这是我在Spring Web模型 - 视图 - 控制器（MVC）框架中的JSP文件中的代码。 Spring Web模型 - 视图 - 控制器（MVC）框架的版本是3.2.8，部署在WebLogic Server版本：12.1.2.0.0中。我正在使用jstl-1.2
<c:if test="${not empty form.attachment}">
${fn:length(form.attachment.bytes.length)}
</c:if>
其中
private MultipartFile attachment;
但我有这个错误：
java.lang.NumberFormatException: For input string: "length"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:492)
at java.lang.Integer.parseInt(Integer.java:527)
at javax.el.ArrayELResolver.toInteger(ArrayELResolver.java:378)
at javax.el.ArrayELResolver.getValue(ArrayELResolver.java:198)
at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:188)
at com.sun.el.parser.AstValue.getValue(AstValue.java:138)
at com.sun.el.parser.AstValue.getValue(AstValue.java:183)
at com.sun.el.parser.AstFunction.getValue(AstFunction.java:122)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:224)
at weblogic.servlet.jsp.ELHelper.evaluate(ELHelper.java:32)
at jsp_servlet._web_45_inf._jsp._manage.__managecompanybody._jsp__tag2(__managecompanybody.java:952)
at jsp_servlet._web_45_inf._jsp._manage.__managecompanybody._jspService(__managecompanybody.java:252)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:280)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:254)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:136)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:341)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:238)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:573)
at weblogic.servlet.internal.RequestDispatcherImpl.include(RequestDispatcherImpl.java:480)
at weblogic.servlet.jsp.PageContextImpl.include(PageContextImpl.java:162)
at jsp_servlet._web_45_inf._jsp._manage.__managebody._jspService(__managebody.java:1048)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:280)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:254)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:136)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:341)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:238)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:573)
at weblogic.servlet.internal.RequestDispatcherImpl.include(RequestDispatcherImpl.java:480)
at org.apache.taglibs.standard.tag.common.core.ImportSupport.acquireString(ImportSupport.java:347)
at org.apache.taglibs.standard.tag.common.core.ImportSupport.doEndTag(ImportSupport.java:204)
at jsp_servlet._web_45_inf._jsp._template.__template._jsp__tag2(__template.java:365)
at jsp_servlet._web_45_inf._jsp._template.__template._jspService(__template.java:247)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:280)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:254)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:136)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:341)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:238)
at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:573)
at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:272)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:264)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1208)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:992)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:939)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:855)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:751)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:844)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:280)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:254)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:136)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:341)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:25)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at cpm.tdk.iot.taglib.datagrid.export.ExcelExportFilter.doFilter(ExcelExportFilter.java:39)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at cpm.tdk.iot.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:27)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at cpm.tdk.iot.filter.EventDispatcherFilter.doFilter(EventDispatcherFilter.java:38)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at cpm.tdk.iot.filter.RequestUrlFilter.doFilter(RequestUrlFilter.java:31)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at cpm.tdk.iot.support.context.DevicesSecurityFilter.doFilter(DevicesSecurityFilter.java:82)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:79)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3367)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3333)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
at weblogic.servlet.provider.WlsSubjectHandle.run(WlsSubjectHandle.java:57)
at weblogic.servlet.internal.WebAppServletContext.doSecuredExecute(WebAppServletContext.java:2220)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2146)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2124)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1564)
at weblogic.servlet.provider.ContainerSupportProviderImpl$WlsRequestExecutor.run(ContainerSupportProviderImpl.java:254)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:295)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:254)
答案 0 :(得分：1)
您需要更改：
fn:length(form.attachment.bytes.length)
要：
fn:length(form.attachment.bytes)
您希望fn:length获取字节数组的长度，而不是长度的长度。