Hibernate - Quick Start

参考：Hibernate 5.0 http://docs.jboss.org/hibernate/orm/5.0/quickstart/html/

hibernate.cfg.xml

<?xml version=‘1.0‘ encoding=‘utf-8‘?>
<!--
  ~ Hibernate, Relational Persistence for Idiomatic Java
  ~
  ~ License: GNU Lesser General Public License (LGPL), version 2.1 or later.
  ~ See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
  -->
<!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>

        <!-- 数据库连接配置 -->
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="connection.url">jdbc:oracle:thin:@127.0.0.1:1521:xe</property>
        <property name="connection.username">myname</property>
        <property name="connection.password">mypassword</property>

        <!-- 内置的数据库连接池配置（不推荐使用内置的数据库连接池） -->
        <property name="connection.pool_size">1</property>

        <!-- SQL方言配置 -->
        <property name="dialect">org.hibernate.dialect.OracleDialect</property>

        <!-- 不设二级缓存 -->
        <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

        <!-- 打印SQL到标准输出 -->
        <property name="show_sql">true</property>

        <!-- create：启动时删除旧表重建新表 -->　　　　 <!-- create-drop：同上，不过关闭Hibernate时会删除表 -->　　　　 <!-- update：启动时验证表，若不一致会更新表 -->　　　　 <!-- validate：启动时验证表，若不一致抛异常，不会更新表（推荐） -->
        <property name="hbm2ddl.auto">create</property>

　　　　 <!-- 使用XML映射实体到数据库 -->
        <mapping resource="org/hibernate/tutorial/hbm/Event.hbm.xml"/>

　　　　 <!-- 使用注解映射实体到数据库 -->        <mapping class="org.hibernate.tutorial.annotations.Event"/>

    </session-factory>

</hibernate-configuration>

Java实体类

1. 使用标准JavaBean中对属性的传统命名方式，并有相应的getter和setter方法，属性私有

2. 无参的构造方法

Classname.hbm.xml

<?xml version="1.0"?>

<!--
  ~ Hibernate, Relational Persistence for Idiomatic Java
  ~
  ~ License: GNU Lesser General Public License (LGPL), version 2.1 or later.
  ~ See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
  -->
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.elenore.entity.hbm">

    <class name="Event" table="EVENTS">
        <id name="id" column="EVENT_ID">
            <generator class="increment"/>
        </id>
        <property name="date" type="timestamp" column="EVENT_DATE"/>　　　　 <!-- 不写type，则默认和声明的属性类型的默认匹配类型一样 -->　　　　 <!-- 不写column，则默认和name值一样 -->　　　　 <!-- 考虑到启动性能，应该显示说明属性的匹配类型（因为hibernate的自动匹配是通过反射机制） -->
        <property name="title"/>
    </class>

</hibernate-mapping>

使用注解映射

@Entity
@Table( name = "EVENTS" )
public class Event {
    private Long id;

    private String title;
    private Date date;

    public Event() {
        // this form used by Hibernate
    }

    public Event(String title, Date date) {
        // for application use, to create new events
        this.title = title;
        this.date = date;
    }

    @Id
    @GeneratedValue(generator="increment")
    @GenericGenerator(name="increment", strategy = "increment")
    public Long getId() {
        return id;
    }

    private void setId(Long id) {
        this.id = id;
    }

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "EVENT_DATE")
    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

     public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

Hibernate启动

protected void setUp() throws Exception {
        // SessionFactory在一个应用中只会被创建一次
        final StandardServiceRegistry registry = new StandardServiceRegistryBuilder()
         　　　　.configure() // 从hibernate.cfg.xml解析配置
                .build();
        try {
            sessionFactory = new MetadataSources( registry ).buildMetadata().buildSessionFactory();
        }
        catch (Exception e) {
            // registry会被SessionFactory自动销毁
            // 但是如果在创建SessionFactory时有异常，则需要手动销毁
            StandardServiceRegistryBuilder.destroy( registry );
        }
}

Hibernate使用

// 插入Session session = sessionFactory.openSession();
session.beginTransaction();
session.save( new Event( "Our very first event!", new Date() ) );
session.save( new Event( "A follow up event", new Date() ) );
session.getTransaction().commit();
session.close();

// 查询
session = sessionFactory.openSession();
session.beginTransaction();
List result = session.createQuery( "from Event" ).list();
for ( Event event : (List<Event>) result ) {
        System.out.println( "Event (" + event.getDate() + ") : " + event.getTitle() );
}
session.getTransaction().commit();
session.close();