环境和结构和上一章节一样，不细述。。直接看代码

 

实例条件：Person 和 Address ，一个人用于多个房子，人可以改变房子，房子也可以变动人

 

Person类：

package cn.dao;

 

import java.io.Serializable;

import java.util.HashSet; import java.util.Set;

import javax.persistence.CascadeType;

import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.OneToMany; import javax.persistence.Table;

 

 

 

@Table(name = "person") public class Person implements Serializable{    private Long id;    private String name;    private String defaultAddress;    private Set<Address> as = new HashSet<Address>();

 

 @Id

 @Column(name = "id")  @GeneratedValue(strategy = GenerationType.IDENTITY)  public Long getId() {   return id;  }

 

 public void setId(Long id) {

  this.id = id;  }

 

 @Column(name = "name")

 public String getName() {   return name;  }

 

 public void setName(String name) {

  this.name = name;  }    @Column(name = "defaultAddress")  public String getDefaultAddress() {   return defaultAddress;  }

 

 public void setDefaultAddress(String defaultAddress) {

  this.defaultAddress = defaultAddress;  }    @OneToMany (fetch = FetchType.LAZY,cascade = { CascadeType.ALL },mappedBy = "person")  public Set<Address> getAs() {   return as;  }

 

 public void setAs(Set<Address> as) {

  this.as = as;  }    

 

}

 

Address类：

package cn.dao;

 

import java.io.Serializable;

 

import javax.persistence.Column;

import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.Table;

 

import com.sun.istack.internal.NotNull;

 

@Entity

@Table(name = "address") public class Address implements Serializable{    private Long id;    private String name;    private Person person;

 

 @Id

 @GeneratedValue(strategy = GenerationType.IDENTITY)  public Long getId() {   return id;  }

 

 public void setId(Long id) {

  this.id = id;  }    @Column(name = "name")  public String getName() {   return name;  }

 

 public void setName(String name) {

  this.name = name;  }    @ManyToOne  @NotNull  @JoinColumn(name = "personId")  public Person getPerson() {   return person;  }

 

 public void setPerson(Person person) {

  this.person = person;  }     }

 

主类：OneToManyDouble：

package cn.test;

 

import java.util.HashSet;

import java.util.Set;

 

import org.hibernate.Session; import org.hibernate.Transaction; import org.junit.Test;

 

import cn.dao.Address;

import cn.dao.Person; import cn.utils.HibernateUtil;

 

/**

 * 一对多的双向关联  * @author hasee  *  */ public class OneToManyDouble {    public static void main(String[] args){   editFromAddress();  }    public static void save(){   Session session = HibernateUtil.getSession();   org.hibernate.Transaction transaction = session.beginTransaction();   Person person = new Person();   person.setName("Lucy");   person.setDefaultAddress("BeiJing");//默认地址   Set<Address> as = new HashSet<Address>();//旗下有许多房子   Address addressOne = new Address();   addressOne.setName("ShangHai");   addressOne.setPerson(person);   as.add(addressOne);   Address addressTwo = new Address();   addressTwo.setName("ShenZhen");   addressTwo.setPerson(person);   as.add(addressTwo);   person.setAs(as);   session.save(person);   transaction.commit();   HibernateUtil.closeSession();  }    public static void delete(){   Session session = HibernateUtil.getSession();   Transaction transaction = session.beginTransaction();   //删除一个人的同时删除其关联的住址   Person person = (Person) session.get(Person.class, 5L);   session.delete(person);   transaction.commit();   //后台打印查看sql语句发现效率很低，可以直接根据ID删除Address表的信息，不必关联查询   HibernateUtil.closeSession();  }    public static void edit(){   Session session = HibernateUtil.getSession();   Transaction transaction = session.beginTransaction();   //根据ID获取到人的信息,修改Address表的住址   Person person = (Person) session.get(Person.class, 6L);   Set<Address> as = person.getAs();   for (Address address : as) {    if(address.getName().equals("ShangHai")){     address.setName("ShangHai_change");    }   }   session.update(person);   transaction.commit();   HibernateUtil.closeSession();  }    //根据Address操作Person表  public static void saveFromAddress(){   Session session = HibernateUtil.getSession();   Transaction transaction = session.beginTransaction();   Address address = new Address();   address.setName("newCity");   Person person = (Person) session.get(Person.class, 6L);//新的住址属于已经存在的一个人的(也可以新建一个Person)   address.setPerson(person);   session.save(address);//这里是保存Person还是Address呢？----> 结果是：Address <-----   transaction.commit();   HibernateUtil.closeSession();     }    public static void deleteFromAddress(){   Session session = HibernateUtil.getSession();   Transaction transaction = session.beginTransaction();   Address address = (Address) session.get(Address.class, 12L);   session.delete(address);//对Person是没什么影响的   transaction.commit();   HibernateUtil.closeSession();  }    public static void editFromAddress(){   Session session = HibernateUtil.getSession();   Transaction transaction = session.beginTransaction();   Address address = (Address) session.get(Address.class, 13L);   Person person = address.getPerson();   person.setName("Mike");//直接修改掉主人   session.update(address);   transaction.commit();   HibernateUtil.closeSession();  }   }