MybatisMapper配置

mysql
mysql-connector-java
5.1.32


org.mybatis
mybatis
3.4.6


junit
junit
4.12


log4j
log4j
1.2.17

1.1 一对一查询

 

 

 

 

 

 

 

 

 

 

 

 

5. 配置OrderMapper.xml



 





 

select * from orders o,user u where o.uid=u.id



6. 测试结果

OrderMapper mapper = sqlSession.getMapper(OrderMapper.class);List all = mapper.findAll();for(Order order : all){ System.out.println(order);}

 

 

 

 

 

 

 

 

 

 

 

 

4. 创建UserMapper接口

public interface UserMapper { List findAll();}

5. 配置UserMapper.xml

select *,o.id oid from user u left join orders o on u.id=o.uid

一对多查询

UserMapper mapper = sqlSession.getMapper(UserMapper.class);

List all = mapper.findAll();

for(User user : all){

System.out.println(user.getUsername());

 List orderList = user.getOrderList();

 for(Order order : orderList){ System.out.println(order);

 }

System.out.println("----------------------------------");}

 

 

 

 

 

4. 添加UserMapper接口方法

List findAllUserAndRole();

配置UserMapper.xml



  













select u.*,r.*,r.id rid from user u left join user_role ur on u.id=ur.user_id inner join role r on ur.role_id=r.id

 

6. 测试结果

UserMapper mapper = sqlSession.getMapper(UserMapper.class);

List all = mapper.findAllUserAndRole();

for(User user : all){

System.out.println(user.getUsername());

 List roleList = user.getRoleList();

for(Role role : roleList){

System.out.println(role); }

System.out.println("----------------------------------");

}