从读Hibernate的手册开始了学习Hibernate的历程。
《与猫同乐》－－－－乐的有些尴尬，因为在99％时，测试用了普通Java类，长时间滞留不前，把我的猫忘在门外了
１、配置数据源。
在Tomcat５中，修改conf\tomcat-users.xml文件，加入<user username="admin" password="admin" roles="admin"/>。启动Tomcat，进入管理页面，添加数据源，最终有如下信息加入项目的配置文件中：
<Resource name="jdbc/quickstart" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/quickstart">
<parameter>
<name>maxWait</name>
<value>5000</value>
</parameter>
<parameter>
<name>maxActive</name>
<value>4</value>
</parameter>
<parameter>
<name>password</name>
<value>secret</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:mysql://localhost/test</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.Driver</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>2</value>
</parameter>
<parameter>
<name>username</name>
<value>quickstart</value>
</parameter>
</ResourceParams>
２、添加Hibernate库
把所需的库加入类路径中，或是项目Lib中
３、编写hibernate.cfg.xml文件，置于项目编译后的根目录下（在Eclipse或其他IDE中，放在源文件根目录下即可），内容类似下示：
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration
PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="connection.datasource">java:comp/env/jdbc/quickstart</property>
<property name="show_sql">false</property>
<property name="dialect">net.sf.hibernate.dialect.PostgreSQLDialect</property>
<!-- Mapping files -->
<mapping resource="Cat.hbm.xml"/>
</session-factory>
</hibernate-configuration>
４、编写相应的映射类和配置文件，并放在同一目录下，例如：
package net.sf.hibernate.examples.quickstart;
public class Cat {
private String id;
private String name;
private char sex;
private float weight;
public Cat() {
}
public String getId() {
return id;
}
private void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public char getSex() {
return sex;
}
public void setSex(char sex) {
this.sex = sex;
}
public float getWeight() {
return weight;
}
public void setWeight(float weight) {
this.weight = weight;
}
}
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
<class name="net.sf.hibernate.examples.quickstart.Cat" table="CAT">
<!-- A 32 hex character is our surrogate key. It's automatically
generated by Hibernate with the UUID pattern. -->
<id name="id" type="string" unsaved-value="null" >
<column name="CAT_ID" sql-type="char(32)" not-null="true"/>
<generator class="uuid.hex"/>
</id>
<!-- A cat has to have a name, but it shouldn' be too long. -->
<property name="name">
<column name="NAME" length="16" not-null="true"/>
</property>
<property name="sex"/>
<property name="weight"/>
</class>
</hibernate-mapping>
*５、编写自定义SessionFactory类，例如：（此为Hibernate自带的示例）
HibernateUtil.java
package net.sf.hibernate.examples.quickstart;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import net.sf.hibernate.HibernateException;
import net.sf.hibernate.Session;
import net.sf.hibernate.SessionFactory;
import net.sf.hibernate.cfg.Configuration;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class HibernateUtil {
private static Log log = LogFactory.getLog(HibernateUtil.class);
private static final SessionFactory sessionFactory;
static {
try {
// Create the SessionFactory
sessionFactory = new Configuration().configure().buildSessionFactory();
} catch (Throwable ex) {
log.error("Initial SessionFactory creation failed.", ex);
throw new ExceptionInInitializerError(ex);
}
}
public static final ThreadLocal session = new ThreadLocal();
public static Session currentSession() throws HibernateException {
Session s = (Session) session.get();
// Open a new Session, if this Thread has none yet
if (s == null) {
s = sessionFactory.openSession();
session.set(s);
}
return s;
}
public static void closeSession() throws HibernateException {
Session s = (Session) session.get();
session.set(null);
if (s != null)
s.close();
}
}
６、编写测试Jsp或Serverlet，注意，这里是在Tomcat环境下，不能用普通Java类，示例Jsp：
<%@ page contentType="text/html;charset=GBK"%>
<%@ page import="net.sf.hibernate.Session"%>
<%@ page import="net.sf.hibernate.HibernateException"%>
<%@ page import="net.sf.hibernate.Transaction"%>
<%@ page import="net.sf.hibernate.examples.quickstart.Cat"%>
<%@ page import="net.sf.hibernate.examples.quickstart.HibernateUtil"%>
<html>
<body>
<hr>
<%
try{
Session ssession;
ssession = HibernateUtil.currentSession();
Transaction tx= ssession.beginTransaction();
Cat princess = new Cat();
princess.setName("Princess");
princess.setSex('F');
princess.setWeight(7.4f);
ssession.save(princess);
tx.commit();
HibernateUtil.closeSession();
}catch(HibernateException e){
}
%>
<hr>
</body>
</html>
