求好心人帮忙（jsp）

java类
import java.text.SimpleDateFormat;
import java.util.Date;public class UseBean {
Date date= new Date();
public String today(String s)
{
SimpleDateFormat formatter= new SimpleDateFormat(s);
return formatter.format(date);
}
}jsp页面
<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<%
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 'useBean.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>
   <jsp:useBean id="usebeans" class="UseBean" scope="page"></jsp:useBean>
   现在是北京时间：<br/>
   <%=usebeans.today("yyyy-MM-dd HH:mm:ss") %>
  </body>
</html>
下面的是错误信息2012-8-8 16:16:54 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
org.apache.jasper.JasperException: Unable to compile class for JSP: An error occurred at line: 24 in the jsp file: /useBean.jsp
UseBean cannot be resolved to a type
21:  -->
22:   </head>
23:   <body>
24:    <jsp:useBean id="usebeans" class="UseBean" scope="page"></jsp:useBean>
25:    现在是北京时间：<br/>
26:    <%=usebeans.today("yyyy-MM-dd HH:mm:ss") %>
27:   </body>
An error occurred at line: 24 in the jsp file: /useBean.jsp
UseBean cannot be resolved to a type
21:  -->
22:   </head>
23:   <body>
24:    <jsp:useBean id="usebeans" class="UseBean" scope="page"></jsp:useBean>
25:    现在是北京时间：<br/>
26:    <%=usebeans.today("yyyy-MM-dd HH:mm:ss") %>
27:   </body>
An error occurred at line: 24 in the jsp file: /useBean.jsp
UseBean cannot be resolved to a type
21:  -->
22:   </head>
23:   <body>
24:    <jsp:useBean id="usebeans" class="UseBean" scope="page"></jsp:useBean>
25:    现在是北京时间：<br/>
26:    <%=usebeans.today("yyyy-MM-dd HH:mm:ss") %>
27:   </body>
Stacktrace:
at org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:92)
at org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330)
at org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:423)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:308)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:286)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:273)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:566)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)

解决方案 »

  1.   

    UseBean cannot be resolved to a type -- 无法识别UseBean这个类
    22: </head>
    23: <body>
    24: <jsp:useBean id="usebeans" class="UseBean" scope="page"></jsp:useBean>你这个类 UseBean，没有包路径（package）的么？此外，确认UseBean这个类，已经正确发布了么？比如  WEB-INF\classes\ 中？或者借助Eclipse发布的？
      

  2.   

    最好不要没有路径的包。还是增加路径比较好，便于引用和检查错误。比如：
    package xxoo;
    import java.text.SimpleDateFormat;
    import java.util.Date;public class UseBean {JSP前面增加：
    <%@ import="ooxx.UseBean"%>这句话修改下，增加包路径：
    <jsp:useBean id="usebeans" class="ooxx.UseBean" scope="page"></jsp:useBean>
      

  3.   

    <jsp:useBean id="usebeans" class="UseBean" scope="page"></jsp:useBean>
    class应该是包名.类名
      

  4.   

    UseBean ,这个最好eclipse打代码,自动导入,那个路径肯定没问题,如果是自己写的,往往就找不到