Java SMM框架关联关系映射示例讲解

目录

• 一、一对多关联关系
• 1.1 逆向生成代码配置文件
• 1.2 编写配置文件OrderMapper.xml
• 1.3 建立Vo类
• 二、多对对
• 2.1 逆向生成代码
• 2.2 创建Vo类

一、一对多关联关系

需求：通过订单号查询本次订单的详情信息以及对应的所有订单

1.1 逆向生成代码配置文件

generatorConfig.xml

1.2 编写配置文件OrderMapper.xml

  
    
      
      
    
  
  
    order_id, order_no
  
  
    
    
    
      
      
      
      
    
  
  
    select * from t_hibernate_order o,t_hibernate_order_item oi
    where o.order_id = oi.oid and o.order_id = #{orderId}
  
  
    select 
    
    from t_hibernate_order
    where order_id = #{orderId,jdbcType=INTEGER}
  
  
    delete from t_hibernate_order
    where order_id = #{orderId,jdbcType=INTEGER}
  
  
    insert into t_hibernate_order (order_id, order_no)
    values (#{orderId,jdbcType=INTEGER}, #{orderNo,jdbcType=VARCHAR})
  
  
    insert into t_hibernate_order
    
      
        order_id,
      
      
        order_no,
      
    
    
      
        #{orderId,jdbcType=INTEGER},
      
      
        #{orderNo,jdbcType=VARCHAR},
      
    
  
  
    update t_hibernate_order
    
      
        order_no = #{orderNo,jdbcType=VARCHAR},
      
    
    where order_id = #{orderId,jdbcType=INTEGER}
  
  
    update t_hibernate_order
    set order_no = #{orderNo,jdbcType=VARCHAR}
    where order_id = #{orderId,jdbcType=INTEGER}
  

1.3 建立Vo类

BookVo:

package com.xlb.ssm.model.vo;
import com.xlb.ssm.model.Order;
import com.xlb.ssm.model.OrderItem;
import java.util.List;
/**
 * Vo类不仅仅包含当前表的信息、还能包含相关联的表的信息
 *
 * 当前订单会有一个或者多个订单项，多个订单先必须要集合进行接受
 */
public class OrderVo extends Order {
    //需求1：通过订单号查询本次订单的详情信息及对应的所有订单
    private List orderItems;
    public List getOrderItems() {
        return orderItems;
    }
    public void setOrderItems(List orderItems) {
        this.orderItems = orderItems;
    }
}

BookItemVo：

package com.xlb.ssm.model.vo;
import com.xlb.ssm.model.Order;
import com.xlb.ssm.model.OrderItem;
import lombok.Data;
/**
 *
 * 某一个订单项一定属于某个订单的
 */
@Data
public class OrderItemVo extends OrderItem {
    private Order order;
    public Order getOrder() {
        return order;
    }
    public void setOrder(Order order) {
        this.order = order;
    }
}

添加@Data注释：省略了get、set、toString、构造方法。

再然后分别在OrderMapper.java 和 OrderBiz 里面添加查询的方法

    OrderVo queryOrderVoByOrderId(@Param("orderId") Integer orderId);

创建实现类OrderBizImpl

package com.xlb.ssm.biz.impl;
import com.xlb.ssm.biz.OrderBiz;
import com.xlb.ssm.mapper.OrderMapper;
import com.xlb.ssm.model.Order;
import com.xlb.ssm.model.vo.OrderVo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class OrderBizImpl implements OrderBiz {
    @Autowired
    private OrderMapper orderMapper;
    @Override
    public int deleteByPrimaryKey(Integer orderId) {
        return 0;
    }
    @Override
    public int insert(Order record) {
        return 0;
    }
    @Override
    public int insertSelective(Order record) {
        return 0;
    }
    @Override
    public Order selectByPrimaryKey(Integer orderId) {
        return null;
    }
    @Override
    public OrderVo queryOrderVoByOrderId(Integer orderId) {
        return orderMapper.queryOrderVoByOrderId(orderId);
    }
    @Override
    public int updateByPrimaryKeySelective(Order record) {
        return 0;
    }
    @Override
    public int updateByPrimaryKey(Order record) {
        return 0;
    }
}

测试类OrderBizImplTest

package com.xlb.ssm.biz.impl;
import com.xlb.ssm.biz.OrderBiz;
import com.xlb.ssm.model.Order;
import com.xlb.ssm.model.vo.OrderVo;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import static org.junit.Assert.*;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations={"classpath:applicationContext-mybatis.xml"})
public class OrderBizImplTest {
    @Autowired
    private OrderBiz orderBiz;
    //需求1：通过订单号查询本次订单的详情信息及对应的所有订单
    //select * from t_hibernate_order o,t_hibernate_order_item oi
    //where o.order_id = oi.oid and o.order_id = 9
    @Test
    public void queryOrderVoByOrderId() {
        OrderVo orderVo = orderBiz.queryOrderVoByOrderId(9);
        System.out.println(orderVo);
        //打印订单项
        System.out.println(orderVo.getOrderItems());
    }
}

结果

二、多对对

需求:根据书籍id，查询书籍信息以及所属类别信息；

2.1 逆向生成代码

配置要生成的实体类：generatorConfig.xml

2.2 创建Vo类

CategoryVo

package com.xlb.ssm.model.vo;
import com.xlb.ssm.model.Category;
import com.xlb.ssm.model.Hbook;
import lombok.Data;
import lombok.ToString;
import java.util.List;
@Data
public class CategoryVo extends Category {
    private List hbooks;
    public List getHbooks() {
        return hbooks;
    }
    public void setHbooks(List hbooks) {
        this.hbooks = hbooks;
    }
}

HbookVo

package com.xlb.ssm.model.vo;
import com.xlb.ssm.model.Category;
import com.xlb.ssm.model.Hbook;
import lombok.Data;
import java.util.List;
@Data
public class HbookVo extends Hbook {
    private List categories;
    public List getCategories() {
        return categories;
    }
    public void setCategories(List categories) {
        this.categories = categories;
    }
}

创建实现类：HbookCategoryBizImpl

package com.xlb.ssm.biz.impl;
import com.xlb.ssm.biz.HbookCategoryBiz;
import com.xlb.ssm.mapper.HbookCategoryMapper;
import com.xlb.ssm.model.HbookCategory;
import com.xlb.ssm.model.vo.CategoryVo;
import com.xlb.ssm.model.vo.HbookVo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class HbookCategoryBizImpl implements HbookCategoryBiz {
    @Autowired
    private HbookCategoryMapper hbookCategoryMapper;
    @Override
    public int deleteByPrimaryKey(Integer bcid) {
        return 0;
    }
    @Override
    public int insert(HbookCategory record) {
        return 0;
    }
    @Override
    public int insertSelective(HbookCategory record) {
        return 0;
    }
    @Override
    public HbookCategory selectByPrimaryKey(Integer bcid) {
        return null;
    }
    @Override
    public int updateByPrimaryKeySelective(HbookCategory record) {
        return 0;
    }
    @Override
    public int updateByPrimaryKey(HbookCategory record) {
        return 0;
    }
    @Override
    public HbookVo queryByBookId(Integer bookId) {
        return hbookCategoryMapper.queryByBookId(bookId);
    }
    @Override
    public CategoryVo queryByCid(Integer cid) {
        return hbookCategoryMapper.queryByCid(cid);
    }
}

然后再创建测试类进行测试：HbookCategoryBizImplTest

package com.xlb.ssm.biz.impl;
import com.xlb.ssm.biz.HbookCategoryBiz;
import com.xlb.ssm.model.vo.CategoryVo;
import com.xlb.ssm.model.vo.HbookVo;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import static org.junit.Assert.*;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations={"classpath:applicationContext-mybatis.xml"})
public class HbookCategoryBizImplTest {
    @Autowired
    private HbookCategoryBiz hbookCategoryBiz;
    @Test
    public void queryByBookId() {
        HbookVo hbookVo = hbookCategoryBiz.queryByBookId(8);
        System.out.println(hbookVo);
    }
    @Test
    public void queryByCid() {
        CategoryVo categoryVo = hbookCategoryBiz.queryByCid(8);
        System.out.println(categoryVo);
    }
}

结果

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