HTTP Status 500啦！
本人菜啊，看不懂啊.....


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: Exception in JSP: /guest_do.jsp:18

15: String pwd=request.getParameter("guest_pwd");
16: %>
17: <%
18: if (rand.equals(input)) {
19: int isSave=gg.addMessage(gu,pwd);
20: if(isSave==1)
21: {


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)


root cause

java.lang.NullPointerException
org.apache.jsp.guest_005fdo_jsp._jspService(guest_005fdo_jsp.java:84)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)


note The full stack trace of the root cause is available in the Apache Tomcat/5.5.28 logs.



MyEclipse JAVA 代码 String
[解决办法]
String rand = (String)session.getAttribute("rand");
String input = request.getParameter("code");
String pwd=request.getParameter("guest_pwd");

你确定这三个参数都是有值的？，明显空指针异常啊