("delete from mybatis_Student where id=#{id}")
public int delete(int id);

2.结果集映射

@Select("select * from mybatis_Student")
@Results({
@Result(id=true,property="id",column="id"),
@Result(property="name",column="name"),
@Result(property="age",column="age")
})
public List<Student> getAllStudents();

３.关系映射

3.1一对一

@Select("select * from mybatis_Student")
@Results({
@Result(id=true,property="id",column="id"),
@Result(property="name",column="name"),
@Result(property="age",column="age"),
@Result(property="address",column="address_id",one=@One(select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))
})
public List<Student> getAllStudents();

3.2一对多

@Select("select * from mybatis_grade where id=#{id}")
@Results({
@Result(id=true,column="id",property="id"),
@Result(column="grade_name",property="gradeName"),
@Result(property="students",column="id",many=@Many(select="com.skymr.mybatis.mappers.Student2Mapper.getStudentsByGradeId"))
})
public Grade getGrade(int id);