Java for Web学习笔记（三八）：自定义tag（6）一些注意

引入的base.jspf

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ page import="cn.wei.flowingflying.customer_support.Ticket,cn.wei.flowingflying.customer_support.Attachment" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<%@ taglib prefix="wrox" uri="http://www.wrox.com/jsp/tld/wrox" %>
<%@ taglib prefix="template" tagdir="/WEB-INF/tags/template" %>

会报错：

org.apache.jasper.JasperException: /WEB-INF/tags/template/loggedOut.tag (line: 4, column: 1) /WEB-INF/jsp/base.jspf (line: 1, column: 9) <%@ page directive cannot be used in a tag file

需要修订为

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<%@ taglib prefix="wrox" uri="http://www.wrox.com/jsp/tld/wrox" %>
<%@ taglib prefix="template" tagdir="/WEB-INF/tags/template" %>

在jsp的注释中，尽可能不要写入<>

<!-- At this point the attribute is specified within the tag body content, so to specify the real tag body
content you need to use the <jsp:body> tag.  -->

会报错：
org.apache.jasper.JasperException: /WEB-INF/tags/template/loggedOut.tag (line: 10, column: 1) Must use jsp:body to specify tag body for <template:main if jsp:attribute is used.

改为：
<!-- At this point the attribute is specified within the tag body content, so to specify the real tag body
content you need to use the jsp:body tag.  -->

jsp:attribute和jsp:body之间不要加入注释

<template:main htmlTitle="${htmlTitle}" bodyTitle="${bodyTitle}">
<jsp:attribute name="headContent">
<link rel="stylesheet" href="<c:url value="/resource/stylesheet/login.css" />" />
</jsp:attribute>
<jsp:attribute name="navigationContent" />
<!-- At this point the attribute is specified within the tag body content, so to specify the real tag body
content you need to use the jsp:body tag. -->
<jsp:body>
<jsp:doBody />
</jsp:body>
</template:main>

这会报错：

十一月 30, 2016 9:07:18 上午 org.apache.catalina.core.ApplicationDispatcher invoke
严重: Servlet.service() for servlet jsp threw exception
org.apache.jasper.JasperException: /WEB-INF/tags/template/loggedOut.tag (line: 10, column: 1) Must use jsp:body to specify tag body for <template:main if jsp:attribute is used.
at org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:41)
at org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:275)
at org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:91)
at org.apache.jasper.compiler.Parser.parseJspAttributeAndBody(Parser.java:1044)
at org.apache.jasper.compiler.Parser.parseOptionalBody(Parser.java:1004)
at org.apache.jasper.compiler.Parser.parseCustomTag(Parser.java:1281)
at org.apache.jasper.compiler.Parser.parseElements(Parser.java:1460)
at org.apache.jasper.compiler.Parser.parse(Parser.java:139)
at org.apache.jasper.compiler.ParserController.doParse(ParserController.java:227)
at org.apache.jasper.compiler.ParserController.parse(ParserController.java:100)
at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:199)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:336)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:323)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:585)
at org.apache.jasper.servlet.JspServletWrapper.loadTagFile(JspServletWrapper.java:246)
at org.apache.jasper.compiler.TagFileProcessor.loadTagFile(TagFileProcessor.java:587)
at org.apache.jasper.compiler.TagFileProcessor.access$000(TagFileProcessor.java:50)
at org.apache.jasper.compiler.TagFileProcessor$TagFileLoaderVisitor.visit(TagFileProcessor.java:674)
at org.apache.jasper.compiler.Node$CustomTag.accept(Node.java:1536)
at org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2376)
at org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2428)
at org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2434)
at org.apache.jasper.compiler.Node$Root.accept(Node.java:464)
at org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2376)
at org.apache.jasper.compiler.TagFileProcessor.loadTagFiles(TagFileProcessor.java:692)
at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:229)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:336)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:323)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:585)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:363)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:720)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:466)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
at cn.wei.flowingflying.customer_support.LoginServlet.doGet(LoginServlet.java:55)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)

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