用MyEclipse开发Hibernate入门实例
http://developer.51cto.com 2009-06-30 14:02 佚名 百度博客 我要评论(0)
本文提供的Hibernate入门实例使用MyEclipse开发。文章从设置环境到最后的测试都介绍的十分详细。
以下为一个Hibernate入门实例，使用MyEclipse开发。
一、环境
1.eclipse 3.2.2
2.myeclipse 5.1.1
3.jdk 1.5
二、简要说明
数据库为mysql
在mysql中建立一个test数据库,建立cat表
CREATE TABLE `cat` (
`cat_id` varchar(32) NOT NULL,
`name` varchar(16) NOT NULL,
`sex` varchar(1) default NULL,
`weight` float(9,3) default NULL,
PRIMARY KEY (`cat_id`)
)
三、步骤
1.导入包的准备工作
a.新建java project.建立包example
在它下面编写类Cat.java
package example;
public class Cat implements java.io.Serializable {
// Fields
private String catId;
private String name;
private String sex;
private Float weight;
// Constructors
/** default constructor */
public Cat() {
}
/** minimal constructor */
public Cat(String name) {
this.name = name;
}
/** full constructor */
public Cat(String name, String sex, Float weight) {
this.name = name;
this.sex = sex;
this.weight = weight;
}
// Property accessors
public String getCatId() {
return this.catId;
}
public void setCatId(String catId) {
this.catId = catId;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return this.sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Float getWeight() {
return this.weight;
}
public void setWeight(Float weight) {
this.weight = weight;
}
}
同样在此包下面编写Cat.hbm.xml
< ?xml version="1.0" encoding="utf-8"?>
< !DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
< !--
Mapping file autogenerated by MyEclipse - Hibernate Tools
-->
< hibernate-mapping>
< class name="example.Cat" table="cat" catalog="testhibernate">
< id name="catId" type="java.lang.String">
< column name="cat_id" length="32" />
< generator class="uuid.hex">< /generator>
< /id>
< property name="name" type="java.lang.String">
< column name="name" length="16" not-null="true" />
< /property>
< property name="sex" type="java.lang.String">
< column name="sex" length="1" />
< /property>
< property name="weight" type="java.lang.Float">
< column name="weight" precision="9" scale="3" />
< /property>
< /class>
< /hibernate-mapping>
b.在工程的src里面加入一个包，用来存放将要生成的HibernateSessionFactory。包名如（example.util）。
导入hibernate生成的代码:
package example.util;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;
/**
* Configures and provides access to Hibernate sessions, tied to the
* current thread of execution. Follows the Thread Local Session
* pattern, see {@link http://hibernate.org/42.html }.
*/
public class HibernateSessionFactory {
/**
* Location of hibernate.cfg.xml file.
* Location should be on the classpath as Hibernate uses
* #resourceAsStream style lookup for its configuration file.
* The default classpath location of the hibernate config file is
* in the default package. Use #setConfigFile() to update
* the location of the configuration file for the current session.
*/
private static String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";
private static final ThreadLocal< Session> threadLocal = new ThreadLocal< Session>();
private static Configuration configuration = new Configuration();
private static org.hibernate.SessionFactory sessionFactory;
private static String configFile = CONFIG_FILE_LOCATION;
private HibernateSessionFactory() {
}
/**
* Returns the ThreadLocal Session instance. Lazy initialize
* the < code>SessionFactory< /code> if needed.
*
* @return Session
* @throws HibernateException
*/
public static Session getSession() throws HibernateException {
Session session = (Session) threadLocal.get();
if (session == null || !session.isOpen()) {
if (sessionFactory == null) {
rebuildSessionFactory();
}
session = (sessionFactory != null) ? sessionFactory.openSession()
: null;
threadLocal.set(session);
}
return session;
}
/**
* Rebuild hibernate session factory
*
*/
public static void rebuildSessionFactory() {
try {
configuration.configure(configFile);
sessionFactory = configuration.buildSessionFactory();
} catch (Exception e) {
System.err
.println("%%%% Error Creating SessionFactory %%%%");
e.printStackTrace();
}
}
/**
* Close the single hibernate session instance.
*
* @throws HibernateException
*/
public static void closeSession() throws HibernateException {
Session session = (Session) threadLocal.get();
threadLocal.set(null);
if (session != null) {
session.close();
}
}
/**
* return session factory
*
*/
public static org.hibernate.SessionFactory getSessionFactory() {
return sessionFactory;
}
/**
* return session factory
*
* session factory will be rebuilded in the next call
*/
public static void setConfigFile(String configFile) {
HibernateSessionFactory.configFile = configFile;
sessionFactory = null;
}
/**
* return hibernate configuration
*
*/
public static Configuration getConfiguration() {
return configuration;
}
}
对工程名点鼠标右键。选择myeclipse->add hibernate capabicities。
在弹出的窗口选择中Hibernate 3.0 Core Libraries和Hibernate 3.0 Advanced Support Libraries
下面选中Copy checked Library Jars to project folder and add to build-path。点击下一步。
c.默认（hibernate cofig file），下一步。
d.选中User JDBC driver
connect url: jdbc:mysql://localhost:3306/test
Driver class: org.gjt.mm.mysql.Driver
username: root
password: ******
Dialect: mysql
e.在第一行包选择里面，选择在前面第二大步建的包如（example）。点击完成。
f.弹出的画面中 选择properties的add按钮。在Property中加入show_sql，Value中加入true。点确定
保存设置。在mappings中点add加入前面建立的Cat.hbm.xml。最后生成的hibernate.cfg.xml文件如下
< ?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">
< !-- Generated by MyEclipse Hibernate Tools. -->
< hibernate-configuration>
< session-factory>
< property name="connection.username">root< /property>
< property name="connection.url">
jdbc:mysql://localhost:3306/testhibernate
< /property>
< property name="dialect">
org.hibernate.dialect.MySQLDialect
< /property>
< property name="connection.password">123456< /property>
< property name="connection.driver_class">
org.gjt.mm.mysql.Driver
< /property>
< property name="show_sql">true< /property>
< mapping resource="example/Cat.hbm.xml" />
< /session-factory>
< /hibernate-configuration>
3.测试 新建包test 在其中建立测试文件TestHibernate.java
package test;
import java.util.Iterator;
import java.util.List;
import example.*;
import example.util.*;
import org.hibernate.Session;
import org.hibernate.Transaction;
public class TestHibernate {
Session session=null;
Transaction tx=null;
public static void main(String[] args) {
TestHibernate th=new TestHibernate();
List cl=th.getAllCats();
if(cl!=null){
Iterator it=cl.iterator();
while(it.hasNext()){
Cat cat=(Cat)it.next();
System.out.println("catID:"+cat.getCatId()+"name:"+cat.getName()+"sex:"+cat.getSex());
}
}
}
public List getAllCats(){
session=HibernateSessionFactory.getSession();
List catlist=null;
try{
tx=session.beginTransaction();
catlist=session.createQuery("from Cat").list();
return catlist;
}catch(Exception ex){
System.err.println(ex.getMessage());
return null;
}finally{
HibernateSessionFactory.closeSession();
}
}
}
这个用MyEclipse开发的Hibernate入门实例，学习起来并不算难。