Hibernate 初步

hibernate-release-4.1.6: 

http://downloads.sourceforge.net/project/hibernate/hibernate4/4.1.6.Final/hibernate-release-4.1.6.Final.zip?r=http%3A//sourceforge.net%2Fprojects%2Fhibernate%2Ffiles%2Fhibernate4%2F4.1.6.Final%2F&ts=1345636454&use_mirror=nchc

Hibernate configuration file

Hibernate配置文件: hibernate.cfg.xml

property:

connection.driver_class

connection.url

connection.username

connection.password

connection.pool_size : Hibernate内置连接池，不作为生产之用。

dialect

hbm2ddl.auto : ddl自动建表之用。

mapping:

resource : mapping file的路径。例: org/hibernate/tutorial/hbm/Event.hbm.xml

<?xml version='1.0' encoding='utf-8'?><!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>        <!-- Database connection settings -->        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>        <property name="connection.url">jdbc:mysql://127.0.0.1:3306/hibernate</property>        <property name="connection.username">root</property>        <property name="connection.password">root</property>        <!-- JDBC connection pool (use the built-in) -->        <property name="connection.pool_size">1</property>        <!-- SQL dialect         <property name="dialect">org.hibernate.dialect.H2Dialect</property>-->        <!-- Disable the second-level cache  -->        <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>        <!-- Echo all executed SQL to stdout -->        <property name="show_sql">true</property>        <!-- Drop and re-create the database schema on startup -->        <property name="hbm2ddl.auto">create</property>        <mapping resource="org/hibernate/tutorial/hbm/Event.hbm.xml"/>    </session-factory></hibernate-configuration>

Entity Java Class

实体Java类

JavaBean风格的类: getter, setter, 无参数constructor

Mapping File

EntityClassName.hbm.xml。例: Event.hbm.xml

class <-> table

id -> column : 定义主键。

property -> type, column : 这里的type是 Hibernate mapping types，用于转换Java类型和SQL类型。如果没写type，根据Java class的类型而定。

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"><hibernate-mapping package="org.hibernate.tutorial.hbm">    <class name="Event" table="EVENTS">        <id name="id" column="EVENT_ID">            <generator class="increment"/>        </id>        <property name="date" type="timestamp" column="EVENT_DATE"/>        <property name="title"/>    </class></hibernate-mapping>

示例代码:

package org.hibernate.tutorial.hbm;import java.util.Date;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.cfg.Configuration;public class HelloHibernate {private SessionFactory sessionFactory;public HelloHibernate() {init();}@SuppressWarnings("deprecation")private void init() {sessionFactory = new Configuration().configure().buildSessionFactory();}public void close() {sessionFactory.close();}public void create() {Session session = sessionFactory.openSession();Transaction transaction = session.beginTransaction();// Createsession.save(new Event("hello world1", new Date())); // id=1session.save(new Event("hello world2", new Date())); // id=2session.save(new Event("hello world3", new Date())); // id=3transaction.commit();session.close();}public void read() {Session session = sessionFactory.openSession();Transaction transaction = session.beginTransaction();// ReadEvent e = (Event) session.get(Event.class, 1L); // id=1if (e != null) {System.out.println("event 1 : " + e.getTitle() + " " + e.getDate());}transaction.commit();session.close();}public void update() {Session session = sessionFactory.openSession();Transaction transaction = session.beginTransaction();// UpdateEvent e = new Event();e.setId(2L);e.setTitle("updated");session.saveOrUpdate(e);transaction.commit();session.close();}public void delete() {Session session = sessionFactory.openSession();Transaction transaction = session.beginTransaction();// DeleteEvent e = new Event();e.setId(3L); // workssession.delete(e);// we *always* assume an instance with a null identifier or no// identifier property is unsaved!// Event e2 = new Event();// e2.setTitle("hello world"); //does not work. : isTransient// session.delete(e2);transaction.commit();session.close();}public static void main(String[] args) {HelloHibernate hello = new HelloHibernate();hello.create();hello.read();hello.update();hello.delete();hello.close();}}

Event:

package org.hibernate.tutorial.hbm;import java.util.Date;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 eventsthis.title = title;this.date = date;}public Long getId() {return id;}public void setId(Long id) {this.id = id;}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;}}

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