这里讲的是人员和部门进行级联分布查询
1.首先在mybatis-config.xml里进行配置
<settings>
<!--显示的指定每个我们需要更改的配置的值，即使他是默认的。防止版本更新带来的问题 -->
<setting name="lazyLoadingEnabled" value="true"/>
<setting name="aggressiveLazyLoading" value="false"/>
</settings>
2 在department接口添加相关方法
public Department getDeptById(Integer id);
3在departmen映射文件中进行配置
<!--public Department getDeptById(Integer id); -->
<select >
select id,dname departmentName from department where id=#{id}
</select>
4在employee接口添加相关方法
public Employee getEmpByIdStep(Integer id);
5在departmen映射文件中进行配置
<!-- id last_name email gender d_id -->
<resultMap type="com.atguigu.mybatis.bean.Employee" >
select * from tbl_employee where id=#{id}
</select>
6在junit进行测试
Employee employee = mapper.getEmpByIdStep(1);
System.out.println(employee.getEmail());
运行结果如下：只有一条sql语句
Employee employee = mapper.getEmpByIdStep(1);
System.out.println(employee.getDept());
运行结果如下：有二条sql语句