我这样写为什么在第一次启动的时候会抛出异常

我这样写为什么在第一次启动的时候会抛出  java.lang.NullPointerException 异常，点了页面上的其他连接后，再刷新一次就不会了
<%@ page language="java" contentType="text/html;charset=gbk"%>
<%@ include file="/taglibs.jsp" %><html>
 
<head>
</head>
<frameset rows="25%,*">
    <frame src=<%=request.getContextPath() %>/front/head/headindex.jsp />
    <frameset cols="25%,*">
       <frame src=<%=request.getContextPath() %>/front/link/linkindex.jsp  />
     <frame src="zhengzhi.do?zhengzhi=<%="all" %>" name="mainFrame"/>
    </frameset>
        
</frameset> <body>
</body>
</html>
是在这个地方抛出异常的
<frame src="zhengzhi.do?zhengzhi=<%="all" %>" name="mainFrame"/>
我想应该是第一次进入的时候zhengshi 这个参数没有值传入，那要想第一次进入的时候不抛出异常，这句话要怎么改呢，谢谢

解决方案 »

  1.   

    -------------------------
     <frame src="zhengzhi.do?zhengzhi=<%="all" %>" name="mainFrame"/>-------------------------不知道楼主这样写是什么意思,这样就可以啊
    <frame src="zhengzhi.do?zhengzhi=all" name="mainFrame"/>
      

  2.   

    Netself(我是一只来自北方的鸟) 
    我按你的写法还是会抛出异常啊
    异常信息截取了一部分%%%% Error Creating SessionFactory %%%%
    org.hibernate.MappingException: Error reading resource: testhibernate/TbContent.hbm.xml
    at org.hibernate.cfg.Configuration.addResource(Configuration.java:452)
    at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1263) at hibernate.HibernateSessionFactory.rebuildSessionFactory(HibernateSessionFactory.java:59)
    at hibernate.HibernateSessionFactory.getSession(HibernateSessionFactory.java:43)
    at com.yourcompany.struts.action.ZhengzhiAction.execute(ZhengzhiAction.java:51)
    at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
    at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
    at org.apache.catalina.core.StandardValveContext.invokeNext(
    at org.apache.catalina.valves.ErrorReportValve.invoke
    at org.
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
    at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)Caused by: org.dom4j.DocumentException: FWK005 parse may not be called while parsing. Nested exception: FWK005 parse may not be called while parsing.
    at org.dom4j.io.SAXReader.read(SAXReader.java:484)
    at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:398)
    ... 39 more
    java.lang.NullPointerException
    at com.yourcompany.struts.action.ZhengzhiAction.execute(ZhengzhiAction.java:56)
    at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
    at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
    %%%% Error Creating SessionFactory %%%%
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
    at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
    at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
    at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160) at java.lang.Thread.run(Thread.java:595)
    org.hibernate.MappingException: Error reading resource: testhibernate/TbContent.hbm.xml
    at org.hibernate.cfg.Configuration.addResource(Configuration.java:452)
    at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1263)
    at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1235)
    at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1217)
    at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1184)
    at org.hibernate.cfg.Configuration.configure(Configuration.java:1112)
    at hibernate.HibernateSessionFactory.rebuildSessionFactory(HibernateSessionFactory.java:59)
    at hibernate.HibernateSessionFactory.getSession(HibernateSessionFactory.java:43)
    at com.yourcompany.struts.action.LinkAction.execute(LinkAction.java:54)
    at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
    at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
    at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
    at org.apache.catalina.core.StandardPipeline.invoke(
    Caused by: org.hibernate.MappingException: java.lang.NullPointerException
    at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:408)
    at org.hibernate.cfg.Configuration.addResource(Configuration.java:449)
    ... 38 more
    Caused by: java.lang.NullPointerException
    at org.hibernate.cfg.HbmBinder.getExtendsNeeded(HbmBinder.java:2774)
    at org.hibernate.cfg.HbmBinder.bindRoot(HbmBinder.java:113)
    at org.hibernate.cfg.Configuration.add(Configuration.java:362)
    at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:400)
    ... 39 more
    java.lang.NullPointerException
    at com.yourcompany.struts.action.LinkAction.execute(LinkAction.java:60)
      

  3.   

    request.getContextPath() 第一次获得是null值，
    再次刷新已经就有值了
      

  4.   

    all是变量名还是值？
    如果是变量名：
    <frame src="zhengzhi.do?zhengzhi=<%=all %>" name="mainFrame"/>
    如果是值：
    <frame src="zhengzhi.do?zhengzhi=all" name="mainFrame"/>