Question

jsp获取cookie的问题

我的jsp有一段程序是：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String UserName = "";
String UserEmail = "";
String LoginDate = "";
Cookie temp = null;
Cookie cookies[] = request.getCookies();
for(int i = 0;i<cookies.length;i++){
temp = cookies[i];
if(temp.getName().equals("Name"))
{
UserName = temp.getValue();
}
else if(temp.getName().equals("Email"))
{
UserEmail = temp.getValue();

}
else if(temp.getName().equals("Date"))
{
LoginDate = temp.getValue();
}
int temLen = LoginDate.length();
boolean FirstLogin;
if(temLen != 0)
{
FirstLogin = true;
}
else
{
FirstLogin = false;
}
}
%>
但是运行时出现了如下错误：
type Exception report

message

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 /testLogin.jsp at line 8

5: String LoginDate = "";
6: Cookie temp = null;
7: Cookie cookies[] = request.getCookies();
8: for(int i = 0;i<cookies.length;i++){
9: temp = cookies[i];
10: if(temp.getName().equals("Name"))
11: {

我该如何办呢？

Answer 1

在第一行中加上加一行if(cookies!=null)就行
具体如下：

Cookie cookies[]=request.getCookies(); //读出用户硬盘上的Cookie，并将所有的Cookie放到一个cookie对象数组里面
Cookie sCookie=null;
for(int i=0;i<cookies.length-1;i++){ //用一个循环语句遍历刚才建立的Cookie对象数组
sCookie=cookies[i]; //取出数组中的一个Cookie对象
if(sCookie!=null){
if(("cookieName").equals(sCookie.getName())){
pageContext.setAttribute("SavedUserName",sCookie.getValue());
}
}

//保存用户名到cookies

String user_name=request.getParameter("user_name");
if(!"".equals(user_name) && request.getParameter("RmbUser")!=null){
Cookie cookie=new Cookie("usernamecookie",user_name);
cookie.setMaxAge(365*24*60*60); //保存365天
response.addCookie(cookie); //写COOKIE
}

Answer 2

7: Cookie cookies[] = request.getCookies();
加一行:
if(cookies!=null)
8: for(int i = 0;i<cookies.length;i++){
9: temp = cookies[i];
10: if(temp.getName().equals("Name"))
11: {

Answer 3

异常了 cookies可能为空
在8行前加
if(cookies==null){cookies="";}
最好用try catch模式~