tion org.hibernate.TransactionException: Transaction not successfully

程序代码：
public List<WenshuInfo> findBySql(String sql) {
    log.debug("findBuSql WenshuInfo instances");
    Transaction tran = null;
    Session session = HibernateSessionFactory.getSession();
    
    try {
      tran = session.beginTransaction();
      Query queryObject = session.createQuery(sql);
      
      session.flush();
      tran.commit();      
      return queryObject.list();
    } catch (RuntimeException re) {
      if (null != tran) {
        tran.rollback();
        tran = null;
      }
      log.error("findBuSql failed", re);
      re.printStackTrace();
      return null;
    }
  }
 
关键代码：return queryObject.list();
 
修改后的代码：
public List<WenshuInfo> findBySql(String sql) {
    log.debug("findBuSql WenshuInfo instances");
    Transaction tran = null;
    Session session = HibernateSessionFactory.getSession();
    
    try {
      tran = session.beginTransaction();
      Query queryObject = session.createQuery(sql);
      List<WenshuInfo> list = queryObject.list();
      session.flush();
      tran.commit();
      return list;
    } catch (RuntimeException re) {
      if (null != tran) {
        tran.rollback();
        tran = null;
      }
      log.error("findBuSql failed", re);
      re.printStackTrace();
      return null;
    }
  }
 
异常信息：
  at org.hibernate.transaction.JDBCTransaction.rollback(JDBCTransaction.java:149)
  at com.mylegist.lawgeneral.dao.WenshuInfoDaoIMP.findBySql(WenshuInfoDaoIMP.java:86)
  at com.mylegist.lawgeneral.service.WenshuInfoServiceIMP.findBySql(WenshuInfoServiceIMP.java:28)
  at com.mylegist.lawgeneral.action.WenshuAction.execute(WenshuAction.java:35)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  at java.lang.reflect.Method.invoke(Method.java:597)
  at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:404)
  at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:267)
  at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:229)
  at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:221)
  at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
  at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
  at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223)
  at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
  at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
  at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:150)