多对多

package cn.itcast.mybatis.po;

import java.util.Date;

public class Items {
private Integer id;
private String name;
private float price;
public Integer getId() {
    return id;
}
public void setId(Integer id) {
    this.id = id;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public float getPrice() {
    return price;
}
public void setPrice(float price) {
    this.price = price;
}
public String getDetail() {
    return detail;
}
public void setDetail(String detail) {
    this.detail = detail;
}
public String getPic() {
    return pic;
}
public void setPic(String pic) {
    this.pic = pic;
}
public Date getCreatetime() {
    return createtime;
}
public void setCreatetime(Date createtime) {
    this.createtime = createtime;
}
private String detail;
private String pic;
private Date createtime;

}

package cn.itcast.mybatis.po;



public class Orderdetail {
    private int id;
    private int orders_id;
    private int items_id;
    private int items_num;
    //商品（一个明细对应一个商品）
    private Items items;
    public int getItems_num() {
        return items_num;
    }
    public void setItems_num(int items_num) {
        this.items_num = items_num;
    }
    public Items getItems() {
        return items;
    }
    public void setItems(Items items) {
        this.items = items;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public int getOrders_id() {
        return orders_id;
    }
    public void setOrders_id(int orders_id) {
        this.orders_id = orders_id;
    }
    public int getItems_id() {
        return items_id;
    }
    public void setItems_id(int items_id) {
        this.items_id = items_id;
    }

    

}

package cn.itcast.mybatis.po;

import java.util.Date;
import java.util.List;

public class Orders {
private Integer id;
private Integer user_id;
private String number;
private Date createtime;
private String note;
//用户信息，新增了一个User属性，为了保存查询得到的关联的User表的信息(一对一)
private User user;
//订单明细。order关联多个orderdetails，（一对多）
private List<Orderdetail> orderdetails;


public List<Orderdetail> getOrderdetail() {
    return orderdetails;
}
public void setOrderdetail(List<Orderdetail> orderdetail) {
    this.orderdetails = orderdetail;
}
public User getUser() {
    return user;
}
public void setUser(User user) {
    this.user = user;
}
public Integer getId() {
    return id;
}
public void setId(Integer id) {
    this.id = id;
}
public Integer getUser_id() {
    return user_id;
}
public void setUser_id(Integer user_id) {
    this.user_id = user_id;
}
public String getNumber() {
    return number;
}
public void setNumber(String number) {
    this.number = number;
}
public Date getCreatetime() {
    return createtime;
}
public void setCreatetime(Date createtime) {
    this.createtime = createtime;
}
public String getNote() {
    return note;
}
public void setNote(String note) {
    this.note = note;
}


}

package cn.itcast.mybatis.po;

import java.util.Date;
import java.util.List;

public class User {
private int id;//对应数据库中主键
private String username;//对应数据库中用户的名称
private Date birthday;//对应数据库中的生日
private String sex;//性别
private String address;//地址
//一个用户对应多个订单表
private List<Orders> ordersList;
public List<Orders> getOrdersList() {
    return ordersList;
}
public void setOrdersList(List<Orders> ordersList) {
    this.ordersList = ordersList;
}
public int getId() {
    return id;
}
public void setId(int id) {
    this.id = id;
}
public String getUsername() {
    return username;
}
public void setUsername(String username) {
    this.username = username;
}
public Date getBirthday() {
    return birthday;
}
public void setBirthday(Date birthday) {
    this.birthday = birthday;
}
public String getSex() {
    return sex;
}
public void setSex(String sex) {
    this.sex = sex;
}
public String getAddress() {
    return address;
}
public void setAddress(String address) {
    this.address = address;
}

}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- nanmespace:命名空间。 作用就是对sql进行分类话管理，理解Sal分离

注意：使用mapper代理方式，namespace有特殊重要的作用
-->

<mapper namespace="cn.itcast.mybatis.mapper.OrdersMapperCustom">
  

    
    
    
    <!-- 这个很有意思， resultMap里面套collection1，collection1里面再套collection2，collection2里面再套association-->
    
     <resultMap type="cn.itcast.mybatis.po.User" id="UserAndItemsResultMap">
         
        <!-- 用户信息 
        <id 要确定User表的唯一性，user_id是来自order表中的user_id字段，
        property="id"表示映射到cn.itcast.mybatis.po.User中的id属性
         我们做的只是再给数据库查出来的数据做映射，所以这一次的一切的依据就是查出来的表，我们要给查出来的表
         的每一个字段做好映射
        -->
        <id column="user_id"  property="id"/>  
        <!-- 
        
        result是我们需要的数据    对它映射
         -->
         <result column="username" property="username"/>
             <result column="sex" property="sex"/>
        <result column="address" property="address"/>
        
        <!-- 订单信息
        一个用户对应多个订单，使用collection映射
         -->
         <collection property="ordersList" ofType="cn.itcast.mybatis.po.Orders">
             <id column="id" property="id"/>
             <result column="user_id" property="user_id"/>
            <result column="number" property="number"/>
            <result column="createtime" property="createtime"/>
            <result column="note" property="note"/>
            
             <!-- 订单明细
         一个订单包括 多个明细 使用collection映射
          -->
              <collection property="orderdetails" ofType="cn.itcast.mybatis.po.Orderdetail">
                      <id column="orderdetail_id" property="id"/>
                     <result column="items_id" property="items_id"/>
                     <result column="items_num" property="items_num"/>
                     <result column="orders_id" property="orders_id"/>
                     
                     <!-- 商品信息
              一个订单明细对应一个商品 使用association映射
               -->
                   <association property="items" javaType="cn.itcast.mybatis.po.Items">
                       <id column="items_id" property="id"/>
                       <result column="items_name" property="name"/>
                       <result column="items_detail" property="detail"/>
                       <result column="items_price" property="price"/>
                   </association>
                     
              </collection>
         </collection>
         
         
         
         
         
         
     </resultMap>
   
    
    
    
      
      <select id="findUserAndItemsResultMap" resultMap="UserAndItemsResultMap">
         SELECT 
  orders.*,
  USER.username,
  USER.sex,
  USER.address,
  orderdetail.id orderdetail_id,
  orderdetail.items_id,
  orderdetail.items_num,
  orderdetail.orders_id,
  items.name items_name,
  items.detail items_detail,
  items.price items_price
FROM
  orders,
  USER,
  orderdetail,
  items
WHERE orders.user_id = user.id AND orderdetail.orders_id=orders.id AND orderdetail.items_id = items.id
          
          
          
          
          
      </select>
      
      
</mapper>

package cn.itcast.mybatis.mapper;

import java.util.List;

import cn.itcast.mybatis.po.Orders;
import cn.itcast.mybatis.po.OrdersCustom;
import cn.itcast.mybatis.po.User;

public interface OrdersMapperCustom {
    //函数的名字OrdersMapperCustom.xml中select中的id名一样
    public List<OrdersCustom> findOrdersUser();
    public List<Orders> findOrdersUseResultMap();
    public List<Orders> findOrdersandOrderDetailResultMap();
public List<User> findUserAndItemsResultMap();
}

package cn.itcast.mybatis.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;

import cn.itcast.mybatis.mapper.OrdersMapperCustom;
import cn.itcast.mybatis.mapper.userMapper;
import cn.itcast.mybatis.po.Orders;
import cn.itcast.mybatis.po.User;
import cn.itcast.mybatis.po.UserCustom;
import cn.itcast.mybatis.po.UserQueryVo;

public class Mybatis_mappertest {
    
    private SqlSessionFactory sqlSessionFactory;
    @Before
    public void setup() throws IOException
    {   String resource="SqlMapConfig.xml";
        InputStream inputStream= Resources.getResourceAsStream(resource);
        //主要是生成SqlsessionFactory。
        this.sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
    }
    @Test
    public void testMaper()
    {
        SqlSession sqlSession=null;
        
        sqlSession=sqlSessionFactory.openSession();
        //生成代理类
        OrdersMapperCustom orderMapper=sqlSession.getMapper(OrdersMapperCustom.class);
    //创建包装对象，设置查询条件
        //orderMapper.findOrdersUser();
        
       @SuppressWarnings("unused")
    
        List<User> list=orderMapper.findUserAndItemsResultMap();
    
    
    
    
    }

}