Person类：
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package com.bjsxt.hibernate;
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
@Entitypublic class Person {
private Integer id;
private String name;
private Group1 group1;
@ManyToOne(cascade={CascadeType.MERGE,CascadeType.PERSIST,CascadeType.REFRESH})
public Group1 getGroup1() {
return group1;
}
public void setGroup1(Group1 group1) {
this.group1 = group1;
}
@Id
@GeneratedValue
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
} |
Group1类(数据库中group是关键字，也可以做一个映射)：
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package com.bjsxt.hibernate;
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
@Entitypublic class Group1 {
private Integer id;
private String name;
private List<Person> persons;
@OneToMany(mappedBy="group1",fetch=FetchType.EAGER,cascade={CascadeType.MERGE,CascadeType.REFRESH,CascadeType.REMOVE})
public List<Person> getPersons() {
return persons;
}
public void setPersons(List<Person> persons) {
this.persons = persons;
}
@Id
@GeneratedValue
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
} |
测试类：
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package com.bjsxt.hibernate;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.junit.Test;
public class TestPerson_group {
private static SessionFactory sessionFactory;
@Test
public void testAddPerson(){
sessionFactory=new AnnotationConfiguration().configure().buildSessionFactory();
Person person1=new Person();
person1.setName("person1");
Person person2=new Person();
person2.setName("person2");
Group1 group1=new Group1();
group1.setName("group1");
List<Person> persons=new ArrayList<Person>();
persons.add(person1);
persons.add(person2);
person1.setGroup1(group1);
person2.setGroup1(group1);
group1.setPersons(persons);
Session session=sessionFactory.getCurrentSession();
session.beginTransaction();
session.persist(group1);
session.getTransaction().commit();
}
@Test
public void deleteGroup1(){
sessionFactory=new AnnotationConfiguration().configure().buildSessionFactory();
Session session=sessionFactory.getCurrentSession();
session.beginTransaction();
Group1 group1=(Group1) session.get(Group1.class, 1);
List<Person> persons=group1.getPersons();
Iterator<Person> iterator=persons.iterator();
if(iterator.hasNext()){
Person person=iterator.next();
System.out.println(person.getName());
person.setGroup1(null);
}
session.update(group1);
/*
* 一定要先update一下group1，
* 将group1的每一个user的group设置为null，同步到数据库,否则group1对应于person的关联关系没有打破*/
group1.setPersons(null);
session.delete(group1);
session.getTransaction().commit();
System.out.println(group1.getName());
}
@Test
public void deleteUser(){
sessionFactory=new AnnotationConfiguration().configure().buildSessionFactory();
Session session=sessionFactory.getCurrentSession();
session.beginTransaction();
/*Person person=(Person) session.get(Person.class, 3);
person.setGroup1(null);
session.delete(person);*/
/*
* 或者直接写HQL删除*/
session.createQuery("delete from Person p where p.id=4").executeUpdate();
session.getTransaction().commit();
}
@Test
public void updatePerson(){
sessionFactory=new AnnotationConfiguration().configure().buildSessionFactory();
Session session=sessionFactory.getCurrentSession();
session.beginTransaction();
Person person=(Person) session.get(Person.class, 1);
person.setGroup1(null);
session.update(person);
session.getTransaction().commit();
}
@Test
public void updateGroup1(){
sessionFactory=new AnnotationConfiguration().configure().buildSessionFactory();
Session session=sessionFactory.getCurrentSession();
session.beginTransaction();
Group1 group1=(Group1) session.get(Group1.class, 1);
group1.setPersons(null);
session.update(group1);
session.getTransaction().commit();
}
}
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本文转自 matengbing 51CTO博客，原文链接:http://blog.51cto.com/matengbing/1879737