Hibernate_HelloWorld

@@@Session接口

session是应用程序与数据库之间交互操作的一个单线程对象，是hibernate运作中心。所有持久化对象必须在session管理下才可以进行持久化。此对象生命周期很短，Session对象有一个一级缓存，在显式flush之前，所有的持久层操作都缓存在session对象处。相当于JDBC的Connection。

1.新建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>    <!-- 配置连接数据库的基本信息 --><property name="connection.username">test</property><property name="connection.password">test</property><property name="connection.driver_class">com.mysql.jdbc.Driver</property><property name="connection.url">jdbc:mysql://localhost:3306/javbusdb?useUnicode=true&characterEncoding=utf8</property><!-- 配置 hibernate 的基本信息 --><!-- hibernate 所使用的数据库方言 --><property name="dialect">org.hibernate.dialect.MySQLInnoDBDialect</property><!-- 执行操作时是否在控制台打印 SQL --><property name="show_sql">true</property><!-- 是否对 SQL 进行格式化 --><property name="format_sql">true</property><!-- 指定自动生成数据表的策略 --><property name="hbm2ddl.auto">update</property><!-- 指定关联的 .hbm.xml 文件 --><mapping resource="com/atguigu/hibernate/helloworld/News.hbm.xml"/></session-factory></hibernate-configuration>

策略hbm2ddl.auto可选择参数：

create：每次连接都创建新标

update：表结构变化会更新表结构

create-drop:建完表关闭连接就会删除表

validate：启动时验证现有schema与你配置的hibernate是否一致，如果不一致就抛出异常，并不做更新

2.Bean映射文件

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping package="com.atguigu.hibernate.helloworld">    <class name="News" table="NEWS" dynamic-insert="true">            <id name="id" type="java.lang.Integer">            <column name="ID" />            <!-- 指定主键的生成方式, native: 使用数据库本地方式 -->            <generator class="native" />        </id>            <property name="title" not-null="true" unique="true"        index="news_index" length="50"        type="java.lang.String" column="TITLE" >        </property>                <property name="author" type="java.lang.String"        index="news_index">            <column name="AUTHOR" />        </property>                <property name="date" type="date">            <column name="DATE" />        </property>           </class>    </hibernate-mapping>

3.Bean结构

public class News {private Integer id; //fieldprivate String title;private String author;private String desc;//使用 title + "," + content 可以来描述当前的 News 记录. //即 title + "," + content 可以作为 News 的 desc 属性值private String content;private Blob picture;public Blob getPicture() {return picture;}public void setPicture(Blob picture) {this.picture = picture;}public String getContent() {return content;}public void setContent(String content) {this.content = content;}public String getDesc() {return desc;}public void setDesc(String desc) {this.desc = desc;}private Date date;public Integer getId() { //propertyreturn id;}public void setId(Integer id) {this.id = id;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public String getAuthor() {return author;}public void setAuthor(String author) {this.author = author;}public Date getDate() {return date;}public void setDate(Date date) {this.date = date;}public News(String title, String author, Date date) {super();this.title = title;this.author = author;this.date = date;}public News() {// TODO Auto-generated constructor stub}@Overridepublic String toString() {return "News [id=" + id + ", title=" + title + ", author=" + author+ ", date=" + date + "]";}}

4.测试用例

package com.atguigu.hibernate.helloworld;import java.sql.Date;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.cfg.Configuration;import org.hibernate.service.ServiceRegistry;import org.hibernate.service.ServiceRegistryBuilder;import org.junit.Test;public class HibernateTest {@Testpublic void test() {System.out.println("test...");//1. 创建一个 SessionFactory 对象SessionFactory sessionFactory = null;//1). 创建 Configuration 对象: 对应 hibernate 的基本配置信息和 对象关系映射信息Configuration configuration = new Configuration().configure(); //源码中默认关联根目录的hibernate.cfg.xml//4.0 之前这样创建//sessionFactory = configuration.buildSessionFactory();//2). 创建一个 ServiceRegistry 对象: hibernate 4.x 新添加的对象//hibernate 的任何配置和服务都需要在该对象中注册后才能有效.ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties())                            .buildServiceRegistry();//3).sessionFactory = configuration.buildSessionFactory(serviceRegistry);//2. 创建一个 Session 对象Session session = sessionFactory.openSession();//3. 开启事务Transaction transaction=session.beginTransaction();

//4. 执行保存操作News news = new News("Java12345", "HHCX", new Date(new java.util.Date().getTime()));session.save(news);//5. 提交事务 transaction.commit();//6. 关闭 Sessionsession.close();//7. 关闭 SessionFactory 对象sessionFactory.close();}}