跨向Hibernate（一）

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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。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：

 
 
   
      maxWait
      5000
   
   
      maxActive
      4
   
   
      password
      secret
   
   
      url
      jdbc:mysql://localhost/test
   
   
      driverClassName
      com.mysql.jdbc.Driver
   
   
      maxIdle
      2
   
   
      username
      quickstart
   
 

 

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：

    PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
    " http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">

 

 

   

 

        java:comp/env/jdbc/quickstart
        false
        net.sf.hibernate.dialect.PostgreSQLDialect

 

       
       

 

   

 

 

 

 

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;
    }

 

}

 

    PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
    " http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

 

 

   

 

       
       
           
           
       

 

       
       
           
       

 

       

 

       

 

   

 

*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"%>

 

 

---

<%
          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){
            }
           
%>

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