HibernateUtil Helper 修正

使用官方文档可能会出现 HibernateException: Access to DialectResolutionInfo cannot be null when ‘hibernate.dialect’ not set 的错误。因为它根本没去读配置文件。

官方版本 http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html/ch01.html#tutorial-firstapp-helpers

package org.hibernate.tutorial.util;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;

public class HibernateUtil {

    private static final SessionFactory sessionFactory = buildSessionFactory();

    private static SessionFactory buildSessionFactory() {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
            return new Configuration().configure().buildSessionFactory(
			    new StandardServiceRegistryBuilder().build() );
        }
        catch (Throwable ex) {
            // Make sure you log the exception, as it might be swallowed
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

}

该版本有点问题，并没有读取配置文件信息。更改后如下

package org.hibernate.tutorial.util;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.boot.registry.StandardServiceRegistry;

public class HibernateUtil {
    private static final SessionFactory sessionFactory = buildSessionFactory();
    
    private static SessionFactory buildSessionFactory(){
        try {
            Configuration configuration = new Configuration();
            configuration.configure("hibernate.cfg.xml");
            System.out.println("Hibernate Configuration loaded");
            
            StandardServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
            System.out.println("Hibernate serviceRegistry created");
            
            SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);
            
            return sessionFactory;
            
        } catch (Throwable ex) {
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }
    
    public static SessionFactory getSessionFactory(){
        return sessionFactory;
    }
}

原文转载自：http://www.journaldev.com/2897/solved-hibernateexception-access-to-dialectresolutioninfo-cannot-be-null-when-hibernate-dialect-not-set