Question

嗨我正在使用eclipse这个hibernate更新。

我有这个配置：

<?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">
<hibernate-configuration>
 <session-factory>
  <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>

  <property name="hibernate.connection.url">jdbc:mysql://localhost:3306</property>

  <property name="hibernate.connection.username">root</property>

  <property name="hibernate.default_schema">protein_tracker</property>

  <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

  <property name="hibernate.show_sql">true</property>

 </session-factory>
</hibernate-configuration>

我有这个类有开始休眠的基础知识：

package com.simpleprogramer;

import org.hibernate.HibernateException;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistryBuilder;
import org.hibernate.service.ServiceRegistry;

public class HibernateUtilities {

    private static SessionFactory sessionFactory;
    private static ServiceRegistry serviceRegistry;

    static{
        try{
            Configuration configuration = new Configuration().configure();

            serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry();

            sessionFactory = configuration.buildSessionFactory(serviceRegistry);
        }
        catch(HibernateException exeption)
        {
            System.out.println("Problem creating session factory!");
        }
    }

    public static SessionFactory getSessionFactory(){
        return sessionFactory;
    }

}

和主要测试hibernate会话，我不知道是null：

package com.simpleprogramer;

import org.hibernate.Session;

public class program {

    public static void main(String[] args) {
        System.out.println("Hola mundo");
        Session session = HibernateUtilities.getSessionFactory().openSession();
        session.close();
    }

}

从控制台收到此错误：

Hola mundo
oct 01, 2013 2:12:31 AM org.hibernate.annotations.common.Version <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {4.0.2.Final}
oct 01, 2013 2:12:31 AM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {4.2.6.Final}
oct 01, 2013 2:12:31 AM org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
oct 01, 2013 2:12:31 AM org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
oct 01, 2013 2:12:31 AM org.hibernate.cfg.Configuration configure
INFO: HHH000043: Configuring from resource: /hibernate.cfg.xml
oct 01, 2013 2:12:31 AM org.hibernate.cfg.Configuration getConfigurationInputStream
INFO: HHH000040: Configuration resource: /hibernate.cfg.xml
oct 01, 2013 2:12:31 AM org.hibernate.internal.util.xml.DTDEntityResolver resolveEntity
WARN: HHH000223: Recognized obsolete hibernate namespace http://hibernate.sourceforge.net/. Use namespace http://www.hibernate.org/dtd/ instead. Refer to Hibernate 3.6 Migration Guide!
oct 01, 2013 2:12:31 AM org.hibernate.cfg.Configuration doConfigure
INFO: HHH000041: Configured SessionFactory: null
oct 01, 2013 2:12:31 AM org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000402: Using Hibernate built-in connection pool (not for production use!)
Problem creating session factory!
Exception in thread "main" java.lang.NullPointerException
    at com.simpleprogramer.program.main(program.java:9)

您好，感谢您的建议exeption.printStacktrace（System.out）;.我发现我的jdbc驱动程序没有加载，然后意识到它根本没有加载到proyect上（我认为配置自动加载无论驱动程序是什么或者是什么）。所以我下载了相应的jar，它的工作原理。谢谢你的建议！

Hibernate无法测试我的会话，是null

0 个答案: