mybatis关联关系映射

1、一对多关联关系

2、多对多关联关系

首先先用逆向生成工具生成t_hibernate_order、t_hibernate_order_item

t_hibernate_book、t_hibernate_book_category、t_hibernate_category

这五张表对应的model与mapper

配置mybatis-generator插件生成文件位置
修改generatorConfig.xml配置文件的生成目录(mapper和model)及对应生成关系

创建实体类：

package com.lingerqi.model.vo;

import com.lingerqi.model.Horder;
import com.lingerqi.model.Horderitem;

import java.util.ArrayList;
import java.util.List;

/**
 * @author xyls
 * @create  2019-10-23 10:43
 */
public class OrderVo extends Horder {


    private List<Horderitem> horderitems = new ArrayList<>();

    public List<Horderitem> getHorderitems() {
        return horderitems;
    }

    public void setHorderitems(List<Horderitem> horderitems) {
        this.horderitems = horderitems;
    }
    @Override
    public String toString() {
        return "OrderVo{" +
                "horderitems=" + horderitems +
                '}';
    }
}

　　

package com.lingerqi.model.vo;

import com.lingerqi.model.Horder;
import com.lingerqi.model.Horderitem;

/**
 * @author xyls
 * @create  2019-10-23 10:46
 */
public class HorderitemVo extends Horderitem {
    private Horder horder;


    public Horder getHorder() {
        return horder;
    }

    public void setHorder(Horder horder) {
        this.horder = horder;
    }

    @Override
    public String toString() {
        return "HorderitemVo{" +
                "horder=" + horder +
                '}';
    }
}

　　HorderMapper.xml:

 <resultMap id="OrderVoMap" type="com.lingerqi.model.vo.OrderVo" >
    <result property="orderId" column="order_id"></result>
    <result property="orderNo" column="order_no"></result>
    <collection property="orderItems" ofType="com.lingerqi.model.Horderitem">
      <result property="orderItemId" column="order_item_id"></result>
      <result property="oid" column="oid"></result>
      <result property="productId" column="product_id"></result>
      <result property="quantity" column="quantity"></result>
    </collection>
  </resultMap>
<select id="selectByOrderId" resultMap="OrderVoMap" parameterType="java.lang.Integer">
   select * from t_hibernate_order o,t_hibernate_order_item oi where o.ordre_id=oi.oid
   and oi.order_id=#{orderId}
  </select>

　　

@Repository
public interface HorderMapper {
  List<OrderVo> selectByOrderId(@Param("orderId") Integer orderId);
}

　　HorderitemMapper.xml

<resultMap id="OrderItemVoMap" type="com.lingerqi.model.vo.HorderitemVo">

    <result property="orderItemId" column="order_item_id"></result>
    <result property="productId" column="product_id"></result>
    <result property="quantity" column="quantity"></result>
    <result property="oid" column="oid"></result>
    <!--<result property="orderItems"></result>-->
    <association property="order" javaType=" com.lingerqi.model.Horder">
      <result property="orderId" column="order_id"></result>
      <result property="orderNo" column="order_no"></result>
    </association>
  </resultMap>
<select id="selectByOrderItemId" resultMap="OrderItemVoMap" parameterType="java.lang.Integer">
   select * from t_hibernate_order o,t_hibernate_order_item oi where o.ordre_id=oi.oid
   and oi.order_item_id =#{orderItemId}
  </select>　

　　

@Repository
public interface HorderitemMapper {
   List<HorderitemVo> selectByOrderItemId(@Param("orderItemId") Integer orderItemId);
}

　　

package com.lingerqi.Service;


import com.lingerqi.model.vo.HorderitemVo;
import com.lingerqi.model.vo.OrderVo;

import java.util.List;

/**
 * @auther xyls
 * @create 2019-10-23-18:19
 */
public interface OneToManyService {
    List<OrderVo> selectByOrderId(Integer orderId);

    List<HorderitemVo> selectByOrderItemId(Integer orderItemId);

}

　　

public class OneToManyServiceImplTest extends SpringBaseTest {
    @Autowired
    private OneToManyService oneToManyService;

    @Test
    public void selectByOrderId() {
        List<OrderVo> orderVos = oneToManyService.selectByOrderId(8);
        OrderVo orderVo=orderVos.get(0);
        System.out.println(orderVos);
        for (OrderItem orderItem : orderVo.getOrderItems()) {
            System.out.println(orderItem);
        }
    }

    @Test
    public void selectByOrderItemId() {
        List<OrderItemVo> orderItemVos = oneToManyService.selectByOrderItemId(36);
        OrderItemVo orderItemVo=orderItemVos.get(0);
        System.out.println(orderItemVo);
        System.out.println(orderItemVo.getOrder());
    }
}

　　

package com.lingerqi.mapper;

import com.lingerqi.model.HbookCategory;

public interface HbookCategoryMapper {
    int deleteByPrimaryKey(Integer bcid);

    int insert(HbookCategory record);

    int insertSelective(HbookCategory record);

    HbookCategory selectByPrimaryKey(Integer bcid);

    int updateByPrimaryKeySelective(HbookCategory record);

    int updateByPrimaryKey(HbookCategory record);
}

　　

package com.lingerqi.service.impl;

import com.lingerqi.service.ManyToManyService;
import com.lingerqi.mapper.CategoryMapper;
import com.lingerqi.mapper.HbookMapper;
import com.lingerqi.model.vo.CategoryVo;
import com.lingerqi.model.vo.HbookVo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/**
 * @auther xyls
 * @create 2019-10-24-11:11
 */
@Service
public class ManyToManyServiceImpl implements ManyToManyService {
    @Autowired
    private HbookMapper hbookMapper;
    @Autowired
    private CategoryMapper categoryMapper;
    @Override
    public HbookVo selectByBid(Integer bid) {
        return hbookMapper.selectByBid(bid);
    }

    @Override
    public CategoryVo selectByCid(Integer cid) {
        return categoryMapper.selectByCid(cid);
    }
}

　　

package com.lingerqi.service.impl;

import com.lingerqi.SpringBaseTest;
import com.lingerqi.model.Category;
import com.lingerqi.model.Hbook;
import com.lingerqi.model.vo.CategoryVo;
import com.lingerqi.model.vo.HbookVo;
import com.lingerqi.service.ManyToManyService;
import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;

/**
 * @auther xyls
 * @create 2019-10-24-11:13
 */
public class ManyToManyServiceImplTest extends SpringBaseTest {

    @Autowired
    private ManyToManyService manyToManyService;
    @Test
    public void selectByBid() {
        HbookVo hbookVo=manyToManyService.selectByBid(8);
        System.out.println(hbookVo);
        for (Category category : hbookVo.getCategories()) {
            System.out.println(category);
        }
    }

    @Test
    public void selectByCid() {
        CategoryVo categoryVo = this.manyToManyService.selectByCid(8);
        System.out.println(categoryVo);
        for (Hbook hbook : categoryVo.getHbooks()) {
            System.out.println(hbook);
        }

    }
}