实现上传时，出现以下报错，请问是什么原因啊？比较急！！
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:   Unable   to   compile   class   for   JSP

An   error   occurred   at   line:   27   in   the   jsp   file:   /bysj/do_downloadfile.jsp

Generated   servlet   error:
        [javac]   Compiling   1   source   file

C:\Program   Files\Apache   Software   Foundation\Tomcat   5.0\work\Catalina\localhost\_\org\apache\jsp\bysj\do_005fdownloadfile_jsp.java:84:   cannot   access   com.jspsmart.upload.SmartUpload


An   error   occurred   at   line:   27   in   the   jsp   file:   /bysj/do_downloadfile.jsp

Generated   servlet   error:
bad   class   file:   C:\Program   Files\Apache   Software   Foundation\Tomcat   5.0\shared\classes\com\jspsmart\upload\SmartUpload.class
illegal   start   of   class   file
Please   remove   or   make   sure   it   appears   in   the   correct   subdirectory   of   the   classpath.
            SmartUpload   su   =   new   SmartUpload();  
            ^
1   error


org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:127)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:351)
org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:415)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:458)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:439)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:552)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:291)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)


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


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Apache   Tomcat/5.0.16

------解决方案--------------------
找不到SmartUpload 这个类的路徑

------解决方案--------------------


貌似你的包引用的有问题啊

检查一下你里面的这一行
<jsp:useBean id= "su " scope= "page " class= "com.jspsmart.upload.SmartUpload "/>


我的异常网推荐解决方案：The server encountered an internal error () that prevented it from fulfilling this request.,http://www.aiyiweb.com/java-web/317.html
我的异常网推荐解决方案：org.apache.jasper.JasperException: Unable to compile class,http://www