Hibernate实战——事件机制中的事件系统

╰+哭是因爲堅強的太久メ 2021-07-25 01:28 360阅读 0赞

**一 配置**

<?xml version="1.0" encoding="GBK"?>
    
    <!DOCTYPE hibernate-configuration PUBLIC
         "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
         "http://www.hibernate.org/dtd/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/hibernate</property>
               
               <property name="connection.username">root</property>
               
               <property name="connection.password">32147</property>
               
               <property  name="hibernate.c3p0.max_size">20</property>
               
               <property name="hibernate.c3p0.min_size">1</property>
               
               <property  name="hibernate.c3p0.timeout">5000</property>
               
               <property  name="hibernate.c3p0.max_statements">100</property>
               <property  name="hibernate.c3p0.idle_test_period">3000</property>
               <property  name="hibernate.c3p0.acquire_increment">2</property>
               <property  name="hibernate.c3p0.validate">true</property>
               
               <property  name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
               
               <property name="hbm2ddl.auto">update</property>
               
               <property name="show_sql">true</property>
               
               <property name="hibernate.format_sql">true</property>
               
               <property  name="hibernate.current_session_context_class">thread</property>
               
               <mapping class="org.crazyit.app.domain.User"/>
         </session-factory>
    </hibernate-configuration>

**二 PO**

package org.crazyit.app.domain;
    
    import java.util.*;
    
    import javax.persistence.*;
    
    @Entity
    @Table(name="user_inf")
    
    public class User
    {
        @Id @Column(name="user_id")
        @GeneratedValue(strategy=GenerationType.IDENTITY)
        private Integer id;
        private String name;
        private int age;
        private String nationality;
    
        // 无参数的构造器
        public User()
        {
        }
        // 初始化全部成员变量的构造器
        public User(Integer id , String name , int age , String nationality)
        {
            this.id = id;
            this.name = name;
            this.age = age;
            this.nationality = nationality;
        }
    
        // id的setter和getter方法
        public void setId(Integer id)
        {
            this.id = id;
        }
        public Integer getId()
        {
            return this.id;
        }
    
        // name的setter和getter方法
        public void setName(String name)
        {
            this.name = name;
        }
        public String getName()
        {
            return this.name;
        }
    
        // age的setter和getter方法
        public void setAge(int age)
        {
            this.age = age;
        }
        public int getAge()
        {
            return this.age;
        }
    
        // nationality的setter和getter方法
        public void setNationality(String nationality)
        {
            this.nationality = nationality;
        }
        public String getNationality()
        {
            return this.nationality;
        }
    
    }

**三 监听器**

1 MyLoadListener

package org.crazyit.common.hibernate;
    
    import org.hibernate.event.internal.DefaultLoadEventListener;
    import org.hibernate.HibernateException;
    import org.hibernate.event.spi.LoadEvent;
    import org.hibernate.event.spi.LoadEventListener;
    
    
    public class MyLoadListener extends DefaultLoadEventListener
    {
        // 在LoadEventListener接口仅仅定义了这个方法
        public void onLoad(LoadEvent event,
            LoadEventListener.LoadType loadType)
            throws HibernateException
        {
            System.out.println("自定义的load事件");
            System.out.println(event.getEntityClassName()
                + "==========" + event.getEntityId());
            super.onLoad(event, loadType);
        }
    }

2 MySaveListener

package org.crazyit.common.hibernate;
    
    import java.io.Serializable;
    
    import org.hibernate.event.internal.DefaultSaveEventListener;
    import org.hibernate.HibernateException;
    import org.hibernate.event.spi.SaveOrUpdateEvent;
    import org.hibernate.event.spi.LoadEventListener;
    
    
    // Hibernate的默认事件监听器类都被声明成non-final的了。
    public class MySaveListener extends DefaultSaveEventListener
    {
        public Serializable performSaveOrUpdate(SaveOrUpdateEvent event)
        {
            System.out.println("自定义的save事件");
            System.out.println(event.getObject());
            return super.performSaveOrUpdate(event);
        }
    }

**四 测试**

package lee;
    
    import org.hibernate.*;
    import org.hibernate.internal.*;
    import org.hibernate.cfg.*;
    import org.hibernate.service.*;
    import org.hibernate.event.spi.*;
    import org.hibernate.event.service.spi.*;
    import org.hibernate.boot.registry.*;
    
    import java.util.*;
    
    import org.crazyit.app.domain.*;
    import org.crazyit.common.hibernate.*;
    
    public class UserManager
    {
        static Configuration cfg = new Configuration()
            // 加载hibernate.cfg.xml配置文件
            .configure();
        // 以Configuration实例来创建SessionFactory实例
        static ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
            .applySettings(cfg.getProperties()).build();
        static SessionFactory sf = cfg.buildSessionFactory(serviceRegistry);
        static{
            // 获取该SessionFactory的事件监听器注册器
            EventListenerRegistry elr = ((SessionFactoryImpl)sf)
                .getServiceRegistry().getService(EventListenerRegistry.class);
            // 使用用户指定的拦截器序列代替系统默认的save拦截器序列
            elr.setListeners(EventType.SAVE, MySaveListener.class);
            // 使用用户指定的拦截器序列代替系统默认的load拦截器序列
            elr.setListeners(EventType.LOAD, MyLoadListener.class);
        }
        public static void main(String[] args)
        {
            UserManager mgr = new UserManager();
            mgr.testUser();
            sf.close();
        }
        private void testUser()
        {
            Session session = sf.getCurrentSession();
            Transaction tx = session.beginTransaction();
            // 创建一个User对象
            User u1 = new User();
            // 设置基本属性
            u1.setName("crazyit.org");
            u1.setAge(30);
            u1.setNationality("china");
            // 保存一个User对象
            session.save(u1);
            // 装载一个已有的User对象
            User u = (User)session.get(User.class , 1);
            // 改变属性
            u.setName("疯狂Java联盟");
            tx.commit();
        }
    }

**五 测试结果**

自定义的save事件
    org.crazyit.app.domain.User@7c214cc0
    Hibernate:
        insert
        into
            user_inf
            (age, name, nationality)
        values
            (?, ?, ?)
    自定义的load事件
    org.crazyit.app.domain.User==========1
    Hibernate:
        select
            user0_.user_id as user_id1_0_0_,
            user0_.age as age2_0_0_,
            user0_.name as name3_0_0_,
            user0_.nationality as national4_0_0_
        from
            user_inf user0_
        where
            user0_.user_id=?