为什么Hibernate Session第一次可以用，第二次就不可以呢？

[hawaii162162]

HibernateUtil代码

package common;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtil {

	private static final SessionFactory sessionFactory = buildSessionFactory();

	private static SessionFactory buildSessionFactory() {

		try {
			return new Configuration().configure().buildSessionFactory();
		}

		catch (Throwable ex) {

			System.err.println("Initial SessionFactory creation failed." + ex);
			throw new ExceptionInInitializerError(ex);
		}
	}

	public static SessionFactory getSessionFactory() {
		return sessionFactory;
	}

}

ExamInfoImpl代码

package service.impl;

import java.io.UnsupportedEncodingException;
import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;

import orm.exam_info;
import service.ExamInfo;


import common.HibernateUtil;

public class ExamInfoImpl extends HibernateUtil implements ExamInfo {

	/* (non-Javadoc)
	 * @see service.ExamInfo#addExamInfo(orm.exam_info)
	 */
	
	public void addExamInfo(exam_info examinfo) {
		Session ss =HibernateUtil.getSessionFactory().openSession();
		ss.beginTransaction();
		ss.save(examinfo);
		ss.getTransaction().commit();		
	}
	public List getExamInfo(){
		Session ss =HibernateUtil.getSessionFactory().openSession();
		List list=null;
		Query q = ss.createSQLQuery("select * from SYS_EXAM_INFO").addEntity(exam_info.class);
	    list = q.list();
		return list;
	}
	public String getExamInfoById(String id){
		Session ss =HibernateUtil.getSessionFactory().openSession();
		List list=null;
		StringBuilder sb = new StringBuilder();
		Query q = ss.createSQLQuery("select * from SYS_EXAM_INFO where exam_eid="+id).addEntity(exam_info.class);
		list = q.list();
		if(list!=null){
			exam_info obj = (exam_info) list.get(0);
			try {
				sb.append("[").append("{EXAM_EID:").append(obj.getEID()).append(",EXAM_ETIME:\"").append(obj.getETIME()).append("\",EXAM_MCOUNT:").append(obj.getMCOUNT()).append(",EXAM_MONEY:").append(obj.getMONEY()).append(",EXAM_NOWCOUNT:").append(obj.getNOWCOUNT()).append(",EXAM_OTHER:\"").append(new String(obj.getOTHER().getBytes("iso-8859-1"),"gb2312")).append("\"}").append("]");
			} catch (UnsupportedEncodingException e) {
				e.printStackTrace();
			}
		}
		return sb.toString();
		
	}
	   
	
	

}

代码逻辑上实现都没问题，问题是

当我第一次调用 ExamInfoImpl 的getExamInfoById方法的时候 第一次可以成功调用 但是第二次再用的时候就提示org.hibernate.SessionException: Session is closed!

项目中就只用了Hibernate，希望高手能给出问题的原因和解决的办法 谢谢

[japt88_115656292]

你代码应该没铁全，你找找看哪里把session关了，肯定就是不该关的时候关闭了session。。

[dw_595573]

ExamInfoImpl类干吗要继承HibernateUtils类 不懂
个人建议最好一个数据库操作对应一个session操作，而且这里只给了个方法 代码不全

[YOYOOOP]

HibernateUtil类的问题
在Hibernate给我们提供的一个sessionFactory类中，有如下的声明及使用：
private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();

public static void closeSession() throws HibernateException {
Session session = (Session) threadLocal.get();
threadLocal.set(null);

if (session != null) {
session.close();
}
}

从上面的代码应该可以看出.hibernate的session是取的当前线程中的.
而你自定义类中。只是关闭了session.而并未对当前线程做处理。
这样的话，会导致取到的session永远是关闭的.

如果我的理解有误，请高手纠正

[YOYOOOP]

1111

[YOYOOOP]

[java]111
[/java]

[lu76689614]

修改配置文件

在一对多 或多对多

后面加lazy="false"

[YOYOOOP]

dddd

[YOYOOOP]

供参考

package com.sideline.Hibernate;

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 SessionFactory {

    /** 
     * 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 SessionFactory() {
    }
	
	/**
     * 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) {
		SessionFactory.configFile = configFile;
		sessionFactory = null;
	}

	/**
     *  return hibernate configuration
     *
     */
	public static Configuration getConfiguration() {
		return configuration;
	}

}

[chooseforget]

有正解么。等。

[YeHuai1991]

　修改Hibernate配制文件将配制文件中的lazy属性设置为"false"

[renjianguokeivor]

[Quote=引用 11 楼 huai__ye 的回复:]
　修改Hibernate配制文件将配制文件中的lazy属性设置为"false"
[/Quote]
？？？？？？？？？？

[abckdt]

每个方法都要关闭session，像这样的：
public List getExamInfo(){
Session ss =HibernateUtil.getSessionFactory().openSession();
List list=null;
Query q = ss.createSQLQuery("select * from SYS_EXAM_INFO").addEntity(exam_info.class);
list = q.list();
ss.close();
return list;
}
你把方法里面都加下试下看，看还会不会报错