SSH里update问题

javax.servlet.ServletException: The given object has a null identifier: com.accp.entity.UserInfo; nested exception is org.hibernate.TransientObjectException: The given object has a null identifier: com.accp.entity.UserInfo
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:523)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.accp.filter.Fileter.doFilter(Fileter.java:24)