• mybatis：关联关系映射

    目录

    一、一对多

    1.1 生成实体类，修改generatorConfig.xml的配置文件 1的这一方

     1.2 分析写SQL语句，然后修改OrderMapper.xml配置

    1.3在对应的实体类中添加新的属性，就和数据库中的数据不对应了，于是建一个vo的包，写一个Vo

    1.4 写OrderMapper

     2.1 多的一方 写SQL语句 配置OrderItemMapper.xml

    2.2 OrderItemMapper

    OrderItemBiz

     二、多对多

    2.1 修改配置文件generatorConfig.xml 逆向生成

    2.2配置映射关系

    2.3三层架构

    一、一对多

    解释：一个老师对应教多个学生班级

    1.1 生成实体类，修改generatorConfig.xml的配置文件 1的这一方

    1. "1.0" encoding="UTF-8" ?>
    2. generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
    3.         "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd" >
    4. <generatorConfiguration>
    5.     
    6.     <properties resource="jdbc.properties"/>
    7.  
    8.     
    9.     <classPathEntry location="E:\\cdl_mvn_repository\\mysql\\mysql-connector-java\\5.1.44\\mysql-connector-java-5.1.44.jar"/>
    10.  
    11.     
    12.     <context id="infoGuardian">
    13.         
    14.         <commentGenerator>
    15.             <property name="suppressAllComments" value="true"/>
    16.             <property name="suppressDate" value="true"/> 
    17.         commentGenerator>
    18.  
    19.         
    20.         <jdbcConnection driverClass="${jdbc.driver}"
    21.                         connectionURL="${jdbc.url}" userId="${jdbc.username}" password="${jdbc.password}"/>
    22.  
    23.         
    24.         <javaTypeResolver>
    25.             
    26.             <property name="forceBigDecimals" value="false"/>
    27.         javaTypeResolver>
    28.  
    29.         
    30.         
    31.         
    32.         <javaModelGenerator targetPackage="com.cdl.model"
    33.                             targetProject="src/main/java">
    34.             
    35.             <property name="enableSubPackages" value="false"/>
    36.             
    37.             <property name="constructorBased" value="true"/>
    38.             
    39.             <property name="trimStrings" value="false"/>
    40.             
    41.             <property name="immutable" value="false"/>
    42.         javaModelGenerator>
    43.  
    44.         
    45.         <sqlMapGenerator targetPackage="com.cdl.mapper"
    46.                          targetProject="src/main/java">
    47.             
    48.             <property name="enableSubPackages" value="false"/>
    49.         sqlMapGenerator>
    50.  
    51.         
    52.         
    53.         
    54.         
    55.         <javaClientGenerator targetPackage="com.cdl.mapper"
    56.                              targetProject="src/main/java" type="XMLMAPPER">
    57.             
    58.             <property name="enableSubPackages" value="false"/>
    59.         javaClientGenerator>
    60.  
    61.         
    62.         
    63.         
    64.         
    65.         
    66.         
    67.         
    68.         
    69.         
    70.         
    71.         
    72.         
    73.         
    74.  
    75.  
    76.         <table schema="" tableName="t_hibernate_order" domainObjectName="Order"
    77.                enableCountByExample="false" enableDeleteByExample="false"
    78.                enableSelectByExample="false" enableUpdateByExample="false">
    79.         table>
    80.  
    81.  
    82.         <table schema="" tableName="t_hibernate_order_item" domainObjectName="OrderItem"
    83.                enableCountByExample="false" enableDeleteByExample="false"
    84.                enableSelectByExample="false" enableUpdateByExample="false">
    85.         table>
    86.  
    87.     context>
    88. generatorConfiguration>

    逆向生成实体类和方法等

     

     可见图：已生成成功

     1.2 分析写SQL语句，然后修改OrderMapper.xml配置

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

    1.3在对应的实体类中添加新的属性，就和数据库中的数据不对应了，于是建一个vo的包，写一个Vo

    OrderVo

    1. package com.cdl.ssm.model.vo;
    2.  
    3. import com.cdl.ssm.model.Order;
    4. import com.cdl.ssm.model.OrderItem;
    5.  
    6. import java.util.List;
    7.  
    8. /**
    9.  * @author cdl
    10.  * @site www.cdl.com
    11.  * @create 2022-08-16 9:38
    12.  *
    13.  * vo不仅包含当前表的信息 还能够包含关联表的信息
    14.  *
    15.  * 当前订单会有一个或者多个订单项 多个订单项必须用集合进行接收
    16.  */
    17. public class OrderVo  extends Order {
    18.     //通过订单号查询本次订单的详细信息及对应的所属订单项信息
    19.     private List orderItems;
    20.  
    21.     public List getOrderItems() {
    22.         return orderItems;
    23.     }
    24.  
    25.     public void setOrderItems(List orderItems) {
    26.         this.orderItems = orderItems;
    27.     }
    28. }
    29.

     OrderVo  

    1. package com.cdl.ssm.model.vo;
    2.  
    3. import com.cdl.ssm.model.Order;
    4. import com.cdl.ssm.model.OrderItem;
    5.  
    6. import java.util.List;
    7.  
    8. /**
    9.  * @author cdl
    10.  * @site www.cdl.com
    11.  * @create 2022-08-16 9:38
    12.  *
    13.  * vo不仅包含当前表的信息 还能够包含关联表的信息
    14.  *
    15.  * 当前订单会有一个或者多个订单项 多个订单项必须用集合进行接收
    16.  */
    17. public class OrderVo  extends Order {
    18.     //通过订单号查询本次订单的详细信息及对应的所属订单项信息
    19.     private List orderItems;
    20.  
    21.     public List getOrderItems() {
    22.         return orderItems;
    23.     }
    24.  
    25.     public void setOrderItems(List orderItems) {
    26.         this.orderItems = orderItems;
    27.     }
    28. }

    1.4 写OrderMapper

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

    1. package com.cdl.biz;
    2.  
    3. import com.cdl.ssm.model.Order;
    4.  
    5. public interface OrderBiz {
    6.     int deleteByPrimaryKey(Integer orderId);
    7.  
    8.     int insert(Order record);
    9.  
    10.     int insertSelective(Order record);
    11.  
    12.     Order selectByPrimaryKey(Integer orderId);
    13.  
    14.     OrderVo queryOrderVoByOrderId( Integer orderId);
    15.  
    16.     int updateByPrimaryKeySelective(Order record);
    17.  
    18.     int updateByPrimaryKey(Order record);
    19. }

    对应的实现类：

    1. package com.cdl.biz.impl;
    2.  
    3. import com.cdl.biz.OrderBiz;
    4. import com.cdl.ssm.mapper.OrderMapper;
    5. import com.cdl.ssm.model.Order;
    6. import org.springframework.beans.factory.annotation.Autowired;
    7. import org.springframework.stereotype.Service;
    8.  
    9. /**
    10.  * @author cdl
    11.  * @site www.cdl.com
    12.  * @create 2022-08-16 10:31
    13.  */
    14. @Service
    15. public class OrderBizImpl implements OrderBiz {
    16.  
    17.     @Autowired
    18.     private OrderMapper orderMapper;
    19.  
    20.  
    21.     @Override
    22.     public int deleteByPrimaryKey(Integer orderId) {
    23.         return 0;
    24.     }
    25.  
    26.     @Override
    27.     public int insert(Order record) {
    28.         return 0;
    29.     }
    30.  
    31.     @Override
    32.     public int insertSelective(Order record) {
    33.         return 0;
    34.     }
    35.  
    36.     @Override
    37.     public Order selectByPrimaryKey(Integer orderId) {
    38.         return null;
    39.     }
    40.  
    41.     @Override
    42.     public OrderVo queryOrderVoByOrderId(Integer orderId) {
    43.         return orderMapper.queryOrderVoByOrderId(orderId);
    44.     }
    45.  
    46.     @Override
    47.     public int updateByPrimaryKeySelective(Order record) {
    48.         return 0;
    49.     }
    50.  
    51.     @Override
    52.     public int updateByPrimaryKey(Order record) {
    53.         return 0;
    54.     }
    55. }

    测试方法：OrderBizImplTest 

    1. package com.cdl.biz.impl;
    2.  
    3. import com.cdl.biz.OrderBiz;
    4. import com.cdl.ssm.model.Order;
    5. import org.junit.Test;
    6. import org.junit.runner.RunWith;
    7. import org.springframework.beans.factory.annotation.Autowired;
    8. import org.springframework.test.context.ContextConfiguration;
    9. import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    10.  
    11. import static org.junit.Assert.*;
    12.  
    13. /**
    14.  * @author cdl
    15.  * @site www.cdl.com
    16.  * @create 2022-08-16 10:37
    17.  */
    18. @RunWith(SpringJUnit4ClassRunner.class)
    19. @ContextConfiguration(locations ={"classpath:applicationContext-mybatis.xml"})
    20. public class OrderBizImplTest {
    21.  
    22.     @Autowired
    23.     private OrderBiz orderBiz ;
    24.  
    25.     @Test
    26.     public void queryOrderVoByOrderId() {
    27.         OrderVo orderVO = orderBiz.queryOrderVoByOrderId(9);
    28.         System.out.println(orderVo);
    29.     }
    30. }

     @Data:相当于生成了set/get/toString方法

    @NoArgsConstructor 无参构造器
@AllArgsConstructor 有参构造器

    前提是加载了lombok依赖

     2.1 多的一方 写SQL语句 配置OrderItemMapper.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.cdl.ssm.mapper.OrderItemMapper" >
    4.   <resultMap id="BaseResultMap" type="com.cdl.ssm.model.OrderItem" >
    5.     <constructor >
    6.       <idArg column="order_item_id" jdbcType="INTEGER" javaType="java.lang.Integer" />
    7.       <arg column="product_id" jdbcType="INTEGER" javaType="java.lang.Integer" />
    8.       <arg column="quantity" jdbcType="INTEGER" javaType="java.lang.Integer" />
    9.       <arg column="oid" jdbcType="INTEGER" javaType="java.lang.Integer" />
    10.     constructor>
    11.   resultMap>
    12.   <sql id="Base_Column_List" >
    13.     order_item_id, product_id, quantity, oid
    14.   sql>
    15.  
    16.   <resultMap id="OrderItemVoMap" type="com.cdl.ssm.model.vo.OrderItemVo" >
    17.     <result column="order_item_id" property="orderItemId" >result>
    18.     <result column="product_id" property="productId" >result>
    19.     <result column="quantity" property="quantity" >result>
    20.     <result column="oid" property="oid" >result>
    21.     <association property="order" javaType="com.cdl.ssm.model.Order">
    22.       <result column="order_id" property="orderId" >result>
    23.       <result column="order_no" property="orderNo" >result>
    24.     association>
    25.   resultMap>
    26.  
    27.  
    28.  
    29.   <select id="queryOrderItemVoByOrderItemId" resultMap="OrderItemVoMap" parameterType="java.lang.Integer" >
    30.          select * from t_hibernate_order o,t_hibernate_order_item oi where o.order_id = oi.oid and oi.order_item_id = #{orderItemId}
    31.   select>
    32.  
    33.  
    34.  
    35.   <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    36.     select 
    37.     <include refid="Base_Column_List" />
    38.     from t_hibernate_order_item
    39.     where order_item_id = #{orderItemId,jdbcType=INTEGER}
    40.   select>
    41.   <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    42.     delete from t_hibernate_order_item
    43.     where order_item_id = #{orderItemId,jdbcType=INTEGER}
    44.   delete>
    45.   <insert id="insert" parameterType="com.cdl.ssm.model.OrderItem" >
    46.     insert into t_hibernate_order_item (order_item_id, product_id, quantity, 
    47.       oid)
    48.     values (#{orderItemId,jdbcType=INTEGER}, #{productId,jdbcType=INTEGER}, #{quantity,jdbcType=INTEGER}, 
    49.       #{oid,jdbcType=INTEGER})
    50.   insert>
    51.   <insert id="insertSelective" parameterType="com.cdl.ssm.model.OrderItem" >
    52.     insert into t_hibernate_order_item
    53.     <trim prefix="(" suffix=")" suffixOverrides="," >
    54.       <if test="orderItemId != null" >
    55.         order_item_id,
    56.       if>
    57.       <if test="productId != null" >
    58.         product_id,
    59.       if>
    60.       <if test="quantity != null" >
    61.         quantity,
    62.       if>
    63.       <if test="oid != null" >
    64.         oid,
    65.       if>
    66.     trim>
    67.     <trim prefix="values (" suffix=")" suffixOverrides="," >
    68.       <if test="orderItemId != null" >
    69.         #{orderItemId,jdbcType=INTEGER},
    70.       if>
    71.       <if test="productId != null" >
    72.         #{productId,jdbcType=INTEGER},
    73.       if>
    74.       <if test="quantity != null" >
    75.         #{quantity,jdbcType=INTEGER},
    76.       if>
    77.       <if test="oid != null" >
    78.         #{oid,jdbcType=INTEGER},
    79.       if>
    80.     trim>
    81.   insert>
    82.   <update id="updateByPrimaryKeySelective" parameterType="com.cdl.ssm.model.OrderItem" >
    83.     update t_hibernate_order_item
    84.     <set >
    85.       <if test="productId != null" >
    86.         product_id = #{productId,jdbcType=INTEGER},
    87.       if>
    88.       <if test="quantity != null" >
    89.         quantity = #{quantity,jdbcType=INTEGER},
    90.       if>
    91.       <if test="oid != null" >
    92.         oid = #{oid,jdbcType=INTEGER},
    93.       if>
    94.     set>
    95.     where order_item_id = #{orderItemId,jdbcType=INTEGER}
    96.   update>
    97.   <update id="updateByPrimaryKey" parameterType="com.cdl.ssm.model.OrderItem" >
    98.     update t_hibernate_order_item
    99.     set product_id = #{productId,jdbcType=INTEGER},
    100.       quantity = #{quantity,jdbcType=INTEGER},
    101.       oid = #{oid,jdbcType=INTEGER}
    102.     where order_item_id = #{orderItemId,jdbcType=INTEGER}
    103.   update>
    104. mapper>

    2.2 OrderItemMapper

    1. package com.cdl.ssm.mapper;
    2.  
    3. import com.cdl.ssm.model.OrderItem;
    4. import com.cdl.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. }

    OrderItemBiz

    1. package com.cdl.biz;
    2.  
    3. import com.cdl.ssm.model.OrderItem;
    4. import com.cdl.ssm.model.vo.OrderItemVo;
    5.  
    6. public interface OrderItemBiz {
    7.     int deleteByPrimaryKey(Integer orderItemId);
    8.  
    9.     int insert(OrderItem record);
    10.  
    11.     int insertSelective(OrderItem record);
    12.  
    13.     OrderItem selectByPrimaryKey(Integer orderItemId);
    14.  
    15.     OrderItemVo queryOrderItemVoByOrderItemId(Integer orderItemId);
    16.  
    17.     int updateByPrimaryKeySelective(OrderItem record);
    18.  
    19.     int updateByPrimaryKey(OrderItem record);
    20. }

     OrderItemBizImpl 

    1. package com.cdl.biz.impl;
    2.  
    3. import com.cdl.biz.OrderItemBiz;
    4. import com.cdl.ssm.mapper.OrderItemMapper;
    5. import com.cdl.ssm.model.OrderItem;
    6. import com.cdl.ssm.model.vo.OrderItemVo;
    7. import org.springframework.beans.factory.annotation.Autowired;
    8. import org.springframework.stereotype.Service;
    9.  
    10. /**
    11.  * @author cdl
    12.  * @site www.cdl.com
    13.  * @create 2022-08-16 11:37
    14.  */
    15. @Service
    16. public class OrderItemBizImpl implements OrderItemBiz {
    17.  
    18.     @Autowired
    19.     private OrderItemMapper orderItemMapper;
    20.     @Override
    21.     public int deleteByPrimaryKey(Integer orderItemId) {
    22.         return 0;
    23.     }
    24.  
    25.     @Override
    26.     public int insert(OrderItem record) {
    27.         return 0;
    28.     }
    29.  
    30.     @Override
    31.     public int insertSelective(OrderItem record) {
    32.         return 0;
    33.     }
    34.  
    35.     @Override
    36.     public OrderItem selectByPrimaryKey(Integer orderItemId) {
    37.         return null;
    38.     }
    39.  
    40.     @Override
    41.     public OrderItemVo queryOrderItemVoByOrderItemId(Integer orderItemId) {
    42.         return orderItemMapper.queryOrderItemVoByOrderItemId(orderItemId);
    43.     }
    44.  
    45.     @Override
    46.     public int updateByPrimaryKeySelective(OrderItem record) {
    47.         return 0;
    48.     }
    49.  
    50.     @Override
    51.     public int updateByPrimaryKey(OrderItem record) {
    52.         return 0;
    53.     }
    54. }

     OrderItemBizImplTest 

    1. package com.cdl.biz.impl;
    2.  
    3. import com.cdl.biz.OrderItemBiz;
    4. import com.cdl.ssm.model.vo.OrderItemVo;
    5. import org.junit.Test;
    6. import org.junit.runner.RunWith;
    7. import org.springframework.beans.factory.annotation.Autowired;
    8. import org.springframework.test.context.ContextConfiguration;
    9. import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    10.  
    11. /**
    12.  * @author cdl
    13.  * @site www.cdl.com
    14.  * @create 2022-08-16 11:45
    15.  */
    16. @RunWith(SpringJUnit4ClassRunner.class)
    17. @ContextConfiguration(locations ={"classpath:applicationContext-mybatis.xml"})
    18. public class OrderItemBizImplTest {
    19.  
    20.     @Autowired
    21.     private OrderItemBiz orderItemBiz;
    22.     @Test
    23.     public void queryOrderItemVoByOrderItemId() {
    24.         OrderItemVo orderItemVo = orderItemBiz.queryOrderItemVoByOrderItemId(33);
    25.         System.out.println(orderItemVo);
    26.     }
    27. }

     二、多对多

    2.1 修改配置文件generatorConfig.xml 逆向生成

    1. "1.0" encoding="UTF-8" ?>
    2. generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
    3.         "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd" >
    4. <generatorConfiguration>
    5.     
    6.     <properties resource="jdbc.properties"/>
    7.  
    8.     
    9.     <classPathEntry location="E:\\cdl_mvn_repository\\mysql\\mysql-connector-java\\5.1.44\\mysql-connector-java-5.1.44.jar"/>
    10.  
    11.     
    12.     <context id="infoGuardian">
    13.         
    14.         <commentGenerator>
    15.             <property name="suppressAllComments" value="true"/>
    16.             <property name="suppressDate" value="true"/> 
    17.         commentGenerator>
    18.  
    19.         
    20.         <jdbcConnection driverClass="${jdbc.driver}"
    21.                         connectionURL="${jdbc.url}" userId="${jdbc.username}" password="${jdbc.password}"/>
    22.  
    23.         
    24.         <javaTypeResolver>
    25.             
    26.             <property name="forceBigDecimals" value="false"/>
    27.         javaTypeResolver>
    28.  
    29.         
    30.         
    31.         
    32.         <javaModelGenerator targetPackage="com.cdl.ssm.model"
    33.                             targetProject="src/main/java">
    34.             
    35.             <property name="enableSubPackages" value="false"/>
    36.             
    37.             <property name="constructorBased" value="true"/>
    38.             
    39.             <property name="trimStrings" value="false"/>
    40.             
    41.             <property name="immutable" value="false"/>
    42.         javaModelGenerator>
    43.  
    44.         
    45.         <sqlMapGenerator targetPackage="com.cdl.ssm.mapper"
    46.                          targetProject="src/main/java">
    47.             
    48.             <property name="enableSubPackages" value="false"/>
    49.         sqlMapGenerator>
    50.  
    51.         
    52.         
    53.         
    54.         
    55.         <javaClientGenerator targetPackage="com.cdl.ssm.mapper"
    56.                              targetProject="src/main/java" type="XMLMAPPER">
    57.             
    58.             <property name="enableSubPackages" value="false"/>
    59.         javaClientGenerator>
    60.  
    61.         
    62.         
    63.         
    64.         
    65.         
    66.         
    67.         
    68.         
    69.         
    70.         
    71.         
    72.         
    73.         
    74.  
    75.  
    76.         <table schema="" tableName="t_hibernate_Book" domainObjectName="Hbook"
    77.                enableCountByExample="false" enableDeleteByExample="false"
    78.                enableSelectByExample="false" enableUpdateByExample="false">
    79.         table>
    80.  
    81.  
    82.         <table schema="" tableName="t_hibernate_category" domainObjectName="Category"
    83.                enableCountByExample="false" enableDeleteByExample="false"
    84.                enableSelectByExample="false" enableUpdateByExample="false">
    85.         table>
    86.  
    87.         <table schema="" tableName="t_hibernate_book_category" domainObjectName="HbookCategory"
    88.                enableCountByExample="false" enableDeleteByExample="false"
    89.                enableSelectByExample="false" enableUpdateByExample="false">
    90.         table>
    91.  
    92.     context>
    93. generatorConfiguration>

    写vo类 HbookVo  

    1. package com.cdl.ssm.model.vo;
    2.  
    3. import com.cdl.ssm.model.Category;
    4. import com.cdl.ssm.model.Hbook;
    5.  
    6. import java.util.List;
    7.  
    8. /**
    9.  * @author cdl
    10.  * @site www.cdl.com
    11.  * @create 2022-08-16 12:42
    12.  */
    13. public class HbookVo  extends Hbook {
    14.  
    15.     private List categories;
    16.  
    17.     public List getCategories() {
    18.         return categories;
    19.     }
    20.  
    21.     public void setCategories(List categories) {
    22.         this.categories = categories;
    23.     }
    24. }

     CategoryVo  

    1. package com.cdl.ssm.model.vo;
    2.  
    3. import com.cdl.ssm.model.Category;
    4. import com.cdl.ssm.model.Hbook;
    5.  
    6. import java.util.List;
    7.  
    8. /**
    9.  * @author cdl
    10.  * @site www.cdl.com
    11.  * @create 2022-08-16 12:43
    12.  */
    13. public class CategoryVo  extends Category {
    14.     private List  hbooks;
    15.  
    16.     public List getHbooks() {
    17.         return hbooks;
    18.     }
    19.  
    20.     public void setHbooks(List hbooks) {
    21.         this.hbooks = hbooks;
    22.     }
    23. }

    2.2配置映射关系

    HbookCategoryMapper.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.cdl.ssm.mapper.HbookCategoryMapper" >
    4.   <resultMap id="BaseResultMap" type="com.cdl.ssm.model.HbookCategory" >
    5.     <constructor >
    6.       <idArg column="bcid" jdbcType="INTEGER" javaType="java.lang.Integer" />
    7.       <arg column="bid" jdbcType="INTEGER" javaType="java.lang.Integer" />
    8.       <arg column="cid" jdbcType="INTEGER" javaType="java.lang.Integer" />
    9.     constructor>
    10.   resultMap>
    11.   <sql id="Base_Column_List" >
    12.     bcid, bid, cid
    13.   sql>
    14.  
    15.   <resultMap id="HbookVoMap" type="com.cdl.ssm.model.vo.HbookVo">
    16.     <result property="bookId" column="book_id">result>
    17.     <result property="bookName" column="book_name">result>
    18.     <collection property="categories" ofType="com.cdl.ssm.model.Category">
    19.       <result property="categoryId" column="category_id">result>
    20.       <result property="categoryName" column="category_name">result>
    21.     collection>
    22.   resultMap>
    23.  
    24.   <resultMap id="CategoryVoMap" type="com.cdl.ssm.model.vo.CategoryVo">
    25.     <result property="categoryId" column="category_id">result>
    26.     <result property="categoryName" column="category_name">result>
    27.     <collection property="hbooks" ofType="com.cdl.ssm.model.Hbook">
    28.       <result property="bookId" column="book_id">result>
    29.       <result property="bookName" column="book_name">result>
    30.     collection>
    31.   resultMap>
    32.  
    33.   <select id="queryByBookId" resultMap="HbookVoMap" parameterType="java.lang.Integer">
    34. select * from t_hibernate_book b,t_hibernate_book_category bc,t_hibernate_category c
    35.      where b.book_id = bc.bid and bc.cid = c.category_id and b.book_id = #{bookId}
    36.  select>
    37.   <select id="queryByCid" resultMap="CategoryVoMap" parameterType="java.lang.Integer">
    38. select * from t_hibernate_book b,t_hibernate_book_category bc,t_hibernate_category c
    39.      where b.book_id = bc.bid and bc.cid = c.category_id and c.category_id=#{cid}
    40.    select>
    41.  
    42.  
    43.  
    44.   <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    45.     select 
    46.     <include refid="Base_Column_List" />
    47.     from t_hibernate_book_category
    48.     where bcid = #{bcid,jdbcType=INTEGER}
    49.   select>
    50.   <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    51.     delete from t_hibernate_book_category
    52.     where bcid = #{bcid,jdbcType=INTEGER}
    53.   delete>
    54.   <insert id="insert" parameterType="com.cdl.ssm.model.HbookCategory" >
    55.     insert into t_hibernate_book_category (bcid, bid, cid
    56.       )
    57.     values (#{bcid,jdbcType=INTEGER}, #{bid,jdbcType=INTEGER}, #{cid,jdbcType=INTEGER}
    58.       )
    59.   insert>
    60.   <insert id="insertSelective" parameterType="com.cdl.ssm.model.HbookCategory" >
    61.     insert into t_hibernate_book_category
    62.     <trim prefix="(" suffix=")" suffixOverrides="," >
    63.       <if test="bcid != null" >
    64.         bcid,
    65.       if>
    66.       <if test="bid != null" >
    67.         bid,
    68.       if>
    69.       <if test="cid != null" >
    70.         cid,
    71.       if>
    72.     trim>
    73.     <trim prefix="values (" suffix=")" suffixOverrides="," >
    74.       <if test="bcid != null" >
    75.         #{bcid,jdbcType=INTEGER},
    76.       if>
    77.       <if test="bid != null" >
    78.         #{bid,jdbcType=INTEGER},
    79.       if>
    80.       <if test="cid != null" >
    81.         #{cid,jdbcType=INTEGER},
    82.       if>
    83.     trim>
    84.   insert>
    85.   <update id="updateByPrimaryKeySelective" parameterType="com.cdl.ssm.model.HbookCategory" >
    86.     update t_hibernate_book_category
    87.     <set >
    88.       <if test="bid != null" >
    89.         bid = #{bid,jdbcType=INTEGER},
    90.       if>
    91.       <if test="cid != null" >
    92.         cid = #{cid,jdbcType=INTEGER},
    93.       if>
    94.     set>
    95.     where bcid = #{bcid,jdbcType=INTEGER}
    96.   update>
    97.   <update id="updateByPrimaryKey" parameterType="com.cdl.ssm.model.HbookCategory" >
    98.     update t_hibernate_book_category
    99.     set bid = #{bid,jdbcType=INTEGER},
    100.       cid = #{cid,jdbcType=INTEGER}
    101.     where bcid = #{bcid,jdbcType=INTEGER}
    102.   update>
    103. mapper>

    2.3三层架构

    HbookCategoryMapper

    1. package com.cdl.ssm.mapper;
    2.  
    3. import com.cdl.ssm.model.HbookCategory;
    4. import com.cdl.ssm.model.vo.CategoryVo;
    5. import com.cdl.ssm.model.vo.HbookVo;
    6. import org.apache.ibatis.annotations.Param;
    7.  
    8. public interface HbookCategoryMapper {
    9.     int deleteByPrimaryKey(Integer bcid);
    10.  
    11.     int insert(HbookCategory record);
    12.  
    13.     int insertSelective(HbookCategory record);
    14.  
    15.     HbookCategory selectByPrimaryKey(Integer bcid);
    16.  
    17.     int updateByPrimaryKeySelective(HbookCategory record);
    18.  
    19.     int updateByPrimaryKey(HbookCategory record);
    20.  
    21.     HbookVo queryByBookId(@Param("bookId") Integer bookId);
    22.  
    23.     CategoryVo queryByCid(@Param("cid") Integer cid);
    24.  
    25.  
    26. }

     HbookCategoryBiz 

    1. package com.cdl.biz;
    2.  
    3. import com.cdl.ssm.model.HbookCategory;
    4. import com.cdl.ssm.model.vo.CategoryVo;
    5. import com.cdl.ssm.model.vo.HbookVo;
    6.  
    7. public interface HbookCategoryBiz {
    8.     int deleteByPrimaryKey(Integer bcid);
    9.  
    10.     int insert(HbookCategory record);
    11.  
    12.     int insertSelective(HbookCategory record);
    13.  
    14.     HbookCategory selectByPrimaryKey(Integer bcid);
    15.  
    16.     int updateByPrimaryKeySelective(HbookCategory record);
    17.  
    18.     int updateByPrimaryKey(HbookCategory record);
    19.  
    20.     HbookVo queryByBookId(Integer bookId);
    21.  
    22.     CategoryVo queryByCid(Integer cid);
    23.  
    24.  
    25. }

     HbookCategoryBizImpl 

    1. package com.cdl.biz.impl;
    2.  
    3. import com.cdl.biz.HbookCategoryBiz;
    4. import com.cdl.ssm.mapper.HbookCategoryMapper;
    5. import com.cdl.ssm.model.HbookCategory;
    6. import com.cdl.ssm.model.vo.CategoryVo;
    7. import com.cdl.ssm.model.vo.HbookVo;
    8. import org.springframework.beans.factory.annotation.Autowired;
    9. import org.springframework.stereotype.Service;
    10.  
    11. /**
    12.  * @author cdl
    13.  * @site www.cdl.com
    14.  * @create 2022-08-16 12:55
    15.  */
    16. @Service
    17. public class HbookCategoryBizImpl implements HbookCategoryBiz {
    18.  
    19.     @Autowired
    20.     private HbookCategoryMapper hbookCategoryMapper;
    21.  
    22.     @Override
    23.     public int deleteByPrimaryKey(Integer bcid) {
    24.         return 0;
    25.     }
    26.  
    27.     @Override
    28.     public int insert(HbookCategory record) {
    29.         return 0;
    30.     }
    31.  
    32.     @Override
    33.     public int insertSelective(HbookCategory record) {
    34.         return 0;
    35.     }
    36.  
    37.     @Override
    38.     public HbookCategory selectByPrimaryKey(Integer bcid) {
    39.         return null;
    40.     }
    41.  
    42.     @Override
    43.     public int updateByPrimaryKeySelective(HbookCategory record) {
    44.         return 0;
    45.     }
    46.  
    47.     @Override
    48.     public int updateByPrimaryKey(HbookCategory record) {
    49.         return 0;
    50.     }
    51.  
    52.     @Override
    53.     public HbookVo queryByBookId(Integer bookId) {
    54.         return hbookCategoryMapper.queryByBookId(bookId);
    55.     }
    56.  
    57.     @Override
    58.     public CategoryVo queryByCid(Integer cid) {
    59.         return hbookCategoryMapper.queryByCid(cid);
    60.     }
    61. }

     HbookCategoryBizImplTest 

    1. package com.cdl.biz.impl;
    2.  
    3. import com.cdl.biz.HbookCategoryBiz;
    4. import com.cdl.ssm.model.vo.CategoryVo;
    5. import com.cdl.ssm.model.vo.HbookVo;
    6. import org.junit.Test;
    7. import org.junit.runner.RunWith;
    8. import org.springframework.beans.factory.annotation.Autowired;
    9. import org.springframework.test.context.ContextConfiguration;
    10. import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    11.  
    12. /**
    13.  * @author cdl
    14.  * @site www.cdl.com
    15.  * @create 2022-08-16 12:57
    16.  */
    17. @RunWith(SpringJUnit4ClassRunner.class)
    18. @ContextConfiguration(locations ={"classpath:applicationContext-mybatis.xml"})
    19. public class HbookCategoryBizImplTest {
    20.  
    21.     @Autowired
    22.     private HbookCategoryBiz hbookCategoryBiz;
    23.  
    24.     @Test
    25.     public void queryByBookId() {
    26.         HbookVo hbookVo = hbookCategoryBiz.queryByBookId(8);
    27.         System.out.println(hbookVo);
    28.         hbookVo.getCategories().forEach(System.out::println);
    29.     }
    30.  
    31.     @Test
    32.     public void queryByCid() {
    33.         CategoryVo categoryVo = hbookCategoryBiz.queryByCid(8);
    34.         System.out.println(categoryVo);
    35.         categoryVo.getHbooks().forEach(System.out::println);
    36.     }
    37. }

     

     

  • 相关阅读:
    Windows环境下安装MongoDB数据库
    MySQL查询优化之order by 与 group by优化
    【store商城项目03】修改密码的开发
    react-redux使用
    2、kubeadm安装单master集群
    基本数据类型----Python入门之玩转列表
    win11右键改回win10风格方法
    北美干旱监测 (NADM)数据集
    内部类_Java
    jQuery
  • 原文地址：https://blog.csdn.net/weixin_62735525/article/details/126353977