hibernate.cfg.xml配置（Oracle+c3p0）

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说明：数据库：Oracle10g；连接池：c3p0

结构：

一、配置hibernate.cfg.xml

<?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">

<!-- c3p0连接池 -->
<hibernate-configuration>

<session-factory>
        <!-- 显示实际操作数据库时的SQL -->
        <property name="show_sql">true</property>
        <!-- SQL方言，这边设定的是Oracle -->
        <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>
        <!--驱动程序:Oracle数据库的配置 -->
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <!-- JDBC URL -->
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:myorcl</property>
        <!-- 数据库用户名 -->
        <property name="connection.username">scott</property>
        <!-- 数据库密码 -->
        <property name="connection.password">root</property>
        <!-- 指定连接池里最小连接数 -->
        <property name="hibernate.cp30.minsize">5</property>
        <!-- 指定连接池里的最大连接数 -->
        <property name="hibernate.c3p0.maxsize">20</property>
        <!-- 指定连接池里的超时时常 -->
        <property name="hibernate.cp30.timeout">1800</property>
        <!-- 指定连接池里最大缓存多少个Statement对象 -->
        <property name="hibernate.cp30.max_statements">50</property>
        <!-- 根据需要自动创建数据库表 -->
        <property name="hbm2ddl.auto">update</property>
        
        <!-- 对象与数据库表格映像文件 -->
       <mapping resource="com/chen/vo/News.hbm.xml"/>

    </session-factory>

</hibernate-configuration>

二、配置News.hbm.xml

说明：由于连接的数据库是Oracle，所有这里指定了序列：seq_news，如果设置<generator class="native"/>，则在插入数据时Hibernate默认会去查找Oracle中的hibernate_sequence序列（默认序列）。

<?xml version="1.0" encoding="utf-8"?>
<!-- 指定Hibernate映射文件的DTD信息 -->
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- hibernate-mapping是映射文件的根源素 -->
<hibernate-mapping>
<!-- 每个class对应一个持久化对象 -->
<class name="com.chen.vo.News" table="news_table">
<!-- id元素定义持久化类的标识属性 -->
<id name="id">
<generator class="sequence">
<param name="sequence">seq_news</param>
</generator>
</id>
<!-- property元素定义常规属性 -->
<property name="title"/>
<property name="content"/>
</class>
</hibernate-mapping>

三、创建vo

package com.chen.vo;

public class News
{
   //消息类的标识属性
   private Integer id;
   //消息标题
   private String title;
   //消息内容
   private String content;
   //id属性的setter和getter方法
   public void setId(Integer id)
   {
       this.id=id;
   }
   public Integer getId()
   {
       return this.id;
   }
   //title属性的setter和getter方法
   public void setTitle(String title)
   {
       this.title=title;
   }
   public String getTitle()
   { 
       return this.title; 
   }
   //content 属性的setter和getter方法
   public void setContent(String content)
   {
       this.content=content;
   }
   public String getContent()
   {
       return this.content;
   }
}

四、创建测试类

package com.chen.vo;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

public class NewsManager {
    public static void main(String[] args) throws Exception
       {
          //实例化configuration
          Configuration conf =new Configuration().configure();
          //以Configuration创建SessionFactory.注：buildSessionFactory方法已过时，不过仍可以获取SessionFactory。
//          SessionFactory sf=conf.buildSessionFactory();
          //采用ServiceRegistry获取SessionFactory
          StandardServiceRegistryBuilder serviceRegistryBuilder = new StandardServiceRegistryBuilder();  
          ServiceRegistry serviceRegistry = serviceRegistryBuilder.applySettings(conf.getProperties()).build(); 
          SessionFactory sf = conf.buildSessionFactory(serviceRegistry); 
          //创建session
          Session sess = sf.openSession(); 
          //开始事物 
          Transaction tx = sess.beginTransaction();
          //创建消息实例
          News n=new News();
          //设置消息标题和消息内容
          /**
           * Oracle插入数据说明：
           * 1.在News.hbm.xml中设置<generator class="native"/>
           * 连接Oracle，默认序列（Default.sequence）为hibernate_sequence
           * 使用native时Hibernate默认会去查找Oracle中的hibernate_sequence序列,所以插入数据时无需设置id。
           * 2.在News.hbm.xml中设置指定序列：
           * <generator class="sequence">
                <param name="sequence">seq_news</param>
             </generator>
           * Hibernate会按照序列seq_news创建新数据。
           */
          n.setTitle("title2");
          n.setContent("content2");
          //保存消息
          sess.save(n);
          //提交事务
          tx.commit();
          //关闭Session
          sess.close();
          sf.close();
       }

}

测试结果：

五、创建junit测试类、HibernateSessionFactory，通过session实现增、删、查、改

1.创建HibernateSessionFactory

package com.chen.utils;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

public class HibernateSessionFactory {
    private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
    //private static String configfile = "/hibernate.cfg.xml";
    private static Configuration configuration = new Configuration().configure();
    private static SessionFactory sessionFactory;

    static {
        try {
            StandardServiceRegistryBuilder serviceRegistryBuilder = new StandardServiceRegistryBuilder();  
            ServiceRegistry serviceRegistry = serviceRegistryBuilder.applySettings(configuration.getProperties()).build(); 
            sessionFactory = configuration.buildSessionFactory(serviceRegistry); 
        } catch (HibernateException e) {
            e.printStackTrace();
        }
    }

    private HibernateSessionFactory() {
    }

    public static Session getSession() {
        Session session = (Session) threadLocal.get();

        if (session == null || !session.isOpen()) {
            session = (sessionFactory != null) ? sessionFactory.openSession()
                    : null;
            threadLocal.set(session);
        }

        return session;
    }

    public static void closeSesssion() {
        Session session = threadLocal.get();
        threadLocal.set(null);
        if (session != null) {
            session.close();
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public static void setSessionFactory(SessionFactory sessionFactory) {
        HibernateSessionFactory.sessionFactory = sessionFactory;
    }

    public static Configuration getConfiguration() {
        return configuration;
    }

    public static void setConfiguration(Configuration configuration) {
        HibernateSessionFactory.configuration = configuration;
    }
}

2.在测试类进行测试

package com.chen.test;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;

import com.chen.utils.HibernateSessionFactory;
import com.chen.vo.News;

public class HibernateTest {
    //获取session
    @Test
    public void sessionTest(){
        Session session = HibernateSessionFactory.getSession();
        System.out.println(session);
    }
    //查询News的列表信息
    @Test
    public void listNews(){
        Session session = HibernateSessionFactory.getSession();
        Query query = session.createQuery("from News");
        List<?> list = query.list();
        System.out.println(list);
    }
    //通过id查询指定的News
    @Test
    public void findById(){
        Session session = HibernateSessionFactory.getSession();
        Query query = session.createQuery("from News where id=?");
        //设置参数
        query.setParameter(0, 1);
        //单值检索
        News n = (News) query.uniqueResult();
        System.out.println(n);
    }
    //添加News
    @Test
    public void saveNews(){
        Session session = HibernateSessionFactory.getSession();
        Transaction tx = session.beginTransaction();
        News n=new News();
        n.setTitle("title3");
        n.setContent("content3");
        session.saveOrUpdate(n);;
        tx.commit();
        session.close();
    }
    //修改News
    @Test
    public void updateNews(){
        Session session = HibernateSessionFactory.getSession();
        //先获取指定id的News
        Query query = session.createQuery("from News where id=?");
        query.setParameter(0, 5);
        News n = (News) query.uniqueResult();
        //再进行修改
        Transaction tx = session.beginTransaction();
        n.setContent("update_content5");
        session.saveOrUpdate(n);
        tx.commit();
        session.close();
        System.out.println(n);
    }
    //删除News
    @Test
    public void deteleNews(){
        Session session = HibernateSessionFactory.getSession();
        Query query = session.createQuery("from News where id=?");
        query.setParameter(0, 4);
        News n = (News) query.uniqueResult();
        Transaction tx = session.beginTransaction();
        session.delete(n);
        tx.commit();
        session.close();
    }

}

小结：“查”的实现是通过查询hql语句实现的。

附：Oracle创建序列seq_news及相应的自动增长触发器

create sequence seq_news;

CREATE OR REPLACE TRIGGER "SCOTT"."trigger_news" 
   before insert on "SCOTT"."NEWS_TABLE"
   for each row
begin
   if inserting then
      if :NEW."ID" is null then
         select seq_news.nextval into :NEW."ID" from dual;
      end if;
   end if;
end;
/
ALTER TRIGGER "SCOTT"."trigger_news" ENABLE;