java.lang.NullPointerException问题

eimhee 2006-09-15 07:12:47

大家帮我看看运行时出现了这个错误，　这是为什么呢
org.apache.jasper.JasperException: Exception in JSP: /cook/login.jsp:6

3: String UserName = "", UserEMail = "", LoginDate = "";
4: Cookie temp = null;
5: Cookie[] cookies = request.getCookies();
6: int cookielen = cookies.length;
7:
8: for (int i = 0; i < cookielen; i++) {
9: temp = cookies[i];

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:504)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.lang.NullPointerException
org.apache.jsp.cook.login_jsp._jspService(login_jsp.java:48)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

<%@ page language="java" contentType="text/html;charset=gb2312"%>
<%
String UserName = "", UserEMail = "", LoginDate = "";
Cookie temp = null;
Cookie[] cookies = request.getCookies();
int cookielen = cookies.length;

for (int i = 0; i < cookielen; i++) {
temp = cookies[i];
if (temp.getName().equals("Name")) {
UserName = temp.getValue();
} else if (temp.getName().equals("E_Mail")) {
UserEMail = temp.getValue();
} else if (temp.getName().equals("LoginDate")) {
LoginDate = temp.getValue();
}
}
int tmplen = LoginDate.length();
boolean FirstLogin;
if (tmplen != 0) {
FirstLogin = false;
} else {
FirstLogin = true;
}
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>

<title>Cookie 有效时间的设置</title>

<style type="text/css">

</style>
</head>

<body>
<div align="center" class="STYLE1" >Cookie有效时间的设置 </div>
<p>
<%
if(FirstLogin==true)
{
%>

首度登陆的朋友请输入EMAIL
<%
}
else
{
%>
欢迎再次光临,您曾于<span class="STYLE2"><%= LoginDate %></span>
<%
}
%>
</p>
<form name="form1" method="post" action="settime.jsp">
<p>姓名:
<input name="tmpName" type="text" id="tmpName" value="<%= UserName%>">
</p>
<p>E-Mail
<input name="tmpE_Mail" type="text" id="tmpE_Mail" value="<%= UserEMail %>">
</p>
<p>
<input name="Submit1" type="submit" id="Submit1" value="登陆">
</p>
</form>
<p> </p>
</body>
</html>

...全文