Hibernate 一对多注解 实例

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

关于mappedby关键字 及一对多 更多的解释：

http://blog.csdn.net/z69183787/article/details/8197106

http://blog.csdn.net/z69183787/article/details/18615577