• MyBatis之关联关系

    目录

    一、一对多关联关系

    1、实体类

    ②OrderItem

    2、Biz层

    ①OrderBiz

    3、Biz的实现层Impl

    ①OrderBizImpl

    ②OrderItemBizImpl

    4、mapper层

    ①OrderMapper.java

    ②OrderMapper.xml

    ③OrderItemMapper.java

    一、一对多关联关系

    1、实体类

    首先先用逆向生成工具生成t_hibernate_order、t_hibernate_order_item
    这两张表对应的model与mapper 

    ①Order 

    1. package com.chenchen.ssm.model;
    2.  
    3. import lombok.AllArgsConstructor;
    4. import lombok.Data;
    5. import lombok.NoArgsConstructor;
    6.  
    7. //t_hibernate_order
    8. //相当于添加了set/get方法，同时添加tostring
    9. //@NoArgsConstructor
    10. //@AllArgsConstructor
    11. @Data
    12. public class Order {
    13.     private Integer orderId;
    14.  
    15.     private String orderNo;
    16.  
    17. }

    ②OrderItem

    1. package com.chenchen.ssm.model;
    2.  
    3. import lombok.Data;
    4. import lombok.ToString;
    5.  
    6. @ToString
    7. public class OrderItem {
    8.     private Integer orderItemId;
    9.  
    10.     private Integer productId;
    11.  
    12.     private Integer quantity;
    13.  
    14.     private Integer oid;
    15.  
    16.     public OrderItem(Integer orderItemId, Integer productId, Integer quantity, Integer oid) {
    17.         this.orderItemId = orderItemId;
    18.         this.productId = productId;
    19.         this.quantity = quantity;
    20.         this.oid = oid;
    21.     }
    22.  
    23.     public OrderItem() {
    24.         super();
    25.     }
    26.  
    27.     public Integer getOrderItemId() {
    28.         return orderItemId;
    29.     }
    30.  
    31.     public void setOrderItemId(Integer orderItemId) {
    32.         this.orderItemId = orderItemId;
    33.     }
    34.  
    35.     public Integer getProductId() {
    36.         return productId;
    37.     }
    38.  
    39.     public void setProductId(Integer productId) {
    40.         this.productId = productId;
    41.     }
    42.  
    43.     public Integer getQuantity() {
    44.         return quantity;
    45.     }
    46.  
    47.     public void setQuantity(Integer quantity) {
    48.         this.quantity = quantity;
    49.     }
    50.  
    51.     public Integer getOid() {
    52.         return oid;
    53.     }
    54.  
    55.     public void setOid(Integer oid) {
    56.         this.oid = oid;
    57.     }
    58. }

    2、Biz层

    ①OrderBiz

    1. package com.chenchen.ssm.biz;
    2.  
    3. import com.chenchen.ssm.model.Book;
    4. import com.chenchen.ssm.model.BookVo;
    5. import com.chenchen.ssm.model.Order;
    6. import com.chenchen.ssm.model.vo.OrderVo;
    7. import com.chen.ssm.util.PageBean;
    8. import org.apache.ibatis.annotations.Param;
    9.  
    10. import java.util.List;
    11. import java.util.Map;
    12.  
    13. public interface OrderBiz {
    14.     int deleteByPrimaryKey(Integer orderId);
    15.  
    16.     int insert(Order record);
    17.  
    18.     int insertSelective(Order record);
    19.  
    20.     Order selectByPrimaryKey(Integer orderId);
    21.  
    22.     OrderVo queryOrderVoByOrderId(Integer orderId);
    23.  
    24.     int updateByPrimaryKeySelective(Order record);
    25.  
    26.     int updateByPrimaryKey(Order record);
    27. }
    28.

    3、Biz的实现层Impl

    ①OrderBizImpl

    1. package com.chenchen.ssm.biz.impl;
    2.  
    3. import com.chenchen.ssm.biz.OrderBiz;
    4. import com.chenchen.ssm.mapper.OrderMapper;
    5. import com.chenchen.ssm.model.Order;
    6. import com.chenchen.ssm.model.vo.OrderVo;
    7. import org.springframework.beans.factory.annotation.Autowired;
    8. import org.springframework.stereotype.Service;
    9.  
    10. @Service
    11. public class OrderBizImpl implements OrderBiz {
    12.     @Autowired
    13.     private OrderMapper orderMapper;
    14.     @Override
    15.     public int deleteByPrimaryKey(Integer orderId) {
    16.         return 0;
    17.     }
    18.  
    19.     @Override
    20.     public int insert(Order record) {
    21.         return 0;
    22.     }
    23.  
    24.     @Override
    25.     public int insertSelective(Order record) {
    26.         return 0;
    27.     }
    28.  
    29.     @Override
    30.     public Order selectByPrimaryKey(Integer orderId) {
    31.         return null;
    32.     }
    33.  
    34.     @Override
    35.     public OrderVo queryOrderVoByOrderId(Integer orderId) {
    36.         return orderMapper.queryOrderVoByOrderId(orderId);
    37.     }
    38.  
    39.     @Override
    40.     public int updateByPrimaryKeySelective(Order record) {
    41.         return 0;
    42.     }
    43.  
    44.     @Override
    45.     public int updateByPrimaryKey(Order record) {
    46.         return 0;
    47.     }
    48. }
    49.

    ②OrderItemBizImpl

    1. package com.chenchen.ssm.biz.impl;
    2.  
    3. import com.chenchen.ssm.biz.OrderItemBiz;
    4. import com.chenchen.ssm.mapper.OrderItemMapper;
    5. import com.chenchen.ssm.model.OrderItem;
    6. import com.chenchen.ssm.model.vo.OrderItemVo;
    7. import org.springframework.beans.factory.annotation.Autowired;
    8. import org.springframework.stereotype.Service;
    9.  
    10. @Service
    11. public class OrderItemBizImpl implements OrderItemBiz {
    12.     @Autowired
    13.     private OrderItemMapper orderItemMapper;
    14.     @Override
    15.     public int deleteByPrimaryKey(Integer orderItemId) {
    16.         return 0;
    17.     }
    18.  
    19.     @Override
    20.     public int insert(OrderItem record) {
    21.         return 0;
    22.     }
    23.  
    24.     @Override
    25.     public int insertSelective(OrderItem record) {
    26.         return 0;
    27.     }
    28.  
    29.     @Override
    30.     public OrderItem selectByPrimaryKey(Integer orderItemId) {
    31.         return null;
    32.     }
    33.  
    34.     @Override
    35.     public OrderItemVo queryOrderItemVoByOrderItemId(Integer orderItemId) {
    36.         return orderItemMapper.queryOrderItemVoByOrderItemId(orderItemId);
    37.     }
    38.  
    39.     @Override
    40.     public int updateByPrimaryKeySelective(OrderItem record) {
    41.         return 0;
    42.     }
    43.  
    44.     @Override
    45.     public int updateByPrimaryKey(OrderItem record) {
    46.         return 0;
    47.     }
    48. }
    49.

    4、mapper层

    ①OrderMapper.java

    1. package com.chenchen.ssm.mapper;
    2.  
    3. import com.chenchen.ssm.model.Order;
    4. import com.chenchen.ssm.model.vo.OrderVo;
    5. import org.apache.ibatis.annotations.Param;
    6.  
    7. public interface OrderMapper {
    8.     int deleteByPrimaryKey(Integer orderId);
    9.  
    10.     int insert(Order record);
    11.  
    12.     int insertSelective(Order record);
    13.  
    14.     Order selectByPrimaryKey(Integer orderId);
    15.  
    16.     OrderVo queryOrderVoByOrderId(@Param("orderId") Integer orderId);
    17.  
    18.     int updateByPrimaryKeySelective(Order record);
    19.  
    20.     int updateByPrimaryKey(Order record);
    21. }

    ②OrderMapper.xml

    1. "1.0" encoding="UTF-8" ?>
    2. mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
    3. <mapper namespace="com.chenchen.ssm.mapper.OrderMapper" >
    4.   <resultMap id="BaseResultMap" type="com.chenchen.ssm.model.Order" >
    5.     <constructor >
    6.       <idArg column="order_id" jdbcType="INTEGER" javaType="java.lang.Integer" />
    7.       <arg column="order_no" jdbcType="VARCHAR" javaType="java.lang.String" />
    8.     constructor>
    9.   resultMap>
    10.  
    11.   <resultMap id="OrderVoMap" type="com.chenchen.ssm.model.vo.OrderVo" >
    12.     <result column="order_id" property="orderId">result>
    13.     <result column="order_no" property="orderNo">result>
    14.     <collection property="orderItems" ofType="com.chenchen.ssm.model.OrderItem">
    15.       <result column="order_item_id" property="orderItemId">result>
    16.       <result column="product_id" property="productId">result>
    17.       <result column="quantity" property="quantity">result>
    18.       <result column="oid" property="oid">result>
    19.     collection>
    20.   resultMap>
    21.  
    22.   <sql id="Base_Column_List" >
    23.     order_id, order_no
    24.   sql>
    25.  
    26.   <select id="queryOrderVoByOrderId" resultMap="OrderVoMap" parameterType="java.lang.Integer" >
    27.     select * from t_hibernate_order o,t_hibernate_order_item oi where
    28.     o.order_id=oi.oid and o.order_id=#{orderId}
    29.   select>
    30.  
    31.   <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    32.     select 
    33.     <include refid="Base_Column_List" />
    34.     from t_hibernate_order
    35.     where order_id = #{orderId,jdbcType=INTEGER}
    36.   select>
    37.   <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    38.     delete from t_hibernate_order
    39.     where order_id = #{orderId,jdbcType=INTEGER}
    40.   delete>
    41.   <insert id="insert" parameterType="com.chenchen.ssm.model.Order" >
    42.     insert into t_hibernate_order (order_id, order_no)
    43.     values (#{orderId,jdbcType=INTEGER}, #{orderNo,jdbcType=VARCHAR})
    44.   insert>
    45.   <insert id="insertSelective" parameterType="com.chenchen.ssm.model.Order" >
    46.     insert into t_hibernate_order
    47.     <trim prefix="(" suffix=")" suffixOverrides="," >
    48.       <if test="orderId != null" >
    49.         order_id,
    50.       if>
    51.       <if test="orderNo != null" >
    52.         order_no,
    53.       if>
    54.     trim>
    55.     <trim prefix="values (" suffix=")" suffixOverrides="," >
    56.       <if test="orderId != null" >
    57.         #{orderId,jdbcType=INTEGER},
    58.       if>
    59.       <if test="orderNo != null" >
    60.         #{orderNo,jdbcType=VARCHAR},
    61.       if>
    62.     trim>
    63.   insert>
    64.   <update id="updateByPrimaryKeySelective" parameterType="com.chenchen.ssm.model.Order" >
    65.     update t_hibernate_order
    66.     <set >
    67.       <if test="orderNo != null" >
    68.         order_no = #{orderNo,jdbcType=VARCHAR},
    69.       if>
    70.     set>
    71.     where order_id = #{orderId,jdbcType=INTEGER}
    72.   update>
    73.   <update id="updateByPrimaryKey" parameterType="com.chenchen.ssm.model.Order" >
    74.     update t_hibernate_order
    75.     set order_no = #{orderNo,jdbcType=VARCHAR}
    76.     where order_id = #{orderId,jdbcType=INTEGER}
    77.   update>
    78. mapper>

    ③OrderItemMapper.java

    1. package com.chenchen.ssm.mapper;
    2.  
    3. import com.chenchen.ssm.model.OrderItem;
    4. import com.chenchen.ssm.model.vo.OrderItemVo;
    5. import org.apache.ibatis.annotations.Param;
    6.  
    7. public interface OrderItemMapper {
    8.     int deleteByPrimaryKey(Integer orderItemId);
    9.  
    10.     int insert(OrderItem record);
    11.  
    12.     int insertSelective(OrderItem record);
    13.  
    14.     OrderItem selectByPrimaryKey(Integer orderItemId);
    15.  
    16.     OrderItemVo queryOrderItemVoByOrderItemId(@Param("orderItemId") Integer orderItemId);
    17.  
    18.     int updateByPrimaryKeySelective(OrderItem record);
    19.  
    20.     int updateByPrimaryKey(OrderItem record);
    21. }

    queryByBookId运行效果：

    queryByCid运行效果：

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  • 原文地址：https://blog.csdn.net/m0_67094505/article/details/126363824