Hibernate 一对多注解 实例
Posted skinchqqhah
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了Hibernate 一对多注解 实例相关的知识，希望对你有一定的参考价值。
student：
/**
*
*/
package com.wonders.task.sample.bo;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;
/**
* @ClassName: Student
* @Description: TODO(这里用一句话描述这个类的作用)
* @author zhoushun
* @date 2014年2月27日 上午11:48:30
*
*/
@Entity
@Table(name="Z_STUDENT")
public class Student {
private String id;
private String name;
private Clazz clazz;
@Id
@GeneratedValue(generator="system-uuid")
@GenericGenerator(name="system-uuid", strategy = "uuid")
@Column(name = "ID")
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
@Column(name = "NAME", length = 500)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@ManyToOne(cascade={CascadeType.ALL})
@JoinColumn(name="class_id") //student类中对应外键的属性：classid
public Clazz getClazz() {
return clazz;
}
public void setClazz(Clazz clazz) {
this.clazz = clazz;
}
}
classes:
/**
*
*/
package com.wonders.task.sample.bo;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;
/**
* @ClassName: Clazz
* @Description: TODO(这里用一句话描述这个类的作用)
* @author zhoushun
* @date 2014年2月27日 上午11:48:47
*
*/
@Entity
@Table(name="Z_CLASS")
public class Clazz implements java.io.Serializable{
/**
*
*/
private static final long serialVersionUID = -6224738252966513441L;
private String id;
private String name;
private Set<Student> set;
@Id
@GeneratedValue(generator="system-uuid")
@GenericGenerator(name="system-uuid", strategy = "uuid")
@Column(name = "ID")
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
@Column(name = "NAME", length = 500)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany(cascade=CascadeType.ALL,mappedBy="clazz")
//@OneToMany(cascade=CascadeType.ALL,mappedBy="clazz",fetch=FetchType.EAGER) 关闭延迟加载。
public Set<Student> getSet() {
return set;
}
public void setSet(Set<Student> set) {
this.set = set;
}
}
main:
/**
*
*/
package com.wonders.task.sample.main;
import java.util.HashSet;
import java.util.Set;
import javax.annotation.Resource;
import org.hibernate.Hibernate;
import org.hibernate.Session;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Scope;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.orm.hibernate3.HibernateTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import com.wonders.schedule.util.SpringBeanUtil;
import com.wonders.task.sample.ITaskService;
import com.wonders.task.sample.bo.Clazz;
import com.wonders.task.sample.bo.Student;
/**
* @ClassName: TestMain
* @Description: TODO(这里用一句话描述这个类的作用)
* @author zhoushun
* @date 2014年2月27日 下午12:18:44
*
*/
@Transactional(propagation = Propagation.REQUIRED, rollbackFor = Exception.class)
/* 功能模块入口点，beanid即数据库配置中的name */
@Service("testMain")
@Scope("prototype")
public class TestMain {
private HibernateTemplate hibernateTemplate;
public HibernateTemplate getHibernateTemplate() {
return hibernateTemplate;
}
//注入hibernateTemplate
@Resource(name="hibernateTemplate")
public void setHibernateTemplate(HibernateTemplate hibernateTemplate) {
this.hibernateTemplate = hibernateTemplate;
}
public void test(){
Session session = this.getHibernateTemplate().getSessionFactory().getCurrentSession();
Clazz c2 = (Clazz) session.get(Clazz.class, "8a81a97c4471c661014471c669360002");
//Clazz c2 = (Clazz) main.getHibernateTemplate().get(Clazz.class, "8a81a97c4471c661014471c669360002");
Hibernate.initialize(c2.getSet());
System.out.println("11111111111111111111111");
//session.close();
Set<Student> sss = c2.getSet();
System.out.println("22222222222222222");
for(Student s: sss){
System.out.println(s.getName());
}
}
public static void main(String[] args){
ApplicationContext applicationContext = null;
String[] fileUrl = new String[]{"classpath*:applicationContext*.xml"};
applicationContext = new ClassPathXmlApplicationContext(fileUrl);
Student s1 = new Student();
Student s2 = new Student();
Clazz c1 = new Clazz();
c1.setName("1班");
s1.setName("z1");
s1.setClazz(c1);
s2.setName("z2");
s2.setClazz(c1);
Set<Student> set = new HashSet<Student>();
set.add(s1);set.add(s2);
c1.setSet(set);
TestMain main = (TestMain)SpringBeanUtil.getBean("testMain");
//main.getHibernateTemplate().save(c1);
// Session session = main.getHibernateTemplate().getSessionFactory().openSession();
// Clazz c2 = (Clazz) session.get(Clazz.class, "8a81a97c4471c661014471c669360002");
// //Clazz c2 = (Clazz) main.getHibernateTemplate().get(Clazz.class, "8a81a97c4471c661014471c669360002");
// Hibernate.initialize(c2.getSet());
//
// System.out.println("11111111111111111111111");
// session.close();
// Set<Student> sss = c2.getSet();
// System.out.println("22222222222222222");
// for(Student s: sss){
//
// System.out.println(s.getName());
// }
main.test();
//main.getHibernateTemplate().delete(c2);
}
}
级联保存
方法1：自动维护两表关系，mappedby 为被拥维护方，即对应的student为维护方
Student s1 = new Student();
Student s2 = new Student();
Clazz c1 = new Clazz();
c1.setName("1班");
s1.setName("z1");
s1.setClazz(c1);
s2.setName("z2");
s2.setClazz(c1);
TestMain main = (TestMain)SpringBeanUtil.getBean("testMain");
main.getHibernateTemplate().save(s1);
main.getHibernateTemplate().save(s2);
方法2：手动维护，两方都需要set对应对方的变量
Student s1 = new Student();
Student s2 = new Student();
Clazz c1 = new Clazz();
c1.setName("1班");
s1.setName("z1");
s1.setClazz(c1);
s2.setName("z2");
s2.setClazz(c1);
Set<Student> set = new HashSet<Student>();
set.add(s1);set.add(s2);
c1.setSet(set);
TestMain main = (TestMain)SpringBeanUtil.getBean("testMain");
main.getHibernateTemplate().save(c1);
关于延迟加载：
http://blog.csdn.net/z69183787/article/details/20049409
http://blog.csdn.net/z69183787/article/details/17136627
再分享一下我老师大神的人工智能教程吧。零基础！通俗易懂！风趣幽默！还带黄段子！希望你也加入到我们人工智能的队伍中来！https://blog.csdn.net/jiangjunshow
以上是关于Hibernate 一对多注解 实例的主要内容，如果未能解决你的问题，请参考以下文章