1在人员接口实现方法
public Employee getEmpByIdStep(Integer id);
2在映射文件进行配置
<!-- public Employee getEmpByIdStep(Integer id);-->
<select >
select * from tbl_employee where id=#{id}
</select>
3写鉴别器
<!-- <discriminator javaType=""></discriminator>
鉴别器：mybatis可以使用discriminator判断某列的值，然后根据某列的值改变封装行为
封装Employee：
如果查出的是女生：就把部门信息查询出来，否则不查询；
如果是男生，把last_name这一列的值赋值给email;
-->
<resultMap type="com.atguigu.mybatis.bean.Employee" />
</case>
</discriminator>
</resultMap>
3在junit进行测试
@Test
public void test05() throws IOException{
SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
SqlSession openSession = sqlSessionFactory.openSession();
try{
EmployeeMapperPlus mapper = openSession.getMapper(EmployeeMapperPlus.class);
Employee employee = mapper.getEmpByIdStep(4);
System.out.println(employee);
System.out.println(employee.getDept());
}finally{
openSession.close();
}
}
结果如下：
@Test
public void test05() throws IOException{
SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
SqlSession openSession = sqlSessionFactory.openSession();
try{
EmployeeMapperPlus mapper = openSession.getMapper(EmployeeMapperPlus.class);
Employee employee = mapper.getEmpByIdStep(1);
System.out.println(employee);
System.out.println(employee.getDept());
}finally{
openSession.close();
}
}
结果如下：