Hibernate实战——GenericGenerator注解

痛定思痛。 2021-07-24 22:09 1438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>
               
               <mapping class="org.crazyit.app.domain.News"/>
         </session-factory>
    </hibernate-configuration>

**二 PO**

package org.crazyit.app.domain;
    
    import javax.persistence.*;
    import org.hibernate.annotations.GenericGenerator;
    
    @Entity
    @Table(name="news_inf")
    public class News
    {
        // 消息类的标识属性
        @Id @Column(name="news_id")
        // 使用@GenericGenerator定义主键生成器。
        // 该主键生成器名为fk_hilo，使用Hibernate的hilo策略，
        @GenericGenerator(name="fk_hilo" , strategy="hilo")
        // 指定使用fk_hilo主键生成器
        @GeneratedValue(generator="fk_hilo")
        private Integer id;
        // 消息标题
        private String title;
        // 消息内容
        private String content;
    
        // id的setter和getter方法
        public void setId(Integer id)
        {
            this.id = id;
        }
        public Integer getId()
        {
            return this.id;
        }
    
        // title的setter和getter方法
        public void setTitle(String title)
        {
            this.title = title;
        }
        public String getTitle()
        {
            return this.title;
        }
    
        // content的setter和getter方法
        public void setContent(String content)
        {
            this.content = content;
        }
        public String getContent()
        {
            return this.content;
        }
    }

**三 测试**

package lee;
    
    import org.hibernate.*;
    import org.hibernate.cfg.*;
    import org.hibernate.service.*;
    import org.hibernate.boot.registry.*;
    import org.crazyit.app.domain.*;
    
    public class NewsManager
    {
        public static void main(String[] args)
            throws Exception
        {
            // 实例化Configuration，
            Configuration conf = new Configuration()
            // 不带参数的configure()方法默认加载hibernate.cfg.xml文件，
            // 如果传入abc.xml作为参数，则不再加载hibernate.cfg.xml，改为加载abc.xml
                .configure();
            ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
                .applySettings(conf.getProperties()).build();
            // 以Configuration实例创建SessionFactory实例
            SessionFactory sf = conf.buildSessionFactory(serviceRegistry);
            // 创建Session
            Session sess = sf.openSession();
            // 开始事务
            Transaction tx = sess.beginTransaction();
            // 创建消息对象
            News n = new News();
            // 设置消息标题和消息内容
            n.setTitle("疯狂Java联盟成立了");
            n.setContent("疯狂Java联盟成立了，"
                + "网站地址http://www.crazyit.org");
            // 保存消息
            sess.save(n);
            // 提交事务
            tx.commit();
            // 关闭Session
            sess.close();
            sf.close();
        }
    }

**四 测试效果**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70]: /images/20210724/f39d7da6b41b4f3f8e71dfcec799bc85.png