<%-- 
    Document   : vote
    Created on : 2011-9-15, 15:56:46
    Author     : Administrator
--%><%@page contentType="text/html" pageEncoding="GB2312"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd"><%@page language="java" import="java.sql.*"%>
<jsp:useBean id="connDbBean" scope="page" class="vote.VoteConn"/>
<%
  String rb = request.getParameter("type");
  if(rb != null && rb != "") {
    String sql = "update vote Set c_num=c_num+1 where id=" + rb;
    connDbBean.executeUpdate( sql );
  }
%>
<jsp:forward page="details.jsp"/>报错:
HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: An exception occurred processing JSP page /vote.jsp at line 2017:     connDbBean.executeUpdate( sql );
18:   }
19: %>
20: <jsp:forward page="details.jsp"/>
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:401)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
root cause org.apache.jasper.JasperException: An exception occurred processing JSP page /details.jsp at line 2825: <%
26:    // 获取总票数
27:    ResultSet tmpRs = connDbBean.executeQuery("select sum(c_num) As totalnum from vote");
28:    tmpRs.next();
29:    tot_num = tmpRs.getInt("totalnum");
30:    tmpRs.close();
31:    ResultSet rs = connDbBean.executeQuery("select * from vote");
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
org.apache.jasper.runtime.PageContextImpl.doForward(PageContextImpl.java:706)
org.apache.jasper.runtime.PageContextImpl.forward(PageContextImpl.java:677)
org.apache.jsp.vote_jsp._jspService(vote_jsp.java:79)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
root cause java.lang.NullPointerException
org.apache.jsp.details_jsp._jspService(details_jsp.java:86)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
org.apache.jasper.runtime.PageContextImpl.doForward(PageContextImpl.java:706)
org.apache.jasper.runtime.PageContextImpl.forward(PageContextImpl.java:677)
org.apache.jsp.vote_jsp._jspService(vote_jsp.java:79)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.26 logs.
--------------------------------------------------------------------------------Apache Tomcat/6.0.26

解决方案 »

  1.   

    <%--  
      Document : vote
      Created on : 2011-9-15, 15:56:46
      Author : Administrator
    --%><%@page contentType="text/html" pageEncoding="GB2312"%>
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
      "http://www.w3.org/TR/html4/loose.dtd">试下
    <%@page language="java" import="java.sql.*"%>
    <jsp:useBean id="connDbBean" scope="page" class="vote.VoteConn"/>
    <%
      String rb = request.getParameter("type");
      if(rb != null && rb.isEmpty()) {
      String sql = "update vote Set c_num=c_num+1 where id=" + rb;
      connDbBean.executeUpdate( sql );
      }
    %>
    <jsp:forward page="details.jsp"></jsp:forward>
      

  2.   

    root cause org.apache.jasper.JasperException: An exception occurred processing JSP page /details.jsp at line 2825: <%
    26: // 获取总票数
    27: ResultSet tmpRs = connDbBean.executeQuery("select sum(c_num) As totalnum from vote");
    28: tmpRs.next();
    29: tot_num = tmpRs.getInt("totalnum");
    30: tmpRs.close();
    31: ResultSet rs = connDbBean.executeQuery("select * from vote");
    root cause java.lang.NullPointerExceptiontmpRs为null了