Why is it not possible to combine a jsp include tag with an <%= ... %> expression?
<jsp:include page="pages/<%= element.convertToLowercase() %>.jsp"></jsp:include>
The element.convertToLowercase() returns the page that should be displayed.
Instead I'm getting the error Failed to decode [/pages/<%= element.convertToLowercase() %>.jsp] because the % character must be followed by two hexademical digits.
My suspicion is that the <%= expression is being red as part of the URL and not as an jsp expression.
How can this be implemented instead?
Full stacktrace:
java.lang.IllegalArgumentException: Failed to decode [/pages/<%= element.convertToLowercase() %>.jsp] because the % character must be followed by two hexademical digits at org.apache.tomcat.util.buf.UDecoder.URLDecode(UDecoder.java:431) at org.apache.catalina.core.ApplicationContext.getRequestDispatcher(ApplicationContext.java:429) at org.apache.catalina.core.ApplicationContextFacade.getRequestDispatcher(ApplicationContextFacade.java:227) at org.apache.catalina.connector.Request.getRequestDispatcher(Request.java:1417) at org.apache.catalina.connector.RequestFacade.getRequestDispatcher(RequestFacade.java:614) at org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:952) at org.apache.jsp.index_jsp._jspService(index_jsp.java:285) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:467) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:378) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:326) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:832)