下面是我使用hibernate连接到db的数据库配置：

public class HibernateUtil {
public static HibernateUtil mInstance = null;

public static HibernateUtil getInstance(DBMode dbMode) {
    if (mInstance == null) {
        mInstance = new HibernateUtil(dbMode);
    }
    return mInstance;
}

private SessionFactory sessionFactory;

private HibernateUtil(DBMode dbMode) {
        buildSessionFactoryTest();
        }

private void buildSessionFactoryTest() {
    Configuration configuration = new Configuration()
            .setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLDialect")
            .setProperty("hibernate.connection.driver_class", "com.mysql.jdbc.Driver")
            .setProperty("hibernate.connection.url",
                    "jdbc:mysql://ip:port/DB?createDatabaseIfNotExist=true&autoReconnect=true&useUnicode=true&connectionCollation=utf8_general_ci&characterSetResults=utf8&characterEncoding=utf-8")
            .setProperty("hibernate.connection.username", "root")
            .setProperty("hibernate.connection.password", "password")
            .setProperty("hibernate.hbm2ddl.auto", "update").setProperty("c3p0.max_size", "20")
            .setProperty("c3p0.timeout", "1800").setProperty("3p0.min_size", "5")
            .setProperty("hibernate.c3p0.max_statements", "0")
            .setProperty("connection.provider_class", "org.hibernate.connection.C3P0ConnectionProvider")
            .configure();
    ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties())
            .buildServiceRegistry();
    sessionFactory = configuration.buildSessionFactory(serviceRegistry);
}

public Session getSession() {
    Session session;
    try {
        session = sessionFactory.getCurrentSession();
    } catch (HibernateException e) {
        session = sessionFactory.openSession();
    }
    if (session == null || sessionFactory.isClosed() || !session.isConnected() || !session.isOpen()) {
        sessionFactory.close();
            buildSessionFactoryTest();
        session = sessionFactory.openSession();
    }
    return session;
}

}
下面是如何从hibernateutil获取会话：

Session session = HibernateUtil.getInstance(dbMode).getSession();

我的应用程序大多数时候都正常工作，但有时当我向数据库添加一个对象并执行查询时，新添加的对象不会返回。我猜连接已被缓存并返回旧结果。我的配置有问题吗？