吴裕雄--天生自然轻量级JAVA EE企业应用开发Struts2Sping4Hibernate整合开发学习笔记：Hibernate指定generated属性

<?xml version="1.0" encoding="GBK"?>
<project name="hibernate" basedir="." default="">
    <property name="src" value="src"/>
    <property name="dest" value="classes"/>

    <path id="classpath">
        <fileset dir="../../lib">
            <include name="**/*.jar"/>
        </fileset>
        <pathelement path="${dest}"/>
    </path>

    <target name="compile" description="Compile all source code">
        <delete dir="${dest}"/>
        <mkdir dir="${dest}"/>
        <copy todir="${dest}">
            <fileset dir="${src}">
                <exclude name="**/*.java"/>
            </fileset>        
        </copy>
        <javac destdir="${dest}" debug="true" includeantruntime="yes"
            deprecation="false" optimize="false" failonerror="true">
            <src path="${src}"/>
            <classpath refid="classpath"/>
            <compilerarg value="-Xlint:deprecation"/>
        </javac>
    </target>

    <target name="run" description="Run the main class" depends="compile">
        <java classname="lee.NewsManager" fork="yes" failonerror="true">
            <classpath refid="classpath"/>
        </java>
    </target>

</project>

drop database hibernate;
create database hibernate;
use hibernate;
create table news_inf
(
 id int auto_increment primary key,
 title varchar(255) not null,
 content varchar(255),
 full_content varchar(255)
);
DELIMITER |
create trigger t_full_content_gen BEFORE INSERT ON news_inf
    FOR EACH ROW BEGIN
        set new.full_content=concat(new.title,new.content);
    END;
|
DELIMITER ;

<?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>
        <!-- 指定连接数据库所用的驱动 -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <!-- 指定连接数据库的url，其中hibernate是本应用连接的数据库名 -->
        <property name="connection.url">jdbc:mysql://localhost/hibernate</property>
        <!-- 指定连接数据库的用户名 -->
        <property name="connection.username">root</property>
        <!-- 指定连接数据库的密码 -->
        <property name="connection.password">32147</property>
        <!-- 指定连接池里最大连接数 -->
        <property name="hibernate.c3p0.max_size">20</property>
        <!-- 指定连接池里最小连接数 -->
        <property name="hibernate.c3p0.min_size">1</property>
        <!-- 指定连接池里连接的超时时长 -->
        <property name="hibernate.c3p0.timeout">5000</property>
        <!-- 指定连接池里最大缓存多少个Statement对象 -->
        <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>
        <!-- 指定数据库方言 -->
        <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
        <!-- 根据需要自动创建数据表 -->
        <property name="hbm2ddl.auto">update</property><!--①-->
        <!-- 显示Hibernate持久化操作所生成的SQL -->
        <property name="show_sql">true</property>
        <!-- 将SQL脚本进行格式化后再输出 -->
        <property name="hibernate.format_sql">true</property>
        <!-- 罗列所有持久化类的类名 -->
        <mapping class="org.crazyit.app.domain.News"/>
    </session-factory>
</hibernate-configuration>

package org.crazyit.app.domain;

import javax.persistence.*;
import org.hibernate.annotations.Generated;
import org.hibernate.annotations.GenerationTime;
/**
 * Description:
 * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a>
 * <br/>Copyright (C), 2001-2016, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee kongyeeku@163.com
 * @version  1.0
 */
@Entity
@Table(name="news_inf")
public class News
{
    // 消息类的标识属性
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;
    // 消息标题
    private String title;
    // 消息内容
    private String content;
    // 指定@Generated的value为ALWAYS，表明该属性的值由数据库生成，
    // Hibernate会在每次执行insert、update时执行select语句来查询获取该属性的值
    @Generated(GenerationTime.ALWAYS)
    private String fullContent;

    // 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;
    }

    // fullContent的setter和getter方法
    public void setFullContent(String fullContent)
    {
        this.fullContent = fullContent;
    }
    public String getFullContent()
    {
        return this.fullContent;
    }
}

package lee;

import org.hibernate.*;
import org.hibernate.cfg.*;
import org.hibernate.service.*;
import org.hibernate.boot.registry.*;
import org.crazyit.app.domain.*;

/**
 * Description:
 * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a>
 * <br/>Copyright (C), 2001-2016, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee kongyeeku@163.com
 * @version  1.0
 */
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);
//        News n = (News)sess.get(News.class , 1);
//        // 输出fullContent值
//        System.out.println(n.getFullContent());
        // 提交事务
        tx.commit();
        // 关闭Session
        sess.close();
        sf.close();
    }
}