问答详情
源自：6-4 案例：Cookie在登录中的应用

错误代码500

org.apache.jasper.JasperException: An exception occurred processing JSP page /doLogin.jsp at line 34

31:       if(isUseCookies!=null&&isUseCookies.length>0){
32:        //鎶婄敤鎴峰悕鍜屽瘑鐮佷繚瀛樺埌Cookies涓�
33:        //1鑾峰緱鐢ㄦ埛鍚嶅拰瀵嗙爜
34:         String username = URLEncoder.encode(request.getParameter("username"),"utf-8");
35:         String password = URLEncoder.encode(request.getParameter("password"),"utf-8");
36:        //2鍒涘缓cookies瀵硅薄
37:        Cookie usernamecookies=new Cookie("username",username);


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:575)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)


root cause

java.lang.NullPointerException
java.net.URLEncoder.encode(URLEncoder.java:188)
org.apache.jsp.doLogin_jsp._jspService(doLogin_jsp.java:122)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:439)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)


note The full stack trace of the root cause is available in the Apache Tomcat/7.0.68 logs.

看了我的代码，和老师说的一样的，哪位大神帮我看看我是哪里错了

提问者：慕盖茨7610259 2016-04-19 21:19

个回答

  • 听风含泪
    2016-04-20 12:14:23
    已采纳

    把dologin的代码都贴上来看看呢。只看这个问题不太好看出来。

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  • 慕盖茨7610259
    2016-04-20 13:42:02

    <%@ page language="java" import="java.util.*,java.net.*" pageEncoding="utf-8"%>

    <%

    String path = request.getContextPath();

    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

    %>


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

    <html>

      <head>

        <base href="<%=basePath%>">

        

        <title>My JSP 'doLogin.jsp' starting page</title>

        

    <meta http-equiv="pragma" content="no-cache">

    <meta http-equiv="cache-control" content="no-cache">

    <meta http-equiv="expires" content="0">    

    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

    <meta http-equiv="description" content="This is my page">

    <!--

    <link rel="stylesheet" type="text/css" href="styles.css">

    -->


      </head>

      

      <body>

       <h1>登陆成功</h1> <br>

       <hr><br><br><br>

       <%

        request.setCharacterEncoding("utf-8");

          String isUseCookies[] =request.getParameterValues("isUseCookie");

          if(isUseCookies!=null&&isUseCookies.length>0){

           //把用户名和密码保存到Cookies中

           //1获得用户名和密码

            String username = URLEncoder.encode(request.getParameter("username"),"utf-8");

            String password = URLEncoder.encode(request.getParameter("password"),"utf-8");

           //2创建cookies对象

           Cookie usernamecookies=new Cookie("username",username);

           Cookie passwordcookies=new Cookie("passwore",password);

           //3设置保存时间

           usernamecookies.setMaxAge(846000);

           passwordcookies.setMaxAge(864000);  //最大保存时间是10天.

           //4保存cookie对象

           response.addCookie(usernamecookies);

           response.addCookie(passwordcookies);

          }

          else{

             //如没有选择保存，则删除保存

             //1先判断有无保存

            Cookie cookies[]=request.getCookies();

          if(cookies!=null&&cookies.length>0){

            for(Cookie c:cookies){

              if(c.getName().equals("username")||c.getName().equals("pw")){

                   c.setMaxAge(0);//设置保存时间为O

                   response.addCookie(c);

              }

          }

            }

          }

       

        %>

       <a href="Users.jsp" target="_blank">查看用户信息</a>

      </body>

    </html>



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