[Hibernate系列—] 1. 下载与试用Hibernate(MySQL与Oracle 配置)

Hibernate是什么？

对于学习Java的开发者来说，这个问题不应该是一个问题。

一句话： Hibernate 是针对Java环境的对象/关系映射的解决方案，或者说是第三方库。

它的作用就是省去了开发者花在Java类对应数据库表，Java数据对应到SQL数据类型的时间。减少了开发者花在处理SQL和JDBC的时间。

在开发角度来说，最大的不同是：

使用 JDBC开发时，基本还是组出SQL，通过JDBC  API来执行SQL。

而使用 Hibernate，对Java 对象进行save 或其他操作，就会自动保存到数据库中，也就是使用Hibernate  更体现了面向对象的概念， 当然, hibernae  的好处远不止于此。

如何获取hibernate

下载：

到hibernate 的官方网站下载。目前的最新版是 4.3.5.Final， 下载地址：

http://sourceforge.net/projects/hibernate/files/hibernate4/4.3.5.Final/hibernate-release-4.3.5.Final.zip/download

也可以到 ：

https://onedrive.live.com/redir?resid=5B4EDBCD9EF1AB6B!191&authkey=!ABaYyXT8zlybvig&ithint=file%2c.zip

下载

目录结构

解压下载后的 zip 档， 解压后的目录结构如下：

documentation -- 存放了hibernate 的快速入门文档，开发手册，API文档等英文文档

project -- 存放了一些测试的例子

lib - 存放了jar 包，里面又分成了几个子目录。

   lib/required -- 一些核心包， 开发时需要把这个目录下的所有文件放到项目的classpath 下

   lib/jpa  - 主要是hibernate-entitymanager.jar , 依赖于  required里的jar 档。主要是JPA用的（Java Persistence API）

   lib/events

   lib/Optional

在Eclipse中建立测试项目

这里使用mysql 数据库测试， 要下载一个 Mysql JDBC 的jar 档。

到 http://dev.mysql.com/downloads/connector/j/ 下载

下载页面如下：

不过下载这个， 需要登录oralce 网站。

也可以直接到 https://onedrive.live.com/redir?resid=5B4EDBCD9EF1AB6B!193&authkey=!AHJhNgziTxpiRGg&ithint=file%2c.jar 下载

在Eclipse 中建立一个Java Project

1.  建立lib 目录， 将 hibernate  lib\required 目录下所有的jar 当和mysql jdbc 档（mysql-connector-java-5.1.30-bin.jar）放入lib 目录。 并导入

2.  在src 根目录下建立 hibernate.cfg.xml， 内容如下：

<?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://localhost:3306/test</property>        <property name="connection.username">root</property>        <property name="connection.password">123456</property>        <!-- JDBC connection pool (use the built-in) -->        <property name="connection.pool_size">1</property>        <!-- SQL dialect-->        <property name="dialect">org.hibernate.dialect.MySQLDialect</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>         <!-- Names the annotated entity class -->        <mapping resource="com/oscar999/Usr.hbm.xml"/>    </session-factory></hibernate-configuration>

3. 在src 下， 新建 com.oscar999 包， 加入Usr.hbm.xml， 内容如下：

<?xml version="1.0"?><!--  ~ Hibernate, Relational Persistence for Idiomatic Java  ~  ~ Copyright (c) 2010, Red Hat Inc. or third-party contributors as  ~ indicated by the @author tags or express copyright attribution  ~ statements applied by the authors.  All third-party contributions are  ~ distributed under license by Red Hat Inc.  ~  ~ This copyrighted material is made available to anyone wishing to use, modify,  ~ copy, or redistribute it subject to the terms and conditions of the GNU  ~ Lesser General Public License, as published by the Free Software Foundation.  ~  ~ This program is distributed in the hope that it will be useful,  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY  ~ or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License  ~ for more details.  ~  ~ You should have received a copy of the GNU Lesser General Public License  ~ along with this distribution; if not, write to:  ~ Free Software Foundation, Inc.  ~ 51 Franklin Street, Fifth Floor  ~ Boston, MA  02110-1301  USA  --><!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.oscar999">    <class name="Usr" table="D_USER">         <id name="emp_id" column="EMP_ID">            <generator class="assigned"/>        </id><property name="user_name" column="USER_NAME"/><property name="email_addr" column="EMAIL_ADDR"/><property name="location" column="LOCATION"/><property name="title" column="TITLE"/><property name="mobile" column="MOBILE"/><property name="extnum" column="EXTNUM"/>        <property name="hire_date" type="timestamp" column="HIRE_DATE"/>        <property name="resign_date" type="timestamp" column="RESIGN_DATE"/>        <property name="active" column="ACTIVE"/>    </class></hibernate-mapping>

4. 在同包目录下， 加入  Usr.java

package com.oscar999;import java.util.Date;public class Usr {private String emp_id;private String user_name;private String email_addr;private String location;private String title;private String mobile;private String extnum;private Date hire_date;private Date resign_date;private String active;public Usr() {// this form used by Hibernate}public Usr(String emp_id) {this.emp_id = emp_id;}public String getEmp_id() {return emp_id;}public void setEmp_id(String emp_id) {this.emp_id = emp_id;}public String getUser_name() {return user_name;}public void setUser_name(String user_name) {this.user_name = user_name;}public String getEmail_addr() {return email_addr;}public void setEmail_addr(String email_addr) {this.email_addr = email_addr;}public String getLocation() {return location;}public void setLocation(String location) {this.location = location;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public String getMobile() {return mobile;}public void setMobile(String mobile) {this.mobile = mobile;}public String getExtnum() {return extnum;}public void setExtnum(String extnum) {this.extnum = extnum;}public Date getHire_date() {return hire_date;}public void setHire_date(Date hire_date) {this.hire_date = hire_date;}public Date getResign_date() {return resign_date;}public void setResign_date(Date resign_date) {this.resign_date = resign_date;}public String getActive() {return active;}public void setActive(String active) {this.active = active;}}

5. 接下来就是写测试文件了 TestMySQL.java

/* * @author: oscar999 * @Date:2014-6-3 * Copyright (c) oscar999. All rights reserved. */package com.oscar999;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.boot.registry.StandardServiceRegistryBuilder;import org.hibernate.cfg.Configuration;import org.hibernate.service.ServiceRegistry;/** * <description> *  * @see * @see *  * @version 0.1, 2014-6-3 * @author oscar999 * @since JDK1.5 */public class TestMySQL {public static void main(String[] args) {Configuration configuration = new Configuration().configure();ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);Session session = sessionFactory.openSession();session.beginTransaction();session.save(new Usr("oscar999"));session.getTransaction().commit();session.close();sessionFactory.close();}}

用workbench 查看db 的话， 就可以看到结果了。

再贴一下， 如果是oracle, hibernate.cfg.xml 如何配置：

<?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">oracle.jdbc.driver.OracleDriver</property>        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:yoursid</property>        <property name="connection.username">yourusername</property>        <property name="connection.password">yourpassword</property>        <!-- JDBC connection pool (use the built-in) -->        <property name="connection.pool_size">1</property>        <!-- SQL dialect-->        <property name="dialect">org.hibernate.dialect.OracleDialect</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>         <!-- Names the annotated entity class -->        <mapping resource="com/oscar999/Usr.hbm.xml"/>    </session-factory></hibernate-configuration>