Hibernate的Hello World！

一、创建Java工程，新建Lib文件夹，加入Hibernate和数据库（如MySql、Oracle、SqlServer等）的Jar包

二、创建 hibernate.cfg.xml 文件，并配置，配置项如下：

 <?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">root</property>
         <property name="connection.password"></property>
         <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
         <property name="connection.url">jdbc:mysql:///mis</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.MySQL5Dialect</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/mcs/hibernate/helloworld/News.hbm.xml" />

     </session-factory>

 </hibernate-configuration>

三、新建News实体类并根据实体类创建对应的 hbm.xml文件

1、News实体明细如下：

 package com.mcs.hibernate.helloworld;

 import java.util.Date;

 public class News {

     private Integer id; // field
     private String title;
     private String author;

     private Date date;

     public Integer getId() { // property
         return 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
     }

     @Override
     public String toString() {
         return "News [id=" + id + ", title=" + title + ", author=" + author + ", date=" + date + "]";
     }

 }

2、News.hbm.xml明细如下：

 <?xml version="1.0"?>
 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 <!-- Generated -- :: by Hibernate Tools 3.5..Final -->
 <hibernate-mapping>
     <class name="com.mcs.hibernate.helloworld.News" table="NEWS">
         <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" type="java.lang.String">
             <column name="TITLE" />
         </property>
         <property name="author" type="java.lang.String">
             <column name="AUTHOR" />
         </property>
         <property name="date" type="java.util.Date">
             <column name="DATE" />
         </property>
     </class>
 </hibernate-mapping>

四、创建Junit测试类，并写下如下代码，测试新增数据与查询数据

 package com.mcs.hibernate.helloworld;

 import java.sql.Date;

 import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.Transaction;
 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
 import org.hibernate.cfg.Configuration;
 import org.hibernate.service.ServiceRegistry;
 import org.junit.Test;

 public class HibernateTest {

     @Test
     public 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();

         // 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 StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();

         /* ServiceRegistryBuilder已废弃 */
         /*
          * 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", "mcs", new Date(new java.util.Date().getTime()));
         session.save(news);

         //News news2 = (News) session.get(News.class, 1);
         //System.out.println(news2);

         // 5. 提交事务
         transaction.commit();

         // 6. 关闭 Session
         session.close();

         // 7. 关闭 SessionFactory 对象
         sessionFactory.close();
     }

 }

建议在Test测试类中如下写法：

 private SessionFactory sessionFactory;
     private Session session;
     private Transaction transaction;

     @Before
     public void init() {
         Configuration configuration = new Configuration().configure();

         ServiceRegistry serviceRegistry =
                 new StandardServiceRegistryBuilder().applySettings(configuration.getProperties())
                                                     .build();

         sessionFactory = configuration.buildSessionFactory(serviceRegistry);
         session = sessionFactory.openSession();
         transaction = session.beginTransaction();
     }

     @After
     public void destory() {
         transaction.commit();
         session.close();
         sessionFactory.close();
     }

     @Test
     public void test() {
         System.out.println("test...");
     }