Hibernate3.3.2_关联关系的CRUD_Cascade_Fetch_1

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例子下载地址http://putaoputao.qupan.cc/7008003.html

一.存user

1.Group.java

package com.bjsxt.hibernate;import java.util.HashSet;import java.util.Set;import javax.persistence.CascadeType;import javax.persistence.Entity;import javax.persistence.FetchType;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.JoinColumn;import javax.persistence.OneToMany;import javax.persistence.Table;@Entity@Table(name="t_group")public class Group {private int id;private String name;private Set<User> users = new HashSet<User>();@Id@GeneratedValuepublic int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}@OneToMany(mappedBy="group",cascade={CascadeType.ALL})public Set<User> getUsers() {return users;}public void setUsers(Set<User> users) {this.users = users;}}

2.User.java 注解@ManyToOne(cascade={CascadeType.ALL})中CascadeType.ALL代表对一个对象操作也会影响关联的对象。

CascadeType.ALL和CascadeType.PERSIST和CascadeType.REMOVE最常用。

package com.bjsxt.hibernate;import javax.persistence.CascadeType;import javax.persistence.Entity;import javax.persistence.FetchType;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.ManyToOne;import javax.persistence.Table;@Entity@Table(name="t_user")public class User {private int id;private String name;private Group group;@ManyToOne(cascade={CascadeType.ALL})public Group getGroup() {return group;}public void setGroup(Group group) {this.group = group;}@Id@GeneratedValuepublic int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}}

3.hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?><!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"><hibernate-configuration> <session-factory> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost/gjl</property> <property name="connection.username">root</property> <property name="connection.password">wodemima</property> <property name="dialect">org.hibernate.dialect.MySQLDialect</property>   <property name="connection.pool_size">1</property>  <property name="current_session_context_class">thread</property>  <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>  <property name="show_sql">true</property> <property name="format_sql">true</property>   <mapping class="com.bjsxt.hibernate.Group"/><mapping class="com.bjsxt.hibernate.User"/> </session-factory></hibernate-configuration>

4.测试程序

HibernateORMappingTest

package test.com.bjsxt.hibernate;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.AnnotationConfiguration;import org.hibernate.tool.hbm2ddl.SchemaExport;import org.junit.AfterClass;import org.junit.BeforeClass;import org.junit.Test;import com.bjsxt.hibernate.Group;import com.bjsxt.hibernate.User;public class HibernateORMappingTest {private static SessionFactory sessionFactory;@BeforeClasspublic static void beforeClass() {new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();}@AfterClasspublic static void afterClass() {sessionFactory.close();}@Testpublic void testSaveUser() {User u = new User();u.setName("u1");Group g = new Group();g.setName("g1");u.setGroup(g);Session s = sessionFactory.getCurrentSession();s.beginTransaction();//s.save(g);s.save(u);s.getTransaction().commit();}@Testpublic void testSaveGroup() {User u1 = new User();u1.setName("u1");User u2 = new User();u2.setName("u2");Group g = new Group();g.setName("g1");g.getUsers().add(u1);g.getUsers().add(u2);u1.setGroup(g);u2.setGroup(g);Session s = sessionFactory.getCurrentSession();s.beginTransaction();//s.save(g);s.save(g);s.getTransaction().commit();}@Testpublic void testGetUser() {testSaveGroup();Session s = sessionFactory.getCurrentSession();s.beginTransaction();User u = (User)s.get(User.class, 1);s.getTransaction().commit();System.out.println(u.getGroup().getName());}@Testpublic void testLoadUser() {testSaveGroup();Session s = sessionFactory.getCurrentSession();s.beginTransaction();User u = (User)s.load(User.class, 1);System.out.println(u.getGroup().getName());s.getTransaction().commit();}@Testpublic void testDeleteUser() {testSaveGroup();Session s = sessionFactory.getCurrentSession();s.beginTransaction();//User u = (User)s.load(User.class, 1);//u.setGroup(null);//s.delete(u);s.createQuery("delete from User u where u.id = 1").executeUpdate();s.getTransaction().commit();}@Testpublic void testDeleteGroup() {testSaveGroup();Session s = sessionFactory.getCurrentSession();s.beginTransaction();//User u = (User)s.load(User.class, 1);//u.setGroup(null);//s.delete(u);Group g = (Group)s.load(Group.class, 1);s.delete(g);//s.createQuery("delete from User u where u.id = 1").executeUpdate();s.getTransaction().commit();}@Testpublic void testUpdateUser() {testSaveGroup();Session s = sessionFactory.getCurrentSession();s.beginTransaction();User u = (User)s.get(User.class, 1);s.getTransaction().commit();u.setName("user");u.getGroup().setName("group");Session s2 = sessionFactory.getCurrentSession();s2.beginTransaction();s2.update(u);s2.getTransaction().commit();}@Testpublic void testGetGroup() {testSaveGroup();Session s = sessionFactory.getCurrentSession();s.beginTransaction();Group g = (Group)s.get(Group.class, 1);s.getTransaction().commit();for(User u : g.getUsers()) {System.out.println(u.getName());}}@Testpublic void testSchemaExport() {new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);}public static void main(String[] args) {beforeClass();}}

二.存group

1.程序在上面找就是测试函数不同

三.注意

fetch用于查找同步，cascade用于增删改同步