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您好我正在使用带有 Fedora 17 版的 Linux 操作系统，我的 Hibernate 配置文件如下

<hibernate-configuration>


   <session-factory>
   <property name="hibernate.dialect">
      org.hibernate.dialect.MySQLDialect
   </property>
   <property name="hibernate.connection.driver_class">
      com.mysql.jdbc.Driver
   </property>

   <!-- Assume test is the database name -->
   <property name="hibernate.connection.url">
      jdbc:mysql://localhost:3306/Test
   </property>
   <property name="hibernate.connection.username">
      root
   </property>
   <property name="hibernate.connection.password">
      root
   </property>

<property name="show_sql">false</property>
<property name="format_sql">false</property>
<property name="use_sql_comments">false</property>
   <property name="hibernate.connection.pool_size">40</property>  

    <property name="hibernate.c3p0.min_size">1</property>
    <property name="hibernate.c3p0.max_size">20</property>
    <property name="hibernate.c3p0.timeout">300</property>
    <property name="hibernate.c3p0.max_statements">50</property>
    <property name="hibernate.c3p0.idle_test_periods">3000</property>     
    <property name="current_session_context_class">thread</property>
    <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
    <property name="hibernate.c3p0.acquire_increment">1</property>

</hibernate-configuration>


   </session-factory>

在服务器中使用此配置，我经常收到以下错误

SEVERE: Servlet.service() for servlet [jsp] in context with path [] threw exception [org.hibernate.service.UnknownServiceException: Unknown service requested [org.hibernate.stat.spi.StatisticsImplementor]] with root cause
org.hibernate.service.UnknownServiceException: Unknown service requested [org.hibernate.stat.spi.StatisticsImplementor]
        at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:126)
        at org.hibernate.internal.SessionFactoryImpl.getStatisticsImplementor(SessionFactoryImpl.java:1468)
        at org.hibernate.internal.SessionFactoryImpl.getStatistics(SessionFactoryImpl.java:1464)
        at org.hibernate.internal.SessionImpl.close(SessionImpl.java:346)

我的连接代码如下，

public class DBConnection{

    private static  SessionFactory factory; 

    private static DBConnection singleton = new DBConnection();

    // private static final SessionFactory sessionFactory;
    private DBConnection(){ }

    /* Static 'instance' method */
    public static DBConnection getInstance( ) {
       return singleton;
    }

    public static SessionFactory getSessionFactory(){

         if (factory == null ) {

             try {
                 factory = new Configuration().configure().buildSessionFactory();

               } catch (Throwable ex) {
                 System.err.println("Failed to create   sessionFactory object." + ex);
                 throw new ExceptionInInitializerError(ex);
             }
         }
         return factory;

     }


    public static Session getSession() 
    {
           return getSessionFactory().openSession();
    }



   // Call this during shutdown
  public static void close() {
        factory.close();
        factory=null;


   }

由于这个原因，我的应用程序变慢了，我可以在 MySQL 中看到睡眠查询。

如何解决这个问题？在这种环境下如何配置？非常感谢任何帮助。

谢谢！！

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