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『新手』JSP的一个编译错误，在线等 马上结帖。

摘要: 『新手』JSP的一个编译错误，在线等 马上结帖。

<%@ page import="javax.servlet.http.Cookie,java.util.*" %>
<%
String userName="haha";
Cookie[] cookie=request.getCookies();
Cookie cookie_response=null;
List list=Arrays.asList(cookie);
Iterator it=list.iterator();
while(it.hasNext())
{
Cookie temp=(Cookie)it.next();
if(temp.getName().equals(userName+"_access_time"))
{
cookie_response=temp;
break;
}
}

out.println("当前时间："+new java.util.Date()+"
");
if(cookie_response!=null)
{
out.println("上次访问时间："+cookie_response.getValue());
cookie_response.setValue(new Date().toString());
}
else
{
cookie_response=new Cookie(userName+"_access_time",new java.util.Date().toString());
}

response.addCookie(cookie_response);
response.setContentType("text/html");
response.flushBuffer();
%>

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运行时的错误信息如下：

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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: /LX/response.jsp:6

3: String userName="hellking";
4: Cookie[] cookie=request.getCookies();
5: Cookie cookie_response=null;
6: List list=Arrays.asList(cookie);
7: Iterator it=list.iterator();
8: while(it.hasNext())
9: {


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
java.util.Arrays$ArrayList.(Unknown Source)
java.util.Arrays.asList(Unknown Source)
org.apache.jsp.LX.response_jsp._jspService(response_jsp.java:50)
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)


note The full stack trace of the root cause is available in the Apache Tomcat/5.5.17 logs.


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Apache Tomcat/5.5.17

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cookie第一次的值肯定是空值....出错....

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判断一下,cookie为空则只添加...

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新手不会啊 书上这么写的。。。。。。。

应该怎么写呢 最好有代码 马上结帖

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谢谢qiyadeng 弄好了

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