[Solved] HibernateException: Access to DialectResolutionInfo cannot be null when ‘hibernate.dialect’

最新推荐文章于 2023-05-22 13:43:05 发布

转载最新推荐文章于 2023-05-22 13:43:05 发布 · 890 阅读

本文介绍了一位开发者在使用Hibernate 4.3.5.Final创建基本应用时遇到的AccesstoDialectResolutionInfocannotbenullwhen'hibernate.dialect'notset异常，并分享了详细的解决方案。

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I was following Hibernate Official Documentation to create a basic hibernate application with version 4.3.5.Final and when I executed the application, I get hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set even though all the configuration seemed fine to me.

It took me long time to solve the problem and it turned out to be with the way SessionFactoryinstance was getting created. My utility class to create SessionFactory instance was like below.

package com.journaldev.hibernate.util;

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

public class SessionFactoryUtil {

	private static SessionFactory sessionFactory;
	
	private static SessionFactory buildSessionFactory() {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
       	SessionFactory sessionFactory = new Configuration().configure("hibernate.cfg.xml")
        				.buildSessionFactory(new StandardServiceRegistryBuilder().build());
        	
            return sessionFactory;
        }
        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() {
		if(sessionFactory == null) sessionFactory = buildSessionFactory();
        return sessionFactory;
    }
}

And I was getting following stack trace:

May 07, 2014 7:11:59 PM org.hibernate.cfg.Configuration getConfigurationInputStream
INFO: HHH000040: Configuration resource: hibernate.cfg.xml
May 07, 2014 7:12:00 PM org.hibernate.cfg.Configuration addResource
INFO: HHH000221: Reading mappings from resource: employee.hbm.xml
May 07, 2014 7:12:00 PM org.hibernate.cfg.Configuration doConfigure
INFO: HHH000041: Configured SessionFactory: null
May 07, 2014 7:12:00 PM org.hibernate.engine.jdbc.connections.internal.ConnectionProviderInitiator initiateService
WARN: HHH000181: No appropriate connection provider encountered, assuming application will be supplying connections
Initial SessionFactory creation failed.org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
Exception in thread "main" java.lang.NullPointerException
	at com.journaldev.hibernate.main.HibernateMain.main(HibernateMain.java:38)

From the logs its clear that Configuration class was able to find the hibernate configuration file and it has hibernate.dialect defined, so the exception was not making any sense.

After some research and debugging, I was able to fix it. The part that is missing in the official documentation is that we need to apply the configuration properties toStandardServiceRegistryBuilder. When I changed the utility class to below, everything worked like a charm.

package com.journaldev.hibernate.util;

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

public class SessionFactoryUtil {

	private static SessionFactory sessionFactory;
	
	private static SessionFactory buildSessionFactory() {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
        	Configuration configuration = new Configuration();
        	configuration.configure("hibernate.cfg.xml");
        	System.out.println("Hibernate Configuration loaded");
        	
        	//apply configuration property settings to StandardServiceRegistryBuilder
        	ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
        	System.out.println("Hibernate serviceRegistry created");
        	
        	SessionFactory sessionFactory = configuration
        						.buildSessionFactory(serviceRegistry);
        	
            return sessionFactory;
        }
        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() {
		if(sessionFactory == null) sessionFactory = buildSessionFactory();
        return sessionFactory;
    }
}

Hibernate is still evolving and every version comes with a lot of changes and I feel that documentation part is lagging. I hope this will help someone fixing the issue rather than wasting a lot of time debugging.