[JAVAEE]实验07：MyBatis关联映射实践

一、实验目的：

掌握MyBatis的关联映射（一对一、一对多、多对多）

实验内容：

模拟用户批量购买理财产品的业务。用户（customer）一个批次（batch）可以购买多款理财产品（product）。

此业务逻辑涉及4张表:用户表、批次表、批次明细表、理财产品表。

（1）查询一个购买批次的信息以及创建该批次的用户；

（2）在（1）的基础上增加对该批次从属的理财产品信息的查询；

（3）查询所有用户以及用户对应的批次订单中所有理财产品的详细信息。

实验要求：

（1）提交源代码和运行截图。

二、设计：

用户和批次是一对一：批次表中用外键引用用户id

批次和理财产品是多对多：用batchdetail表明一一对应关系

表结构：

用户（用户表）

批次（批次表）

（批次明细表）

理财产品（理财产品表）

（1）查询一个购买批次的信息以及创建该批次的用户；

1.根据batchid查询批次，内部嵌套（2）这是一对一

2.根据cusid查询用户

（2）在（1）的基础上增加对该批次从属的理财产品信息的查询；

在2的基础上增加调用理财产品查询,根据batchid查询产品

(在写方法的时候是一对多)

（3）查询所有用户以及用户对应的批次订单中所有理财产品的详细信息。

查询所有

（多对多）

基本步骤：

1.数据库建立数据表
2.创建po持久化类
3.核心配置文件内部写好映射表位置
4.编写映射表（普通sql，一对一，一对多，多对多）
5.若映射表内使用了pojo类来打包结果集，则还需创建pojo类
6.编写操作接口Dao（名称和映射相同）
7.编写控制类调用Dao
8.编写测试类表用控制

三、代码：

项目结构.png

1.Sql建表语句：

/*
SQLyog 企业版 - MySQL GUI v8.14 
MySQL - 5.6.24 : Database - mybatis_test
*********************************************************************
*/


/*!40101 SET NAMES utf8 */;

/*!40101 SET SQL_MODE=''*/;

/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
CREATE DATABASE /*!32312 IF NOT EXISTS*/`mybatis_test` /*!40100 DEFAULT CHARACTER SET utf8 COLLATE utf8_bin */;

USE `mybatis_test`;

/*Table structure for table `batch` */

DROP TABLE IF EXISTS `batch`;

CREATE TABLE `batch` (
  `batch_id` int(11) NOT NULL AUTO_INCREMENT,
  `cus_id` int(11) NOT NULL COMMENT '创建批次用户id',
  `number` varchar(32) NOT NULL COMMENT '批次编码',
  `createtime` datetime NOT NULL COMMENT '创建批次时间',
  `note` varchar(100) DEFAULT NULL COMMENT '备注',
  PRIMARY KEY (`batch_id`),
  KEY `FK_batch_1` (`cus_id`),
  CONSTRAINT `FK_batch_id` FOREIGN KEY (`cus_id`) REFERENCES `customer` (`cus_id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

/*Data for the table `batch` */

insert  into `batch`(`batch_id`,`cus_id`,`number`,`createtime`,`note`) values (1,1,'00001','2017-07-22 00:00:00','首次购买'),(2,3,'00002','2017-03-11 00:00:00','委托购买');

/*Table structure for table `batchdetail` */

DROP TABLE IF EXISTS `batchdetail`;

CREATE TABLE `batchdetail` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `batch_id` int(11) NOT NULL COMMENT '批次id',
  `product_id` int(11) NOT NULL COMMENT '理财产品id',
  `product_num` int(11) DEFAULT NULL COMMENT '理财产品购买数量',
  PRIMARY KEY (`id`),
  KEY `FK_batchdetail_1` (`batch_id`),
  KEY `FK_batchdetail_2` (`product_id`),
  CONSTRAINT `FK_batchdetai_1` FOREIGN KEY (`batch_id`) REFERENCES `batch` (`batch_id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  CONSTRAINT `FK_batchdetai_2` FOREIGN KEY (`product_id`) REFERENCES `finacial_products` (`product_id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

/*Data for the table `batchdetail` */

insert  into `batchdetail`(`id`,`batch_id`,`product_id`,`product_num`) values (1,1,1,2),(2,1,2,1),(3,1,3,1),(4,2,1,2),(5,2,2,1);

/*Table structure for table `customer` */

DROP TABLE IF EXISTS `customer`;

CREATE TABLE `customer` (
  `cus_id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(32) NOT NULL COMMENT '用户名称',
  `acno` varchar(32) DEFAULT NULL COMMENT '卡号',
  `gender` varchar(4) DEFAULT NULL COMMENT '性别',
  `phone` varchar(256) DEFAULT NULL COMMENT '电话',
  PRIMARY KEY (`cus_id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

/*Data for the table `customer` */

insert  into `customer`(`cus_id`,`username`,`acno`,`gender`,`phone`) values (1,'刘云','6228286666666','男','13800000000'),(2,'李健','622848111111','男','13811111111'),(3,'张丽丽','622848333333','女','13822222222');

/*Table structure for table `finacial_products` */

DROP TABLE IF EXISTS `finacial_products`;

CREATE TABLE `finacial_products` (
  `product_id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(32) NOT NULL COMMENT '理财产品名称',
  `price` float(10,1) NOT NULL COMMENT '理财产品定价',
  `detail` text COMMENT '理财产品描述',
  `pic` varchar(64) DEFAULT NULL COMMENT '理财产品图片',
  `invasttime` datetime NOT NULL COMMENT '理财产品收益日期',
  PRIMARY KEY (`product_id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

/*Data for the table `finacial_products` */

insert  into `finacial_products`(`product_id`,`name`,`price`,`detail`,`pic`,`invasttime`) values (1,'一起富',5000.0,'投资少，风险小','img001','2017-06-21 00:00:00'),(2,'惠薪富',10000.0,'收益稳健','img002','2017-05-03 00:00:00'),(3,'安富尊容',15000.0,'年收益率提升5%','img003','2017-07-18 00:00:00'),(4,'富津利',2000.0,'企划收益率','img004','2017-04-11 00:00:00');

2.配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:tx="http://www.springframework.org/schema/tx" 
	xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/tx
		http://www.springframework.org/schema/tx/spring-tx.xsd">
    <!-- 指定需要扫描的包（包括子包），使注解生效 -->  
    <context:component-scan base-package="com.dao"/>
    <context:component-scan base-package="com.controller"/>
    <!-- 配置数据源 -->
	<bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource">
			<property name="driverClassName" value="com.mysql.jdbc.Driver" />
			<property name="url" value="jdbc:mysql://localhost:3306/mybatis_test?characterEncoding=utf8" />
			<property name="username" value="root" />
			<property name="password" value="363316495" />
			<!-- 最大连接数 -->
			<property name="maxTotal" value="30"/>
			<!-- 最大空闲连接数 -->
			<property name="maxIdle" value="10"/>
			<!-- 初始化连接数 -->
			<property name="initialSize" value="5"/>
	</bean>
	
	
	<!-- 添加事务支持 -->
	<bean id="txManager"   
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">   
        <property name="dataSource" ref="dataSource" />   
    </bean> 
    <!-- 开启事务注解-->
	<tx:annotation-driven transaction-manager="txManager" />
	
	
	
	
 	<!-- 配置MyBatis工厂，同时指定数据源，并与MyBatis完美整合 -->  
 	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">  
        <property name="dataSource" ref="dataSource" />  
        <!-- configLocation的属性值为MyBatis的核心配置文件 -->
        <property name="configLocation" value="classpath:com/mybatis/mybatis-config.xml"/>
    </bean>  
    
    
	<!--Mapper代理开发，使用Spring自动扫描MyBatis的接口并装配
 	（Spring将指定包中所有被@Mapper注解标注的接口自动装配为MyBatis的映射接口）  --> 
     <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
     	<!-- mybatis-spring组件的扫描器 -->
     	<property name="basePackage" value="com.dao"/>
     	<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
     </bean>
</beans>

3.持久化类po

Batch.java
package com.po;

import java.util.Date;
import java.util.List;

public class Batch {
	private int id;
	private String number;
	private Date createtime;
	private String note;
	
	//与顾客是一对一
	private Customer customer;
	
	//与订单是多对多
	private List<Product> products;
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public Customer getCustomer() {
		return customer;
	}
	public void setCustomer(Customer customer) {
		this.customer = customer;
	}
	public String getNumber() {
		return number;
	}
	public void setNumber(String number) {
		this.number = number;
	}
	public Date getCreatetime() {
		return createtime;
	}
	public void setCreatetime(Date createtime) {
		this.createtime = createtime;
	}
	public String getNote() {
		return note;
	}
	public void setNote(String note) {
		this.note = note;
	}
	public List<Product> getProducts() {
		return products;
	}
	public void setProducts(List<Product> products) {
		this.products = products;
	}
	@Override
	public String toString() {
		return "Batch [id=" + id + ", createtime=" + createtime
				+ ", note=" + note + "]";
	}
}

Customer.java

package com.po;
public class Customer {
	private int id;
	private String username;
	private String acno;
	private String gender;
	private String phone;
	
	
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getAcno() {
		return acno;
	}
	public void setAcno(String acno) {
		this.acno = acno;
	}
	public String getGender() {
		return gender;
	}
	public void setGender(String gender) {
		this.gender = gender;
	}
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	
	@Override
	public String toString() {
		return "Customer [id=" + id + ", username=" + username + ", acno=" + acno + ", gender=" + gender + ", phone="
				+ phone + "]";
	}
	
}

Product.java

package com.po;

import java.util.Date;
import java.util.List;
//对应表finacial_products
public class Product {
	
	private int product_id;
	private String name;
	private int price;
	private String detail;
	private String pic;
	private Date invasttime;
	
	//与batch是多对多
	private List<Batch> Batch;
	
	public int getProduct_id() {
		return product_id;
	}
	public void setId(int product_id) {
		this.product_id = product_id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getPrice() {
		return price;
	}
	public void setPrice(int price) {
		this.price = price;
	}
	public String getDetail() {
		return detail;
	}
	public void setDetail(String detail) {
		this.detail = detail;
	}
	public String getPic() {
		return pic;
	}
	public void setPic(String pic) {
		this.pic = pic;
	}
	public Date getInvasttime() {
		return invasttime;
	}
	public void setInvasttime(Date invasttime) {
		this.invasttime = invasttime;
	}
	
	
	public List<Batch> getOrders() {
		return Batch;
	}
	public void setOrders(List<Batch> Batch) {
		this.Batch = Batch;
	}
	
	
	@Override
	public String toString() {
		return "Product product_id=" + product_id + ", name=" + name + ", price=" + price + ", detail=" + detail + ", pic=" + pic
				+ ", invasttime=" + invasttime + "]";
	}
	
}

4.mybatis(非核心映射文件是sql和xml之间的桥梁)

mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
	<!-- 在使用MyBatis嵌套查询方式进行关联查询时，使用MyBatis的延迟加载在一定程度可以提高查询效率 -->
	<settings>
		<!-- 打开延迟加载的开关 -->
		<setting name="lazyLoadingEnabled" value="true"/>
		<!-- 将积极加载改为按需加载 -->
		<setting name="aggressiveLazyLoading" value="false"/>
	</settings>

	 <mappers><!-- 映射器，告诉 MyBatis到哪里去找映射文件-->
        <mapper resource="com/mybatis/CustomerMapper.xml"/>
        <mapper resource="com/mybatis/BatchMapper.xml"/>
       
       
 	</mappers>
</configuration>

BatchMapper.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.dao.BatchDao">
	
	
	<!-- 一、一对一 根据batchid查询：第三种方法（使用POJO存储结果） -->
	<!-- 先找batch再找批次对应的用户 -->
	<select id="selectBatchById" parameterType="Integer" resultType="com.pojo.SelectBatchById">
		select bat.*,cus.cus_id
		from batch bat, customer cus
		where bat.cus_id = cus.cus_id and bat.batch_id=#{id}
	</select>
	
	
	<!--二、 一对多 根据batchid查询用户及其关联的订单信息：第三种方法（使用POJO存储结果） -->
	<!-- 注意这里的sql语句，一定要写规范！ 我在from这里多写了一个batch的表就导致输出的结果是原来的两倍-->
	<select id="selectBatchProductById" parameterType="Integer" resultType="com.pojo.SelectBatchProductById">
		select pro.product_id,pro.name
		from  finacial_products pro,batchdetail detail 
		where detail.product_id = pro.product_id and detail.batch_id=#{id}
	</select>
	
	
	<!--三、查询所有用户以及用户对应的批次订单中所有理财产品的详细信息  -->
	<select id="selectallBatchAndProducts"   resultType="com.pojo.allBatchAndProducts">
		select cus.cus_id,bat.batch_id,pro.product_id
		from customer cus,batch bat,batchdetail detail,finacial_products pro
		where detail.batch_id = bat.batch_id 
		and detail.product_id = pro.product_id
		and bat.cus_id = cus.cus_id 
	</select>
	
	
	
</mapper>

CustomerMapper.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">
<!--绑定数据操作接口  -->
<mapper namespace="com.dao.CustomerDao">

<!-- sql与xml的映射文件 -->
	<select id="selectCustomerByid" parameterType="Integer" resultType="com.po.Customer">
		select * from customer where cus_id=#{id}
	</select>
</mapper>

5.pojo结果集（最方便）

allBatchAndProducts.java

package com.pojo;

public class allBatchAndProducts {
	String cus_id;
	String batch_id;
	String product_id;
	
	public String getcus_id() {
		return cus_id;
	}
	public void setcus_id(String cus_id) {
		this.cus_id = cus_id;
	}
	
	
	
	public String getGender() {
		return product_id;
	}
	public void setbatch_id(String batch_id) {
		this.batch_id = batch_id;
	}
	
	
	
	public String getproduct_id() {
		return product_id;
	}
	public void setproduct_id(String product_id) {
		this.product_id = product_id;
	}
	
	@Override
	public String toString() {
		return "Customer [cus_id=" + cus_id + ", batch_id=" + batch_id + ", product_id=" + product_id+ "]";
	}
}

SelectBatchById.java

package com.pojo;

import java.util.Date;


public class SelectBatchById {
	private int id;
	private String number;
	private Date createtime;
	private String note;
	
	//与顾客是一对一
	private String cus_id;
	
	
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}

	
	public String getNumber() {
		return number;
	}
	public void setNumber(String number) {
		this.number = number;
	}
	public Date getCreatetime() {
		return createtime;
	}
	public void setCreatetime(Date createtime) {
		this.createtime = createtime;
	}
	public String getNote() {
		return note;
	}
	public void setNote(String note) {
		this.note = note;
	}
	
	
	
	public String getCusid() {
		return cus_id;
	}
	public void setCusid(String cusid) {
		this.cus_id = cusid;
	}
	
	
	@Override
	public String toString() {
		return "Batch [id=" + id + ", createtime=" + createtime
				+ ", note=" + note + ", cus_id=" + cus_id +"]";
	}
	
}

SelectBatchProductById.java

package com.pojo;

public class SelectBatchProductById {

	String  product_id;
	String  name;
	
	public String getproduct_id() {
		return product_id;
	}
	public void setproduct_id(String product_id) {
		this.product_id = product_id;
	}
	
	
	public String getname() {
		return name;
	}
	public void setname(String name) {
		this.name = name;
	}
	
	@Override
	public String toString() {
		return "Batch [product_id=" + product_id + ", name=" + name +"]";
	}
	
	
}

6.Dao 数据操作类

BatchDao.java

package com.dao;
import java.util.List;

import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import com.pojo.SelectBatchById;
import com.pojo.SelectBatchProductById;
import com.pojo.allBatchAndProducts;

//说句操纵接口（要和mapper一一对应）

@Repository("BatchDao")
@Mapper
public interface BatchDao {
	
	public SelectBatchById selectBatchById(Integer id);
	
	//一对多
	public List<SelectBatchProductById> selectBatchProductById(Integer id);
	
	//多对多
	public  List<allBatchAndProducts> selectallBatchAndProducts() ;
		
}

CustomerDao.java

package com.dao;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import com.po.Customer;

@Repository("CustomerDao")
@Mapper


public interface CustomerDao {
	public Customer selectCustomerByid(Integer i);
}

7.控制和测试类

(名字我复制的，可以随意改)

OneToOneController.java

package com.controller;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import com.dao.BatchDao;

import com.pojo.SelectBatchById;
import com.pojo.SelectBatchProductById;
import com.pojo.allBatchAndProducts;

@Controller("oneToOneController")
public class OneToOneController {
	@Autowired
	private BatchDao batchDao;
	public void test() {
		
		//一对一
		SelectBatchById p = batchDao.selectBatchById(1);
		System.out.println("查询一个购买批次的信息以及创建该批次的用户:");
		System.out.println(p);
		
		//一对多
		List<SelectBatchProductById> p1 = batchDao.selectBatchProductById(1);
		System.out.println("增加对该批次从属的理财产品信息的查询:");
		for (SelectBatchProductById ppp : p1) {
			System.out.println(ppp);
		}

		
		//多对多
		System.out.println("查询所有用户以及用户对应的批次订单中所有理财产品的详细信息:");
		List<allBatchAndProducts> bat = batchDao.selectallBatchAndProducts();
		for (allBatchAndProducts i : bat) {
			System.out.println(i);
		}
		
		
	}
}

TestOneToOne.java测试

package com.controller;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestOneToOne {
	public static void main(String[] args) {
		@SuppressWarnings("resource")
		ApplicationContext appCon = new ClassPathXmlApplicationContext("applicationContext.xml");
		OneToOneController oto = (OneToOneController)appCon.getBean("oneToOneController");
		oto.test();
	}
}

四、运行结果

批次和用户1：1.png

批次和产品1：n.png

输出全部.png

原文链接：https://blog.csdn.net/weixin_40486026/article/details/90241759

一、实验目的：

二、设计：

基本步骤：

三、代码：

四、运行结果

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