hibernate有关问题很

hibernate问题很急
javax.servlet.ServletException: could not execute query
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:545)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:486)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
ufe.gfz.action.Character.doFilter(Character.java:30)


root cause

org.hibernate.exception.GenericJDBCException: could not execute query
org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
org.hibernate.loader.Loader.doList(Loader.java:2148)
org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
org.hibernate.loader.Loader.list(Loader.java:2024)
org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:94)
org.hibernate.impl.SessionImpl.list(SessionImpl.java:1533)
org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283)
ufe.gfz.dao.UserDAO.findByNamePassword(UserDAO.java:42)
ufe.gfz.business.UserService.findByNamePassword(UserService.java:12)
ufe.gfz.action.LoginAction.execute(LoginAction.java:44)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
ufe.gfz.action.Character.doFilter(Character.java:30)


我用hibernate的时候有时回报这种错误，但有时就好了，不知道是什么问题。希望大家帮帮忙，很急，先谢谢了