Hibernate 事务未正常启动？？？？

Exception in thread "main" org.hibernate.TransactionException: Transaction not successfully started
 at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:100)
 at app.Test.count(Test.java:77)
 at app.Test.main(Test.java:46)

 

 

源码如下：

 

// 统计每种类型产品的数量，包括子类型下面的类型。直到根类型是null
 @SuppressWarnings("unchecked")
 static void count()
 {
  Session session = sessionFactory.openSession();
  Transaction tran = session.beginTransaction();
  Query query = session.createQuery(" from Product");
  List<Product> list = query.list();
  for (Product p : list)
  {
   // 输出测试
   System.out.println("name:" + p.getName());
   ProductType type = p.getType();
   // 输出测试
   System.out.println("name:" + type.getName());
   type.setCount(type.getCount() + 1);
   // 更新类型的数量
   session.update(type);
   ProductType parent = type.getParents();
   while (parent != null)
   {
    // 输出测试
    System.out.println("name:" + parent.getName());
    parent.setCount(parent.getCount() + 1);
    // 更新类型的数量
    session.update(type);
    parent = parent.getParents();
   }
   tran.commit();
  }
  session.close();
 }