使用 XML 进行 Hibernate 多对一映射

2024 年 8 月 29 日 | 阅读 2 分钟

在多对一映射中，多个属性可以只引用一个属性。

在本例中，每个员工只有一个公司地址，并且一个地址属于多个员工。在这里，我们将使用 XML 执行多对一映射。

1) 一对一映射的持久化类

有两个持久化类 Employee.java 和 Address.java。 Employee 类包含 Address 类引用，反之亦然。

Employee.java

package com.javatpoint;  
  
public class Employee {  
private int employeeId;  
private String name,email;  
private Address address;  
//setters and getters  
}  

Address.java

package com.javatpoint;  
  
public class Address {  
private int addressId;  
private String addressLine1,city,state,country;  
private int pincode;  
private Employee employee;  
//setters and getters  
}

2) 持久化类的映射文件

两个映射文件是 employee.hbm.xml 和 address.hbm.xml。

employee.hbm.xml

<?xml version='1.0' encoding='UTF-8'?>  
<!DOCTYPE hibernate-mapping PUBLIC  
          "-//Hibernate/Hibernate Mapping DTD 5.3//EN"  
          "http://hibernate.sourceforge.net/hibernate-mapping-5.3.dtd">  
  
          <hibernate-mapping>  
          <class name="com.javatpoint.Employee" table="emp22">  
          <id name="employeeId">  
          <generator class="increment"></generator>  
          </id>  
          <property name="name"></property>  
          <property name="email"></property>  
            
          <many-to-one name="address" cascade="all"></many-to-one>  
          </class>  
            
          </hibernate-mapping> 

address.hbm.xml

<?xml version='1.0' encoding='UTF-8'?>  
<!DOCTYPE hibernate-mapping PUBLIC  
          "-//Hibernate/Hibernate Mapping DTD 5.3//EN"  
          "http://hibernate.sourceforge.net/hibernate-mapping-5.3.dtd">  
  
          <hibernate-mapping>  
          <class name="com.javatpoint.Address" table="address22">  
          <id name="addressId">  
          <generator class="increment"></generator>  
          </id>  
          <property name="addressLine1"></property>  
          <property name="city"></property>  
          <property name="state"></property>  
          <property name="country"></property>  
          <property name="pincode"></property>  
          </class>  
          </hibernate-mapping>  

3) 配置文件

此文件包含有关数据库和映射文件的信息。

<?xml version='1.0' encoding='UTF-8'?>  
<!DOCTYPE hibernate-configuration PUBLIC  
          "-//Hibernate/Hibernate Configuration DTD 5.3//EN"  
          "http://hibernate.sourceforge.net/hibernate-configuration-5.3.dtd">  
   
<hibernate-configuration>  
  
    <session-factory>  
        <property name="hbm2ddl.auto">update</property>  
        <property name="dialect">org.hibernate.dialect.Oracle9Dialect</property>  
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:xe</property>  
        <property name="connection.username">system</property>  
        <property name="connection.password">jtp</property>  
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>  
    <mapping resource="employee.hbm.xml"/>  
    <mapping resource="address.hbm.xml"/>  
    </session-factory>  
  
</hibernate-configuration>  

4) 用于存储和获取数据的用户类

Store.java

package com.javatpoint;  

import org.hibernate.*;
import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;  
  
public class Store {  
public static void main(String[] args) {  
	
	StandardServiceRegistry ssr=new StandardServiceRegistryBuilder().configure("hibernate.cfg.xml").build();
	Metadata meta=new MetadataSources(ssr).getMetadataBuilder().build();
	
	SessionFactory factory=meta.getSessionFactoryBuilder().build();
	Session session=factory.openSession();
	
    Transaction t=session.beginTransaction();  
      
    Employee e1=new Employee();  
    e1.setName("Ravi Malik");  
    e1.setEmail("ravi@gmail.com");  
    
    Employee e2=new Employee();
    e2.setName("Anuj Verma");
    e2.setEmail("anuj@gmail.com");
      
    Address address1=new Address();  
    address1.setAddressLine1("G-13,Sector 3");  
    address1.setCity("Noida");  
    address1.setState("UP");  
    address1.setCountry("India");  
    address1.setPincode(201301);  
      
    e1.setAddress(address1);  
    e2.setAddress(address1);

    session.persist(e1);  
    session.persist(e2);
    t.commit();  
      
    session.close();  
    System.out.println("success");  
}  
}  

输出

Fetch.java

package com.javatpoint;  
import java.util.Iterator;  
import java.util.List;

import javax.persistence.TypedQuery;  
import org.hibernate.Session;  
import org.hibernate.SessionFactory;
import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder; 
  
public class Fetch {  
public static void main(String[] args) {  
	StandardServiceRegistry ssr=new StandardServiceRegistryBuilder().configure("hibernate.cfg.xml").build();
	Metadata meta=new MetadataSources(ssr).getMetadataBuilder().build();
	
	SessionFactory factory=meta.getSessionFactoryBuilder().build();
	Session session=factory.openSession();
      
    TypedQuery query=session.createQuery("from Employee e");  
    List<Employee> list=query.getResultList(); 
      
    Iterator<Employee> itr=list.iterator();  
    while(itr.hasNext()){  
     Employee emp=itr.next();  
     System.out.println(emp.getEmployeeId()+" "+emp.getName()+" "+emp.getEmail());  
     Address address=emp.getAddress();  
     System.out.println(address.getAddressLine1()+" "+address.getCity()+" "+  
        address.getState()+" "+address.getCountry()+" "+address.getPincode());  
    }  
  
    session.close();  
    System.out.println("success");  
}  
}  

输出

下载

下载此Hibernate示例

下一个主题使用注解的 Hibernate 多对一

使用 XML 进行 Hibernate 多对一映射

1) 一对一映射的持久化类

Employee.java

Address.java

2) 持久化类的映射文件

employee.hbm.xml

address.hbm.xml

3) 配置文件

4) 用于存储和获取数据的用户类

Store.java

输出

Fetch.java

输出

下载

联系信息

关注我们

教程

面试题

在线编译器

Python

Java

.Net Framework

AI, ML and Data Science

Cloud Technology

B.Tech and MCA

Web Technology

PHP

Software Testing

Technical Interview

Java Interview

Python

Web Interview

Database Interview

B.Tech / MCA

Important Interview

Software Testing Interview

Company Interviews

Online Compilers

Multiple Choice Questions

Hibernate 教程

Hibernate 与 Eclipse

Hibernate 示例

Hibernate Log4j

继承映射

Hibernate 映射

事务管理

HQL

HCQL

命名查询

Hibernate 缓存

二级缓存

集成

其他

Hibernate 面试

使用 XML 进行 Hibernate 多对一映射

1) 一对一映射的持久化类

Employee.java

Address.java

2) 持久化类的映射文件

employee.hbm.xml

address.hbm.xml

3) 配置文件

4) 用于存储和获取数据的用户类

Store.java

输出

Fetch.java

输出

下载

相关帖子

集合映射

一对多注解

一对多 XML

映射 List

双向

多对一注解

映射 Bag

延迟加载集合

映射 Map

一对一注解

订阅 Tpoint Tech

联系信息

关注我们

教程

面试题

在线编译器