我使用JSTL标签，如下所示：
?
<c:when test="${!empty flist && fn:length(flist)>3 } ">
<c:forEach items="${flist }" var="f" begin="${fn:length(flist)-3}" end="${fn:length(flist)}">
<c:if test="${f.fileState!=1}">
<tr><td width="90px;"><a href="<c:url value="/showFileIndex.do" />"><font color="blue"> [知识培训]:</a></font></td><td align="left"><a href="<c:url value="/file/filePriview.do?filePK=${f.fileId}" />">${fnx:subStringHtml(f.fileAliaName,18,'...',false) }</td>
<td width="60px;"><font color="blue">发布人 ：</font></td><td align="left">${fnx:subStringHtml(f.user.userName,18,'...',false) }</td>
<td width="80px;"><font color="blue">发布时间 ：</font></td><td align="left"><fmt:formatDate value="${f.uploadDate }" pattern="yyyy-MM-dd" /></td>
</tr>
</c:if>
</c:forEach>
</c:when>
?运行时报如下异常：
?
严重: Servlet.service() for servlet jsp threw exception
org.apache.jasper.JasperException: Unable to compile class for JSP:
An error occurred at line: 93 in the jsp file: /WEB-INF/views/informations.jsp
The method setTest(boolean) in the type WhenTag is not applicable for the arguments (String)
90: </c:choose>
91:
92: <c:choose>
93: <c:when test="${!empty flist && fn:length(flist)>3 } ">
94: <c:forEach items="${flist }" var="f" begin="${fn:length(flist)-3}" end="${fn:length(flist)}">
95: <c:if test="${f.fileState!=1}">
96: <tr><td width="90px;"><a href="<c:url value="/showFileIndex.do" />"><font color="blue"> [abcdefghijk]:</a></font></td><td align="left"><a href="<c:url value="/file/filePriview.do?filePK=${f.fileId}" />">${fnx:subStringHtml(f.fileAliaName,18,'...',false) }</td>
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:439)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:334)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:312)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:299)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:586)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:551)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:488)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:230)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1060)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:798)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:716)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:647)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:552)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:551)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:488)
at org.apache.taglibs.standard.tag.common.core.ImportSupport.acquireString(ImportSupport.java:314)
at org.apache.taglibs.standard.tag.common.core.ImportSupport.doEndTag(ImportSupport.java:171)
at org.apache.jsp.decorators.main_jsp._jspx_meth_c_005fimport_005f1(main_jsp.java:1030)
at org.apache.jsp.decorators.main_jsp._jspx_meth_c_005fif_005f2(main_jsp.java:1000)
at org.apache.jsp.decorators.main_jsp._jspService(main_jsp.java:377)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:551)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:488)
at com.opensymphony.module.sitemesh.filter.PageFilter.writeDecorator(PageFilter.java:173)
at com.opensymphony.module.sitemesh.filter.PageFilter.applyDecorator(PageFilter.java:158)
at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:62)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:176)
at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:145)
at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:92)
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:381)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Unknown Source)
?它说是when那里出现异常，开始以为是业务逻辑的错，后来才知道原来是自己在写when标签里的test的最后一个引号和大括号之间多了一个空格，就这么一个小点导致了异常，所以写程序还是要心细一点。解决方案如下:
<c:when test="${!empty flist && fn:length(flist)>3 }">
?
我的异常网推荐解决方案：org.apache.jasper.JasperException: Unable to compile class,http://www.myexception.cn/j2ee/2308.html