Mybatis 一对多(OneToOne)关系映射

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 > 
    <!--  changes from the defaults for testing --> 
     < 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(); 
  } 
} 

本文出自 “李新博客” 博客，请务必保留此出处http://kinglixing.blog.51cto.com/3421535/709738