Java SMM框架關(guān)聯(lián)關(guān)系映射示例講解

更新時(shí)間：2022年08月16日 15:03:10 作者：小謝同學(xué)189

SSM框架是spring MVC ，spring和mybatis框架的整合，是標(biāo)準(zhǔn)的MVC模式，將整個(gè)系統(tǒng)劃分為表現(xiàn)層，controller層，service層，DAO層四層，使用spring MVC負(fù)責(zé)請(qǐng)求的轉(zhuǎn)發(fā)和視圖管理，spring實(shí)現(xiàn)業(yè)務(wù)對(duì)象管理，mybatis作為數(shù)據(jù)對(duì)象的持久化引擎

一、一對(duì)多關(guān)聯(lián)關(guān)系

需求：通過訂單號(hào)查詢本次訂單的詳情信息以及對(duì)應(yīng)的所有訂單

1.1 逆向生成代碼配置文件

generatorConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd" >
<generatorConfiguration>
    <!-- 引入配置文件 -->
    <properties resource="jdbc.properties"/>
    <!--指定數(shù)據(jù)庫(kù)jdbc驅(qū)動(dòng)jar包的位置-->
    <classPathEntry location="E:\\maven\\mavenjar\\mysql\\mysql-connector-java\\5.1.44\\mysql-connector-java-5.1.44.jar"/>
    <!-- 一個(gè)數(shù)據(jù)庫(kù)一個(gè)context -->
    <context id="infoGuardian">
        <!-- 注釋 -->
        <commentGenerator>
            <property name="suppressAllComments" value="true"/><!-- 是否取消注釋 -->
            <property name="suppressDate" value="true"/> <!-- 是否生成注釋代時(shí)間戳 -->
        </commentGenerator>
        <!-- jdbc連接 -->
        <jdbcConnection driverClass="${jdbc.driver}"
                        connectionURL="${jdbc.url}" userId="${jdbc.username}" password="${jdbc.password}"/>
        <!-- 類型轉(zhuǎn)換 -->
        <javaTypeResolver>
            <!-- 是否使用bigDecimal， false可自動(dòng)轉(zhuǎn)化以下類型（Long, Integer, Short, etc.） -->
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!-- 01 指定javaBean生成的位置 -->
        <!-- targetPackage：指定生成的model生成所在的包名 -->
        <!-- targetProject：指定在該項(xiàng)目下所在的路徑  -->
        <javaModelGenerator targetPackage="com.xlb.ssm.model"
                            targetProject="src/main/java">
            <!-- 是否允許子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" value="false"/>
            <!-- 是否對(duì)model添加構(gòu)造函數(shù) -->
            <property name="constructorBased" value="true"/>
            <!-- 是否針對(duì)string類型的字段在set的時(shí)候進(jìn)行trim調(diào)用 -->
            <property name="trimStrings" value="false"/>
            <!-- 建立的Model對(duì)象是否 不可改變  即生成的Model對(duì)象不會(huì)有 setter方法，只有構(gòu)造方法 -->
            <property name="immutable" value="false"/>
        </javaModelGenerator>
        <!-- 02 指定sql映射文件生成的位置 -->
        <sqlMapGenerator targetPackage="com.xlb.ssm.mapper"
                         targetProject="src/main/java">
            <!-- 是否允許子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" value="false"/>
        </sqlMapGenerator>
        <!-- 03 生成XxxMapper接口 -->
        <!-- type="ANNOTATEDMAPPER",生成Java Model 和基于注解的Mapper對(duì)象 -->
        <!-- type="MIXEDMAPPER",生成基于注解的Java Model 和相應(yīng)的Mapper對(duì)象 -->
        <!-- type="XMLMAPPER",生成SQLMap XML文件和獨(dú)立的Mapper接口 -->
        <javaClientGenerator targetPackage="com.xlb.ssm.mapper"
                             targetProject="src/main/java" type="XMLMAPPER">
            <!-- 是否在當(dāng)前路徑下新加一層schema,false路徑com.oop.eksp.user.model， true:com.oop.eksp.user.model.[schemaName] -->
            <property name="enableSubPackages" value="false"/>
        </javaClientGenerator>
        <!-- 配置表信息 -->
        <!-- schema即為數(shù)據(jù)庫(kù)名 -->
        <!-- tableName為對(duì)應(yīng)的數(shù)據(jù)庫(kù)表 -->
        <!-- domainObjectName是要生成的實(shí)體類 -->
        <!-- enable*ByExample是否生成 example類 -->
        <!--<table schema="" tableName="t_book" domainObjectName="Book"-->
        <!--enableCountByExample="false" enableDeleteByExample="false"-->
        <!--enableSelectByExample="false" enableUpdateByExample="false">-->
        <!--<!&ndash; 忽略列，不生成bean 字段 &ndash;>-->
        <!--<!&ndash; <ignoreColumn column="FRED" /> &ndash;>-->
        <!--<!&ndash; 指定列的java數(shù)據(jù)類型 &ndash;>-->
        <!--<!&ndash; <columnOverride column="LONG_VARCHAR_FIELD" jdbcType="VARCHAR" /> &ndash;>-->
        <!--</table>-->
       <table schema="" tableName="t_hibernate_order" domainObjectName="Order"
               enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false">
        </table>
        <table schema="" tableName="t_hibernate_order_item" domainObjectName="OrderItem"
               enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false">
        </table>
    </context>
</generatorConfiguration>

1.2 編寫配置文件OrderMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.xlb.ssm.mapper.OrderMapper" >
  <resultMap id="BaseResultMap" type="com.xlb.ssm.model.Order" >
    <constructor >
      <idArg column="order_id" jdbcType="INTEGER" javaType="java.lang.Integer" />
      <arg column="order_no" jdbcType="VARCHAR" javaType="java.lang.String" />
    </constructor>
  </resultMap>
  <sql id="Base_Column_List" >
    order_id, order_no
  </sql>
  <resultMap id="OrderVoMap" type="com.xlb.ssm.model.vo.OrderVo" >
    <result column="order_id" property="orderId"></result>
    <result column="order_no" property="orderNo"></result>
    <collection property="orderItems" ofType="com.xlb.ssm.model.OrderItem">
      <result column="order_item_id" property="orderItemId"></result>
      <result column="product_id" property="productId"></result>
      <result column="quantity" property="quantity"></result>
      <result column="oid" property="oid"></result>
    </collection>
  </resultMap>
  <select id="queryOrderVoByOrderId" resultMap="OrderVoMap" parameterType="java.lang.Integer" >
    select * from t_hibernate_order o,t_hibernate_order_item oi
    where o.order_id = oi.oid and o.order_id = #{orderId}
  </select>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from t_hibernate_order
    where order_id = #{orderId,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from t_hibernate_order
    where order_id = #{orderId,jdbcType=INTEGER}
  </delete>
  <insert id="insert" parameterType="com.xlb.ssm.model.Order" >
    insert into t_hibernate_order (order_id, order_no)
    values (#{orderId,jdbcType=INTEGER}, #{orderNo,jdbcType=VARCHAR})
  </insert>
  <insert id="insertSelective" parameterType="com.xlb.ssm.model.Order" >
    insert into t_hibernate_order
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="orderId != null" >
        order_id,
      </if>
      <if test="orderNo != null" >
        order_no,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="orderId != null" >
        #{orderId,jdbcType=INTEGER},
      </if>
      <if test="orderNo != null" >
        #{orderNo,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="com.xlb.ssm.model.Order" >
    update t_hibernate_order
    <set >
      <if test="orderNo != null" >
        order_no = #{orderNo,jdbcType=VARCHAR},
      </if>
    </set>
    where order_id = #{orderId,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.xlb.ssm.model.Order" >
    update t_hibernate_order
    set order_no = #{orderNo,jdbcType=VARCHAR}
    where order_id = #{orderId,jdbcType=INTEGER}
  </update>
</mapper>

1.3 建立Vo類

BookVo:

package com.xlb.ssm.model.vo;
import com.xlb.ssm.model.Order;
import com.xlb.ssm.model.OrderItem;
import java.util.List;
/**
 * Vo類不僅僅包含當(dāng)前表的信息、還能包含相關(guān)聯(lián)的表的信息
 *
 * 當(dāng)前訂單會(huì)有一個(gè)或者多個(gè)訂單項(xiàng)，多個(gè)訂單先必須要集合進(jìn)行接受
 */
public class OrderVo extends Order {
    //需求1：通過訂單號(hào)查詢本次訂單的詳情信息及對(duì)應(yīng)的所有訂單
    private List<OrderItem> orderItems;
    public List<OrderItem> getOrderItems() {
        return orderItems;
    }
    public void setOrderItems(List<OrderItem> 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;
/**
 *
 * 某一個(gè)訂單項(xiàng)一定屬于某個(gè)訂單的
 */
@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注釋：省略了get、set、toString、構(gòu)造方法。

再然后分別在OrderMapper.java 和 OrderBiz 里面添加查詢的方法

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

創(chuàng)建實(shí)現(xiàn)類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;
    }
}

測(cè)試類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：通過訂單號(hào)查詢本次訂單的詳情信息及對(duì)應(yīng)的所有訂單
    //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);
        //打印訂單項(xiàng)
        System.out.println(orderVo.getOrderItems());
    }
}

結(jié)果

二、多對(duì)對(duì)

需求:根據(jù)書籍id，查詢書籍信息以及所屬類別信息；

2.1 逆向生成代碼

配置要生成的實(shí)體類：generatorConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd" >
<generatorConfiguration>
    <!-- 引入配置文件 -->
    <properties resource="jdbc.properties"/>
    <!--指定數(shù)據(jù)庫(kù)jdbc驅(qū)動(dòng)jar包的位置-->
    <classPathEntry location="E:\\maven\\mavenjar\\mysql\\mysql-connector-java\\5.1.44\\mysql-connector-java-5.1.44.jar"/>
    <!-- 一個(gè)數(shù)據(jù)庫(kù)一個(gè)context -->
    <context id="infoGuardian">
        <!-- 注釋 -->
        <commentGenerator>
            <property name="suppressAllComments" value="true"/><!-- 是否取消注釋 -->
            <property name="suppressDate" value="true"/> <!-- 是否生成注釋代時(shí)間戳 -->
        </commentGenerator>
        <!-- jdbc連接 -->
        <jdbcConnection driverClass="${jdbc.driver}"
                        connectionURL="${jdbc.url}" userId="${jdbc.username}" password="${jdbc.password}"/>
        <!-- 類型轉(zhuǎn)換 -->
        <javaTypeResolver>
            <!-- 是否使用bigDecimal， false可自動(dòng)轉(zhuǎn)化以下類型（Long, Integer, Short, etc.） -->
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!-- 01 指定javaBean生成的位置 -->
        <!-- targetPackage：指定生成的model生成所在的包名 -->
        <!-- targetProject：指定在該項(xiàng)目下所在的路徑  -->
        <javaModelGenerator targetPackage="com.xlb.ssm.model"
                            targetProject="src/main/java">
            <!-- 是否允許子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" value="false"/>
            <!-- 是否對(duì)model添加構(gòu)造函數(shù) -->
            <property name="constructorBased" value="true"/>
            <!-- 是否針對(duì)string類型的字段在set的時(shí)候進(jìn)行trim調(diào)用 -->
            <property name="trimStrings" value="false"/>
            <!-- 建立的Model對(duì)象是否 不可改變  即生成的Model對(duì)象不會(huì)有 setter方法，只有構(gòu)造方法 -->
            <property name="immutable" value="false"/>
        </javaModelGenerator>
        <!-- 02 指定sql映射文件生成的位置 -->
        <sqlMapGenerator targetPackage="com.xlb.ssm.mapper"
                         targetProject="src/main/java">
            <!-- 是否允許子包，即targetPackage.schemaName.tableName -->
            <property name="enableSubPackages" value="false"/>
        </sqlMapGenerator>
        <!-- 03 生成XxxMapper接口 -->
        <!-- type="ANNOTATEDMAPPER",生成Java Model 和基于注解的Mapper對(duì)象 -->
        <!-- type="MIXEDMAPPER",生成基于注解的Java Model 和相應(yīng)的Mapper對(duì)象 -->
        <!-- type="XMLMAPPER",生成SQLMap XML文件和獨(dú)立的Mapper接口 -->
        <javaClientGenerator targetPackage="com.xlb.ssm.mapper"
                             targetProject="src/main/java" type="XMLMAPPER">
            <!-- 是否在當(dāng)前路徑下新加一層schema,false路徑com.oop.eksp.user.model， true:com.oop.eksp.user.model.[schemaName] -->
            <property name="enableSubPackages" value="false"/>
        </javaClientGenerator>
        <!-- 配置表信息 -->
        <!-- schema即為數(shù)據(jù)庫(kù)名 -->
        <!-- tableName為對(duì)應(yīng)的數(shù)據(jù)庫(kù)表 -->
        <!-- domainObjectName是要生成的實(shí)體類 -->
        <!-- enable*ByExample是否生成 example類 -->
        <!--<table schema="" tableName="t_book" domainObjectName="Book"-->
        <!--enableCountByExample="false" enableDeleteByExample="false"-->
        <!--enableSelectByExample="false" enableUpdateByExample="false">-->
        <!--&lt;!&ndash; 忽略列，不生成bean 字段 &ndash;&gt;-->
        <!--&lt;!&ndash; <ignoreColumn column="FRED" /> &ndash;&gt;-->
        <!--&lt;!&ndash; 指定列的java數(shù)據(jù)類型 &ndash;&gt;-->
        <!--&lt;!&ndash; <columnOverride column="LONG_VARCHAR_FIELD" jdbcType="VARCHAR" /> &ndash;&gt;-->
        <!--</table>-->
      <table schema="" tableName="t_hibernate_book" domainObjectName="Hbook"
               enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false">
        </table>
        <table schema="" tableName="t_hibernate_category" domainObjectName="Category"
               enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false">
        </table>
        <table schema="" tableName="t_hibernate_book_category" domainObjectName="HbookCategory"
               enableCountByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" enableUpdateByExample="false">
        </table>
    </context>
</generatorConfiguration>

2.2 創(chuàng)建Vo類

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<Hbook> hbooks;
    public List<Hbook> getHbooks() {
        return hbooks;
    }
    public void setHbooks(List<Hbook> 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<Category> categories;
    public List<Category> getCategories() {
        return categories;
    }
    public void setCategories(List<Category> categories) {
        this.categories = categories;
    }
}

創(chuàng)建實(shí)現(xiàn)類：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);
    }
}

然后再創(chuàng)建測(cè)試類進(jìn)行測(cè)試：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);
    }
}

結(jié)果

到此這篇關(guān)于Java SMM框架關(guān)聯(lián)關(guān)系映射示例講解的文章就介紹到這了,更多相關(guān)SSM關(guān)聯(lián)關(guān)系映射內(nèi)容請(qǐng)搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！

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