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 2015-10-27 11:34:41 by Hibernate Tools 3.5.0.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...");
    }