Mybatis 一对多(OneToOne)关系映射

淩亂°似流年 2022-06-14 02:38 273阅读 0赞

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();   
  \}   
\}