Question

错误名称：javax.servlet.jsp.el.ELException: No function is mapped to the name "fn:length"

错误详细信息：javax.servlet.jsp.el.ELException: No function is mapped to the name "fn:length"
at org.apache.commons.el.Logger.logError(Logger.java:481)
at org.apache.commons.el.Logger.logError(Logger.java:498)
at org.apache.commons.el.Logger.logError(Logger.java:525)
at org.apache.commons.el.FunctionInvocation.evaluate(FunctionInvocation.java:133)
at org.apache.commons.el.BinaryOperatorExpression.evaluate(BinaryOperatorExpression.java(Compiled Code))
at org.apache.commons.el.ExpressionEvaluatorImpl.evaluate(ExpressionEvaluatorImpl.java(Compiled Code))
at org.apache.commons.el.ExpressionEvaluatorImpl.evaluate(ExpressionEvaluatorImpl.java(Inlined Compiled Code))
at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java(Compiled Code))
at com.ibm._jsp._listMessage._jspx_meth_c_when_2(_listMessage.java:752)
at com.ibm._jsp._listMessage._jspx_meth_c_choose_2(_listMessage.java:781)
at com.ibm._jsp._listMessage._jspService(_listMessage.java:232)
at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java(Compiled Code))
at javax.servlet.http.HttpServlet.service(HttpServlet.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java(Compiled Code))
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java(Compiled Code))
at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java(Compiled Code))
at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java(Inlined Compiled Code))
at com.ibm.ws.jsp.webcontainerext.JSPExtensionServletWrapper.handleRequest(JSPExtensionServletWrapper.java(Compiled Code))
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.forward(WebAppRequestDispatcher.java(Compiled Code))
at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java(Compiled Code))
at org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java(Compiled Code))
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java(Compiled Code))
at org.apache.struts.action.ActionServlet.process(ActionServlet.java(Inlined Compiled Code))
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java(Compiled Code))
at javax.servlet.http.HttpServlet.service(HttpServlet.java(Compiled Code))
at javax.servlet.http.HttpServlet.service(HttpServlet.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java(Compiled Code))
at org.springframework.web.filter.CharacterEncodingFilter.

Answer 1

LZ你用了jstl的函数库巴，要引入函数库的头才可以用

<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>

${fn:length(list)}

Answer 2

这是你的EL表达式中的错误，你是自定义了一个标签吧，仔细看看的的“No function is mapped to the name "fn:length"
”

fn:length在哪里出现过。。。。