出现大500啦。。求救

问题：建一个监听类来实现一个访问次数

在myeclipse里建一个WebTest We工程
建好了.建一个类名叫Count.java
Count内容是

public class Count {

public Count(){}

public static int count=0;
public static void up(){
   count++;
}
public static void down(){
  count--;
}
public static int resultSet(){
return count;
}
}

在建一个Servlet类继承自HttpSessionLister

内容是：

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

public class CountServlet extends HttpServlet implements HttpSessionListener {

public void sessionCreated(HttpSessionEvent arg0) {

Count.up();
// TODO Auto-generated method stub

}

public void sessionDestroyed(HttpSessionEvent arg0) {

Count.down();
// TODO Auto-generated method stub

}

/**
* Constructor of the object.
*/
public CountServlet() {
super();
}

/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}

/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occure
*/
public void init() throws ServletException {
// Put your code here
}

}

在建一个显示的JSP名叫show.jsp

内容是：
<%@ page language="java" import="java.util.*" pageEncoding="Gb2312"%>
<%
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 'show.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">


  </head>

  <body>
   访问次数是<%=Count.resultSet() %>
  </body>
</html>

在http://127.0.0.1:8080/WebTest/show.jsp

在运行时。出现500大字。

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: Unable to compile class for JSP

An error occurred at line: 26 in the jsp file: /show.jsp
Generated servlet error:
Count cannot be resolved

org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:375)
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

org.apache.jasper.JasperException: Unable to compile class for JSP

An error occurred at line: 26 in the jsp file: /show.jsp
Generated servlet error:
Count cannot be resolved

org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:328)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:414)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:297)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:276)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:264)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:563)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:303)
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.

弄不清楚吖。。求救。。。

6 个解决方案

#1

访问次数是 <%=Count.resultSet() %>
这里的Count哪里来的?如果是你自己写的java class的话,要先引入到JSP来才行.

#2

我可以点出来吖。。不用导吖？？？

开发JSP.什么时候要配WEB.XML？？这个用上工具不是很知道。初学者。

在线等。。。

我在WEB。XML没有配置。能出来吗？？

#3

将Count 与CountServlet 放在一个包下面，在jsp中写<%=包名.Count.resultSet() %>就行了

#4

不用配web.xml吗？？
我在JB里也是这样做的。？？没有错吖。。。。来到MYECLIPSE出大500吖？？？

#5

xml 中写的东西为：
<servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>CountServlet</servlet-name>
    <servlet-class>包名.CountServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>CountServlet</servlet-name>
    <url-pattern>/servlet/CountServlet</url-pattern>
  </servlet-mapping>
但用MYECLIPSE，此web.xml制动生成

#6

在jb中为什么好用，我不知道

#1