问题遇到的现象和发生背景
系统功能报错，弹出错误及界面
问题相关代码，请勿粘贴截图
运行结果及报错内容
HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: org.hibernate.AssertionFailure: null id in com.ticket.bean.Order entry (don't flush the Session after an exception occurs)
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:541)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:435)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause
org.hibernate.AssertionFailure: null id in com.ticket.bean.Order entry (don't flush the Session after an exception occurs)
org.hibernate.event.def.DefaultFlushEntityEventListener.checkId(DefaultFlushEntityEventListener.java:78)
org.hibernate.event.def.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:187)
org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:143)
org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:219)
org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:99)
org.hibernate.event.def.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:58)
org.hibernate.impl.SessionImpl.autoFlushIfRequired(SessionImpl.java:997)
org.hibernate.impl.SessionImpl.list(SessionImpl.java:1142)
org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:835)
com.ticket.dao.OrderDao.get(OrderDao.java:73)
org.apache.jsp.wddd_jsp._jspService(wddd_jsp.java:97)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.13 logs.
