如果涉及动态sql，依然使用mapper.xml

mapper.xml和注解可以共存

1.使用注解时，mybatis.xml中<mappers>使用

（1）<package name="包名"/>

（2）<mapper class="包.接口类"/>

2.实现查询

@Select("select * from teacher")

List<Teacher> selAll();

2.修改

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

int updateTeacher(Teacher teacher);

3.删除

@Delete("delete from teacher where id=#{0"})

int delById(int id);

4.插入

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

int insTeacher(Teacher teacher);

注解实现<resultMap>功能，以N+1为例（查询该老师所有学生）

1.在StudentMapper接口添加查询

@Select("select * from student where tid=#{0}")

List<Student> selById(int tid);

2.在TeacherMapper接口添加

@Results()相当于<resultMap>

@Result()相当于id或result

@Result(id=true)相当于<id/>

@Many()相当于<collection/>

@On相当于<association>

@Results(value={@Result(id=true,property="id",column="id"),

@Result(property="name",column="name"),

@Result(property="list",column="id",many=@Many(select="com.bjsxt.StudentMapper.selById"))

})

@select(select * from teacher")

List<Teacher> selTeacher();