java - 建立SessionFactory时发生NullPointerException

我使用Hibernate创建了一个简单的类示例，但是出现以下错误：

Initial SessionFactory creation failed. java.lang.ExceptionInInitializerError
java.lang.ExceptionInInitializerError
    at org.hibernate.cfg.Configuration.reset(Configuration.java:249)
    at org.hibernate.cfg.Configuration.<init>(Configuration.java:216)
    at org.hibernate.cfg.Configuration.<init>(Configuration.java:220)
    at it.univaq.mwt.tplabs0.Test.main(Test.java:14)
Caused by: java.lang.NullPointerException
    at org.hibernate.util.ConfigHelper.getResourceAsStream(ConfigHelper.java:167)
    at org.hibernate.cfg.Environment.<clinit>(Environment.java:585)
    ... 4 more
Exception in thread "main" java.lang.NullPointerException
    at it.univaq.mwt.tplabs0.Test.main(Test.java:20)

我的测试班：

package it.univaq.mwt.tplabs0;

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

public class Test {

  public static void main(String[] args) {

    SessionFactory sessionFactory = null;

    try {
      sessionFactory = new Configuration().configure().buildSessionFactory();
    } catch (Throwable ex) {
      System.err.println("Initial SessionFactory creation failed. " + ex);
      ex.printStackTrace();
    }

    Session session = sessionFactory.getCurrentSession();
    session.beginTransaction();

    System.out.println("Creating element");
    Element el = new Element("prova", 1);

    session.save(el);
    System.out.println("Committing Tx");
    session.getTransaction().commit();

    System.out.println("Closing Session");
    if (session.isOpen())
        session.close();
  }
}

我的Hibernate配置文件：

<?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 name="">
        <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="hibernate.connection.password">master</property>
        <property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:XE</property>
        <property name="hibernate.connection.username">master</property>
        <property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
        <property name="hbm2ddl.auto">create</property>
        <property name="current_session_context_class">thread</property>
     <mapping class="it.univaq.mwt.tplabs0.Element" resource="it/univaq/mwt/tplabs0/Element.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

我的图书馆：


antlr-2.7.6.jar
asm.jar
asm-attrs.jar
c3p0-0.9.1.jar
cglib-2.2.jar
commons-collections-3.1.jar
commons-logging-1.0.4.jar
并发1.3.2.jar
连接器.jar
dom4j-1.6.1.jar
ehcache-1.2.3.jar
hibernate3.jar
jaas.jar
javassist.jar
jboss-cache.jar
jboss-common.jar
jboss-jmx.jar
jboss-system.jar
jdbc2_0-stdext.jar
jgroups-2.2.8.jar
jta.jar
log4j-1.2.15.jar
oscache-2.1.jar
proxool-0.8.3.jar
swarmcache-1.0rc2.jar
slf4j-api-1.7.7.jar
slf4j-log4j12-1.7.7.jar


启动此简单执行，我从上面得到了错误。我正在使用的数据库是Oracle 11g。

发生了什么？

最佳答案

您的代码说了什么：

   1. SessionFactory sessionFactory = null;
   2.   try {
   3.     sessionFactory = new Configuration().configure().buildSessionFactory();
   4.   } catch (Throwable ex) {
   5.     System.err.println("Initial SessionFactory creation failed. " + ex);
   6.     ex.printStackTrace();
   7.   }
   8.
   9.   Session session = sessionFactory.getCurrentSession();
        // Here you are trying to access the Session which is not even created

您正在尝试访问未在CurrentSessionContext中配置或完全未创建的Session。

将第9行的代码替换为：

Session session = sessionFactory.openSession();

您将看到自己的状态。