• 04、关联关系映射

    目录

    一、一对多

    二、多对多

    一、一对多

    概念：比如一个老师对应多个班

     步骤：

    ①修改generatorConfig.xml，然后逆向生成

    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:\\Maven\\mvn_baoc\\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.mgy.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.mgy.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.mgy.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.  
    77.         <table schema="" tableName="t_hibernate_order" domainObjectName="Oreder"
    78.                enableCountByExample="false" enableDeleteByExample="false"
    79.                enableSelectByExample="false" enableUpdateByExample="false">
    80.         table>
    81.  
    82.         <table schema="" tableName="t_hibernate_order_item" domainObjectName="OrederItem"
    83.                enableCountByExample="false" enableDeleteByExample="false"
    84.                enableSelectByExample="false" enableUpdateByExample="false">
    85.         table>
    86.  
    87.  
    88.     context>
    89. generatorConfiguration>

     

    ②、 创建两个类

    OrderVo：

    1. package com.mgy.ssm.model.vo;
    2.  
    3. import com.mgy.ssm.model.Oreder;
    4. import com.mgy.ssm.model.OrederItem;
    5.  
    6. import java.util.List;
    7.  
    8. /**
    9.  * @author 云鹤衫
    10.  * @site www.yunheshan.com
    11.  * @company xxx公司
    12.  * @create  2022-08-15 23:10
    13.  *
    14.  * vo类不仅仅包含当前表的信息，还能包含相关联表的信息
    15.  *
    16.  * 当前订单会有一个或者多个订单项，多个订单项必须集合进行接受
    17.  */
    18. public class OrderVo extends Oreder{
    19. //    通过订单号查询本次订单的详细信息及对应的所有订单项信息
    20.     private List orederItems;
    21.  
    22.     public List getOrederItems() {
    23.         return orederItems;
    24.     }
    25.  
    26.     public void setOrederItems(List orederItems) {
    27.         this.orederItems = orederItems;
    28.     }
    29. }

     OrderItemVo类：

    1. package com.mgy.ssm.model.vo;
    2.  
    3. import com.mgy.ssm.model.Oreder;
    4. import com.mgy.ssm.model.OrederItem;
    5.  
    6. /**
    7.  * @author 云鹤衫
    8.  * @site www.yunheshan.com
    9.  * @company xxx公司
    10.  * @create  2022-08-15 23:14
    11.  * 某一个订单项一定属于某个订单的
    12.  */
    13. public class OrederItemVo extends OrederItem {
    14.     private Oreder oreder;
    15.  
    16.     public Oreder getOreder() {
    17.         return oreder;
    18.     }
    19.  
    20.     public void setOreder(Oreder oreder) {
    21.         this.oreder = oreder;
    22.     }
    23. }

     ③、修改OrderMapper.xml

    2. mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
    3. <mapper namespace="com.mgy.ssm.mapper.OrederMapper" >
    4.   <resultMap id="BaseResultMap" type="com.mgy.ssm.model.Oreder" >
    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.mgy.ssm.model.vo.OrderVo" >
    12.     <result column="order_id" property="orderId">result>
    13.     <result column="order_no" property="orderNo">result>
    14.     <collection property="orederItems" ofType="com.mgy.ssm.model.OrederItem">
    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.  
    20.     collection>
    21.  
    22.   resultMap>
    23.  
    24.   <sql id="Base_Column_List" >
    25.     order_id, order_no
    26.   sql>
    27.   <select id="queryOrderVoByOrderId" resultMap="OrderVoMap" parameterType="java.lang.Integer" >
    28.     select 
    29.     <include refid="Base_Column_List" />
    30.     from t_hibernate_order
    31.     where order_id = #{orderId,jdbcType=INTEGER}
    32.   select>
    33.  
    34.  
    35.   <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    36.         select * from t_hibernate_order o,t_hibernate_order_item oi
    37.         where o.order_id = oi.oid and o.order_id =#{orderId}
    38.   select>
    39.  
    40.  
    41.  
    42.   <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    43.     delete from t_hibernate_order
    44.     where order_id = #{orderId,jdbcType=INTEGER}
    45.   delete>
    46.   <insert id="insert" parameterType="com.mgy.ssm.model.Oreder" >
    47.     insert into t_hibernate_order (order_id, order_no)
    48.     values (#{orderId,jdbcType=INTEGER}, #{orderNo,jdbcType=VARCHAR})
    49.   insert>
    50.   <insert id="insertSelective" parameterType="com.mgy.ssm.model.Oreder" >
    51.     insert into t_hibernate_order
    52.     <trim prefix="(" suffix=")" suffixOverrides="," >
    53.       <if test="orderId != null" >
    54.         order_id,
    55.       if>
    56.       <if test="orderNo != null" >
    57.         order_no,
    58.       if>
    59.     trim>
    60.     <trim prefix="values (" suffix=")" suffixOverrides="," >
    61.       <if test="orderId != null" >
    62.         #{orderId,jdbcType=INTEGER},
    63.       if>
    64.       <if test="orderNo != null" >
    65.         #{orderNo,jdbcType=VARCHAR},
    66.       if>
    67.     trim>
    68.   insert>
    69.   <update id="updateByPrimaryKeySelective" parameterType="com.mgy.ssm.model.Oreder" >
    70.     update t_hibernate_order
    71.     <set >
    72.       <if test="orderNo != null" >
    73.         order_no = #{orderNo,jdbcType=VARCHAR},
    74.       if>
    75.     set>
    76.     where order_id = #{orderId,jdbcType=INTEGER}
    77.   update>
    78.   <update id="updateByPrimaryKey" parameterType="com.mgy.ssm.model.Oreder" >
    79.     update t_hibernate_order
    80.     set order_no = #{orderNo,jdbcType=VARCHAR}
    81.     where order_id = #{orderId,jdbcType=INTEGER}
    82.   update>
    83. mapper>

     再将以下方法加入到OrederMapper

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

     创建OrederBiz接口

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

     实现类：

    1. package com.mgy.ssm.biz.impl;
    2.  
    3. import com.mgy.ssm.biz.OredeBiz;
    4. import com.mgy.ssm.mapper.OrederMapper;
    5. import com.mgy.ssm.model.Oreder;
    6. import com.mgy.ssm.model.vo.OrderVo;
    7. import org.springframework.beans.factory.annotation.Autowired;
    8. import org.springframework.stereotype.Service;
    9.  
    10. /**
    11.  * @author 云鹤衫
    12.  * @site www.yunheshan.com
    13.  * @company xxx公司
    14.  * @create  2022-08-15 23:31
    15.  */
    16. @Service
    17. public class OredeBizImpl implements OredeBiz {
    18.     @Autowired
    19.     private OrederMapper orederMapper;
    20.     @Override
    21.     public int deleteByPrimaryKey(Integer orderId) {
    22.         return 0;
    23.     }
    24.  
    25.     @Override
    26.     public int insert(Oreder record) {
    27.         return 0;
    28.     }
    29.  
    30.     @Override
    31.     public int insertSelective(Oreder record) {
    32.         return 0;
    33.     }
    34.  
    35.     @Override
    36.     public Oreder selectByPrimaryKey(Integer orderId) {
    37.         return null;
    38.     }
    39.  
    40.     @Override
    41.     public OrderVo queryOrderVoByOrderId(Integer orderId) {
    42.         return orederMapper.queryOrderVoByOrderId(orderId);
    43.     }
    44.  
    45.  
    46.     @Override
    47.     public int updateByPrimaryKeySelective(Oreder record) {
    48.         return 0;
    49.     }
    50.  
    51.     @Override
    52.     public int updateByPrimaryKey(Oreder record) {
    53.         return 0;
    54.     }
    55. }
    56.

     测试类：

    1. package com.mgy.ssm.biz.impl;
    2.  
    3.  
    4. import com.mgy.ssm.biz.OredeBiz;
    5. import com.mgy.ssm.model.Oreder;
    6. import com.mgy.ssm.model.vo.OrderVo;
    7. import org.junit.Test;
    8. import org.junit.runner.RunWith;
    9. import org.springframework.beans.factory.annotation.Autowired;
    10. import org.springframework.test.context.ContextConfiguration;
    11. import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    12.  
    13. import static org.junit.Assert.*;
    14.  
    15. /**
    16.  * @author 云鹤衫
    17.  * @site www.yunheshan.com
    18.  * @company xxx公司
    19.  * @create  2022-08-15 23:33
    20.  */
    21. @RunWith(SpringJUnit4ClassRunner.class)
    22. @ContextConfiguration(locations={"classpath:applicationContext-mybatis.xml"})
    23. public class OredeBizImplTest {
    24.     @Autowired
    25.     private OredeBiz oredeBiz;
    26.  
    27.     @Test
    28.     public void queryOrderVoByOrderId() {
    29.         OrderVo oredervo=oredeBiz.queryOrderVoByOrderId(9);
    30.         System.out.println(oredervo);
    31.     }
    32. }

     Oreder:

    1. package com.mgy.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，同时田间tostring方法
    9. /*@NoArgsConstructor
    10. @AllArgsConstructor*/
    11. @Data
    12. public class Oreder {
    13.     private Integer orderId;
    14.  
    15.     private String orderNo;
    16.  
    17.  
    18. }

    效果：

     ④、修改OrederItemMapper.xml:

    2. mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
    3. <mapper namespace="com.mgy.ssm.mapper.OrederItemMapper" >
    4.   <resultMap id="BaseResultMap" type="com.mgy.ssm.model.OrederItem" >
    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.  
    13.   <resultMap id="OrderItemVoMap" type="com.mgy.ssm.model.vo.OrederItemVo" >
    14.  
    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.     <association property="oreder" javaType="com.mgy.ssm.model.Oreder">
    20.       <result column="order_id" property="orderId">result>
    21.       <result column="order_no" property="orderNo">result>
    22.     association>
    23.  
    24.   resultMap>
    25.  
    26.   <sql id="Base_Column_List" >
    27.     order_item_id, product_id, quantity, oid
    28.   sql>
    29.  
    30.   <select id="queryOrderItemVoByOrderItemId" resultMap="OrderItemVoMap" parameterType="java.lang.Integer" >
    31.         select * from t_hibernate_order o,t_hibernate_order_item oi
    32.         where o.order_id = oi.oid and oi.order_item_id=#{orderItemId}
    33.   select>
    34.  
    35.  
    36.   <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    37.     select 
    38.     <include refid="Base_Column_List" />
    39.     from t_hibernate_order_item
    40.     where order_item_id = #{orderItemId,jdbcType=INTEGER}
    41.   select>
    42.   <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    43.     delete from t_hibernate_order_item
    44.     where order_item_id = #{orderItemId,jdbcType=INTEGER}
    45.   delete>
    46.   <insert id="insert" parameterType="com.mgy.ssm.model.OrederItem" >
    47.     insert into t_hibernate_order_item (order_item_id, product_id, quantity, 
    48.       oid)
    49.     values (#{orderItemId,jdbcType=INTEGER}, #{productId,jdbcType=INTEGER}, #{quantity,jdbcType=INTEGER}, 
    50.       #{oid,jdbcType=INTEGER})
    51.   insert>
    52.   <insert id="insertSelective" parameterType="com.mgy.ssm.model.OrederItem" >
    53.     insert into t_hibernate_order_item
    54.     <trim prefix="(" suffix=")" suffixOverrides="," >
    55.       <if test="orderItemId != null" >
    56.         order_item_id,
    57.       if>
    58.       <if test="productId != null" >
    59.         product_id,
    60.       if>
    61.       <if test="quantity != null" >
    62.         quantity,
    63.       if>
    64.       <if test="oid != null" >
    65.         oid,
    66.       if>
    67.     trim>
    68.     <trim prefix="values (" suffix=")" suffixOverrides="," >
    69.       <if test="orderItemId != null" >
    70.         #{orderItemId,jdbcType=INTEGER},
    71.       if>
    72.       <if test="productId != null" >
    73.         #{productId,jdbcType=INTEGER},
    74.       if>
    75.       <if test="quantity != null" >
    76.         #{quantity,jdbcType=INTEGER},
    77.       if>
    78.       <if test="oid != null" >
    79.         #{oid,jdbcType=INTEGER},
    80.       if>
    81.     trim>
    82.   insert>
    83.   <update id="updateByPrimaryKeySelective" parameterType="com.mgy.ssm.model.OrederItem" >
    84.     update t_hibernate_order_item
    85.     <set >
    86.       <if test="productId != null" >
    87.         product_id = #{productId,jdbcType=INTEGER},
    88.       if>
    89.       <if test="quantity != null" >
    90.         quantity = #{quantity,jdbcType=INTEGER},
    91.       if>
    92.       <if test="oid != null" >
    93.         oid = #{oid,jdbcType=INTEGER},
    94.       if>
    95.     set>
    96.     where order_item_id = #{orderItemId,jdbcType=INTEGER}
    97.   update>
    98.   <update id="updateByPrimaryKey" parameterType="com.mgy.ssm.model.OrederItem" >
    99.     update t_hibernate_order_item
    100.     set product_id = #{productId,jdbcType=INTEGER},
    101.       quantity = #{quantity,jdbcType=INTEGER},
    102.       oid = #{oid,jdbcType=INTEGER}
    103.     where order_item_id = #{orderItemId,jdbcType=INTEGER}
    104.   update>
    105. mapper>

     Collection:一对多的一方，对应关联属性用ofType

    Assoctation:一对多的多方，对应关联属性用javaType

    将以下方法加入到OrederItemMapper

        OrederItemVo queryOrderItemVoByOrderItemId(@Param("orderItemId")Integer orderItemId);

     生成接口：

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

    实现类：

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

     测试类：

    1. package com.mgy.ssm.biz.impl;
    2.  
    3. import com.mgy.ssm.biz.OrederItemBiz;
    4. import com.mgy.ssm.model.vo.OrederItemVo;
    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 云鹤衫
    15.  * @site www.yunheshan.com
    16.  * @company xxx公司
    17.  * @create  2022-08-16 0:36
    18.  */
    19. @RunWith(SpringJUnit4ClassRunner.class)
    20. @ContextConfiguration(locations={"classpath:applicationContext-mybatis.xml"})
    21. public class OrederItemBizImplTest {
    22.     @Autowired
    23.     private OrederItemBiz orederItemBiz;
    24.     @Test
    25.     public void queryOrderItemVoByOrderItemId() {
    26.        OrederItemVo orederItemVo= orederItemBiz.queryOrderItemVoByOrderItemId(43);
    27.         System.out.println(orederItemVo);
    28.     }
    29. }

     将@ToString加入到OrderItem类上

    效果： 

     

    二、多对多

    概念：比如一本书籍有多个类别，多个类别对多本书

     多对多就是两个一对多

    修改generatorConfig.xml，然后逆向生成

    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:\\Maven\\mvn_baoc\\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.mgy.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.mgy.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.mgy.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.  
    77.         <table schema="" tableName="t_hibernate_Book" domainObjectName="Hbook"
    78.                enableCountByExample="false" enableDeleteByExample="false"
    79.                enableSelectByExample="false" enableUpdateByExample="false">
    80.         table>
    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>

     ②、修改HbookCategoryMapper.xml

    2. mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
    3. <mapper namespace="com.mgy.ssm.mapper.HbookCategoryMapper" >
    4.   <resultMap id="BaseResultMap" type="com.mgy.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.mgy.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.mgy.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.mgy.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.mgy.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.   <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    44.     select 
    45.     <include refid="Base_Column_List" />
    46.     from t_hibernate_book_category
    47.     where bcid = #{bcid,jdbcType=INTEGER}
    48.   select>
    49.   <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    50.     delete from t_hibernate_book_category
    51.     where bcid = #{bcid,jdbcType=INTEGER}
    52.   delete>
    53.   <insert id="insert" parameterType="com.mgy.ssm.model.HbookCategory" >
    54.     insert into t_hibernate_book_category (bcid, bid, cid
    55.       )
    56.     values (#{bcid,jdbcType=INTEGER}, #{bid,jdbcType=INTEGER}, #{cid,jdbcType=INTEGER}
    57.       )
    58.   insert>
    59.   <insert id="insertSelective" parameterType="com.mgy.ssm.model.HbookCategory" >
    60.     insert into t_hibernate_book_category
    61.     <trim prefix="(" suffix=")" suffixOverrides="," >
    62.       <if test="bcid != null" >
    63.         bcid,
    64.       if>
    65.       <if test="bid != null" >
    66.         bid,
    67.       if>
    68.       <if test="cid != null" >
    69.         cid,
    70.       if>
    71.     trim>
    72.     <trim prefix="values (" suffix=")" suffixOverrides="," >
    73.       <if test="bcid != null" >
    74.         #{bcid,jdbcType=INTEGER},
    75.       if>
    76.       <if test="bid != null" >
    77.         #{bid,jdbcType=INTEGER},
    78.       if>
    79.       <if test="cid != null" >
    80.         #{cid,jdbcType=INTEGER},
    81.       if>
    82.     trim>
    83.   insert>
    84.   <update id="updateByPrimaryKeySelective" parameterType="com.mgy.ssm.model.HbookCategory" >
    85.     update t_hibernate_book_category
    86.     <set >
    87.       <if test="bid != null" >
    88.         bid = #{bid,jdbcType=INTEGER},
    89.       if>
    90.       <if test="cid != null" >
    91.         cid = #{cid,jdbcType=INTEGER},
    92.       if>
    93.     set>
    94.     where bcid = #{bcid,jdbcType=INTEGER}
    95.   update>
    96.   <update id="updateByPrimaryKey" parameterType="com.mgy.ssm.model.HbookCategory" >
    97.     update t_hibernate_book_category
    98.     set bid = #{bid,jdbcType=INTEGER},
    99.       cid = #{cid,jdbcType=INTEGER}
    100.     where bcid = #{bcid,jdbcType=INTEGER}
    101.   update>
    102. mapper>

    创建两个类

    1. package com.mgy.ssm.model.vo;
    2.  
    3. import com.mgy.ssm.model.Category;
    4. import com.mgy.ssm.model.Hbook;
    5.  
    6. import java.util.List;
    7.  
    8. /**
    9.  * @author 云鹤衫
    10.  * @site www.yunheshan.com
    11.  * @company xxx公司
    12.  * @create  2022-08-16 0:59
    13.  */
    14. public class HbookVo extends Hbook {
    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. }
    1. package com.mgy.ssm.model.vo;
    2.  
    3. import com.mgy.ssm.model.Category;
    4. import com.mgy.ssm.model.Hbook;
    5.  
    6. import java.util.List;
    7.  
    8. /**
    9.  * @author 云鹤衫
    10.  * @site www.yunheshan.com
    11.  * @company xxx公司
    12.  * @create  2022-08-16 1:10
    13.  */
    14. public class CategoryVo extends Category {
    15.     private List hbooks;
    16.  
    17.     public List getHbooks() {
    18.         return hbooks;
    19.     }
    20.  
    21.     public void setHbooks(List hbooks) {
    22.         this.hbooks = hbooks;
    23.     }
    24. }
    将以下代码加入HbookCategoryMapper中
    1.     HbookVo queryByBookId(@Param("bookId") Integer bookId);
    2.  
    3.     CategoryVo queryByCid(@Param("cid") Integer cid);

    Biz类：

    1. package com.mgy.ssm.biz;
    2.  
    3. import com.mgy.ssm.model.HbookCategory;
    4. import com.mgy.ssm.model.vo.CategoryVo;
    5. import com.mgy.ssm.model.vo.HbookVo;
    6. import org.apache.ibatis.annotations.Param;
    7.  
    8. public interface HbookCategoryBiz {
    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.  
    22.     HbookVo queryByBookId(Integer bookId);
    23.  
    24.     CategoryVo queryByCid(Integer cid);
    25.  
    26. }

    实现类：

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

     测试类：

    1. package com.mgy.ssm.biz.impl;
    2.  
    3.  
    4. import com.mgy.ssm.biz.HbookCategoryBiz;
    5. import com.mgy.ssm.model.vo.CategoryVo;
    6. import com.mgy.ssm.model.vo.HbookVo;
    7. import org.junit.Test;
    8. import org.junit.runner.RunWith;
    9. import org.springframework.beans.factory.annotation.Autowired;
    10. import org.springframework.test.context.ContextConfiguration;
    11. import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    12.  
    13. import static org.junit.Assert.*;
    14.  
    15. /**
    16.  * @author 云鹤衫
    17.  * @site www.yunheshan.com
    18.  * @company xxx公司
    19.  * @create  2022-08-16 1:39
    20.  */
    21. @RunWith(SpringJUnit4ClassRunner.class)
    22. @ContextConfiguration(locations={"classpath:applicationContext-mybatis.xml"})
    23. public class HbookCategoryBizImplTest {
    24.     @Autowired
    25.     private HbookCategoryBiz hbookCategoryBiz;
    26.  
    27.     @Test
    28.     public  void queryByBookId(){
    29.         HbookVo hbookVo=hbookCategoryBiz.queryByBookId(8);
    30.         System.out.println(hbookVo);
    31.         hbookVo.getCategories().forEach(System.out::println);
    32.     }
    33.  
    34.     @Test
    35.     public  void queryByCid(){
    36.         CategoryVo categoryVo=hbookCategoryBiz.queryByCid(8);
    37.         System.out.println(categoryVo);
    38.         categoryVo.getHbooks().forEach(System.out::println);
    39.     }
    40. }
    queryByBookId方法效果：

     queryByCid方法效果：

     

    
                
    
                    
    
                
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                    原文地址：https://blog.csdn.net/m0_62604616/article/details/126355709
                
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