Mybatis 一对多(OneToOne)关系映射_mybatisplus onetoone

作者：繁依Fanyi0 | 2024-05-03 18:06:05

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mybatisplus onetoone

标签： Mybatis 一对多(OneToOne)关系映射

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关于MyBatis一对多的设置如下:

1.创建数据库脚本

CREATE TABLE t_customer(
  id int(10) not null auto_increment,
  address varchar(120),
  postcode varchar(6),
  sex varchar(2),
  cname varchar(24),
   primary key(id)
)charset="GB2312";

CREATE TABLE t_orders(
  id int(10) not null auto_increment,
  code varchar(24),
  customer_id int(3) not null,
   primary key(id)
)charset="GB2312";

ALTER TABLE t_orders
ADD CONSTRAINT orders_customer_fk FOREIGN KEY (customer_id) REFERENCES t_customer(id)

-- t_orders.customer_id 参照 t_customer.id

2.创建实体类(POJO)

Customer.java

package com.lixing.ibatis.entity.onetomany;

import java.io.Serializable;
import java.util.List;

public class Customer implements Serializable{
   private static final long serialVersionUID = 451949797460417653L;
   private int id;
   private String address;
   private String postcode;
   private String sex;
   private String cname;
   private List<Orders> orders;   //一个Customer 对应N多个Orders

   public int getId() {
     return id;
  }
   public void setId( int id) {
     this.id = id;
  }
   public String getAddress() {
     return address;
  }
   public void setAddress(String address) {
     this.address = address;
  }
   public String getPostcode() {
     return postcode;
  }
   public void setPostcode(String postcode) {
     this.postcode = postcode;
  }
   public String getSex() {
     return sex;
  }
   public void setSex(String sex) {
     this.sex = sex;
  }
   public String getCname() {
     return cname;
  }
   public void setCname(String cname) {
     this.cname = cname;
  }
   public List<Orders> getOrders() {
     return orders;
  }
   public void setOrders(List<Orders> orders) {
     this.orders = orders;
  }
}

Orders.java

package com.lixing.ibatis.entity.onetomany;

import java.io.Serializable;

public class Orders implements Serializable {
   private static final long serialVersionUID = 8215977396669780567L;
   private int id;
   private String code;
   private int customerId;
   private Customer customer; //多个Orders对应一个Customer

   public int getId() {
     return id;
  }

   public void setId( int id) {
     this.id = id;
  }

   public String getCode() {
     return code;
  }

   public void setCode(String code) {
     this.code = code;
  }

   public int getCustomerId() {
     return customerId;
  }

   public void setCustomerId( int customerId) {
     this.customerId = customerId;
  }

   public Customer getCustomer() {
     return customer;
  }

   public void setCustomer(Customer customer) {
     this.customer = customer;
  }
}

3.创建Mapper映射接口

CustomerMapper.java

package com.lixing.ibatis.onetomany.mapper;

import com.lixing.ibatis.entity.onetomany.Customer;

public interface CustomerMapper {
void insertCustomer(Customer customer);
Customer getCustomer( int id);
}

OrdersMapper.java

package com.lixing.ibatis.onetomany.mapper;

import java.util.List;

import com.lixing.ibatis.entity.onetomany.Orders;

public interface OrdersMapper {
   void insertOrders(Orders orders);
  List<Orders> getOrders( int id);    //根据id
  List<Orders> getOrdersById( int customerId);   //根据customerId获得N多个对象
}

4.创建Mapper XML配置文件

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">
< mapper namespace ="com.lixing.ibatis.onetomany.mapper.CustomerMapper" >
   < parameterMap type ="Customer" id ="parameterCustomerMap" >
     < parameter property ="id" />
     < parameter property ="address" />
     < parameter property ="postcode" />
     < parameter property ="sex" />
     < parameter property ="cname" />
   </ parameterMap >

   < insert id ="insertCustomer" parameterMap ="parameterCustomerMap" >
     < selectKey     keyProperty ="id" resultType ="int" order ="AFTER" >
      SELECT @@IDENTITY AS ID
     </ selectKey >
    INSERT INTO t_customer(address,postcode,sex,cname)
    VALUES(#{address},#{postcode},#{sex},#{cname})
   </ insert >

   < resultMap type ="Customer" id ="resultCustomerMap" >
     < result property ="id" column ="id" />
     < result property ="address" column ="address" />
     < result property ="postcode" column ="postcode" />
     < result property ="sex" column ="sex" />
     < result property ="cname" column ="cname" />
     <collection property="orders" column="id" select="com.lixing.ibatis.onetomany.mapper.OrdersMapper.getOrdersById"/>
   </ resultMap >

   < select id ="getCustomer" resultMap ="resultCustomerMap" parameterType ="int" >
    SELECT *
    FROM t_customer
    WHERE id=#{id}
   </ select >
</ mapper >

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.lixing.ibatis.onetomany.mapper.OrdersMapper" >
   < parameterMap type ="Orders" id ="parameterOrdersMap" >
     < parameter property ="id" />
     < parameter property ="code" />
     < parameter property ="customerId" />
   </ parameterMap >

   < insert id ="insertOrders"     parameterMap ="parameterOrdersMap" >
     < selectKey     keyProperty ="id" resultType ="int" order ="AFTER" >
      SELECT LAST_INSERT_ID() AS ID
     </ selectKey >
    INSERT INTO t_orders(code,customer_id)
    VALUES(#{code},#{customerId})
   </ insert >

   < resultMap type ="Orders" id ="ordersMap" >
     < result property ="id" column ="id" />
     < result property ="code" column ="name" />
     < result property ="customerId" column ="customer_id" />
     < association property ="customer" javaType ="Customer" column ="customer_id" select ="com.lixing.ibatis.onetomany.mapper.CustomerMapper.getCustomer" />
   </ resultMap >
   < select id ="getOrders" resultMap ="ordersMap" parameterType ="int" >
    SELECT * FROM t_orders
    WHERE id=#{id}
   </ select >

   < select id ="getOrdersById" resultMap ="ordersMap" parameterType ="int" >
    SELECT * FROM t_orders
    WHERE customer_id=#{customer_id}
   </ select >

</ mapper >

5.mybatis-config.xml 文件

<? 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 >
   < settings >
    
     < setting name ="cacheEnabled" value ="false" />
     < setting name ="useGeneratedKeys" value ="true" />
     < setting name ="defaultExecutorType" value ="REUSE" />
   </ settings >

   < typeAliases >
     < typeAlias type ="com.lixing.ibatis.entity.onetomany.Customer" alias ="Customer" />
     < typeAlias type ="com.lixing.ibatis.entity.onetomany.Orders" alias ="Orders" />

   </ typeAliases >

   < environments default ="development" >
     < environment id ="development" >
       < transactionManager type ="JDBC" />
       < dataSource type ="POOLED" >
         < property name ="driver" value ="com.mysql.jdbc.Driver" />
         < property name ="url" value ="jdbc:mysql://localhost:3306/test" />
         < property name ="username" value ="root" />
         < property name ="password" value ="7501857" />
       </ dataSource >
     </ environment >
   </ environments >
   < mappers >
     < mapper resource ="com/lixing/ibatis/onetomany/mapper/CustomerMapper.xml" />
     < mapper resource ="com/lixing/ibatis/onetomany/mapper/OrdersMapper.xml" />
   </ mappers >
</ configuration >

6.创建测试类

package com.lixing.ibatis.test;

import java.util.Iterator;
import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.lixing.ibatis.entity.onetomany.Customer;
import com.lixing.ibatis.entity.onetomany.Orders;
import com.lixing.ibatis.onetomany.mapper.CustomerMapper;
import com.lixing.ibatis.onetomany.mapper.OrdersMapper;
import com.lixing.ibatis.util.MyBatisUtil;

public class OrdersMapperTest {
   private SqlSessionFactory sqlSessionFactory= null;
   private SqlSession session= null;

  @Before
   public void before(){
    sqlSessionFactory=MyBatisUtil.getInstance();
    session=sqlSessionFactory.openSession();
  }

  @Test
   public void testInsertOrders(){
    Orders orders= new Orders();
    orders.setCode( "code__1");
    orders.setCustomerId(1);

    OrdersMapper ordersMapper=session.getMapper(OrdersMapper. class);
    ordersMapper.insertOrders(orders);
    session.commit();
  }

  @Test
   public void testInsertCustomerOneToMany(){
    Customer customer= new Customer();
    customer.setCname( "Lixing5");
    customer.setPostcode( "518105");
    customer.setSex( "男");
    customer.setAddress( "广东省深圳市5");

    CustomerMapper customerMapper=session.getMapper(CustomerMapper. class);
    customerMapper.insertCustomer(customer);
    System.out.println(customer.getId());

    Orders orders1= new Orders();
    orders1.setCode( "code__5_1");
    orders1.setCustomerId(customer.getId());

    Orders orders2= new Orders();
    orders2.setCode( "code__5_2");
    orders2.setCustomerId(customer.getId());

    Orders orders3= new Orders();
    orders3.setCode( "code__5_3");
    orders3.setCustomerId(customer.getId());

    OrdersMapper ordersMapper=session.getMapper(OrdersMapper. class);
    ordersMapper.insertOrders(orders1);
    ordersMapper.insertOrders(orders2);
    ordersMapper.insertOrders(orders3);

    session.commit();
  }


  @Test
   public void testGetOrdersManyToOne(){
    OrdersMapper ordersMapper=session.getMapper(OrdersMapper. class);
    List<Orders> list=ordersMapper.getOrdersById(5);
     for( int i=0;i<list.size();i++){
      Orders orders=list.get(i);
      Customer customer=orders.getCustomer();
      System.out.println(orders.getId()+ "\t"+orders.getCode()+ "\t"+orders.getCustomerId());
      System.out.println( "\t \t--:"+customer.getId()+ "\t"+customer.getCname());
    }
    session.commit();
  }


  @Test
   public void testGetCustomerOneToMany(){
    CustomerMapper customerMapper=session.getMapper(CustomerMapper. class);
    Customer customer=customerMapper.getCustomer(5);
    List<Orders> orders=customer.getOrders();
    System.out.println(customer.getId()+ "\t"+customer.getCname()+ "\t"+customer.getPostcode()+ "\t"+customer.getAddress());
     for( int i=0;i<orders.size();i++){
      Orders order=orders.get(i);
      System.out.println( "\t \t --:"+order.getId()+ "\t"+order.getCode()+ "\t"+order.getCustomerId());
    }
    session.commit();
  }

  @After
   public void after(){
    session.close();
  }
}

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