Java：检票口无法找到组件答案

【问题标题】：Java: wicket unable to find componentJava：检票口无法找到组件
【发布时间】：2018-02-28 23:26:17
【问题描述】：

尝试重新打包其他开发人员维护的内容并遇到检票口组件问题。老实说，只是在正确的方向上寻找一个点来缩小这里实际发生的情况。我无权访问我已反编译的源代码仅编译的战争。这似乎在他们完美的环境中运行时可以正常运行，但我需要运行一个稍微不同的 java 版本。

从这个错误看来，它只是找不到“功能”组件。我怎样才能回溯这个？反编译 ServerStatusPage 的类我只将“功能”视为变量。有没有一种快速的方法可以让我暂时删除状态页面的违规区域并重新打包war文件？当我尝试时，我最终遇到了更多问题，说我排除了应该存在的组件。

运行时的完整错误如下：

2018-02-28 23:04:02,603 ERROR [wicket.RequestCycle] (default task-23) Unable to find component with id 'feature' in [MarkupContainer [Component id = 0, page = extensis.esp.webadmin.pages.serverstatus.ServerStatusPage, path = 7:features:0.ListItem, isVisible = true, isVersioned = true]]. This means that you declared wicket:id=feature in your markup, but that you either did not add the component to your page at all, or that the hierarchy does not match.
[markup = vfs:/content/ROOT.war/WEB-INF/classes/extensis/esp/webadmin/pages/serverstatus/ServerStatusPage.html, index = 34, current = '<span wicket:id="feature">' (line 52, column 6)]: wicket.markup.MarkupException: Unable to find component with id 'feature' in [MarkupContainer [Component id = 0, page = extensis.esp.webadmin.pages.serverstatus.ServerStatusPage, path = 7:features:0.ListItem, isVisible = true, isVersioned = true]]. This means that you declared wicket:id=feature in your markup, but that you either did not add the component to your page at all, or that the hierarchy does not match.
[markup = vfs:/content/ROOT.war/WEB-INF/classes/extensis/esp/webadmin/pages/serverstatus/ServerStatusPage.html, index = 34, current = '<span wicket:id="feature">' (line 52, column 6)]
    at wicket.markup.MarkupStream.throwMarkupException(MarkupStream.java:290) [wicket.jar:]
    at wicket.MarkupContainer.renderNext(MarkupContainer.java:1381) [wicket.jar:]
    at wicket.MarkupContainer.renderComponentTagBody(MarkupContainer.java:982) [wicket.jar:]
    at wicket.MarkupContainer.onComponentTagBody(MarkupContainer.java:917) [wicket.jar:]
    at wicket.Component.renderComponent(Component.java:1712) [wicket.jar:]
    at wicket.MarkupContainer.onRender(MarkupContainer.java:927) [wicket.jar:]
    at wicket.Component.render(Component.java:1526) [wicket.jar:]
    at wicket.markup.html.list.ListView.renderItem(ListView.java:680) [wicket.jar:]
    at wicket.markup.html.list.ListView.onRender(ListView.java:641) [wicket.jar:]
    at wicket.Component.render(Component.java:1526) [wicket.jar:]
    at wicket.MarkupContainer.renderNext(MarkupContainer.java:1334) [wicket.jar:]
    at wicket.MarkupContainer.renderComponentTagBody(MarkupContainer.java:982) [wicket.jar:]
    at wicket.MarkupContainer.onComponentTagBody(MarkupContainer.java:917) [wicket.jar:]
    at wicket.Component.renderComponent(Component.java:1712) [wicket.jar:]
    at wicket.MarkupContainer.onRender(MarkupContainer.java:927) [wicket.jar:]
    at wicket.Component.render(Component.java:1526) [wicket.jar:]
    at wicket.MarkupContainer.renderNext(MarkupContainer.java:1334) [wicket.jar:]
    at wicket.MarkupContainer.renderAll(MarkupContainer.java:944) [wicket.jar:]
    at wicket.Page.onRender(Page.java:864) [wicket.jar:]
    at wicket.Component.render(Component.java:1526) [wicket.jar:]
    at wicket.Page.renderPage(Page.java:413) [wicket.jar:]
    at wicket.request.target.component.BookmarkablePageRequestTarget.respond(BookmarkablePageRequestTarget.java:226) [wicket.jar:]
    at wicket.request.compound.DefaultResponseStrategy.respond(DefaultResponseStrategy.java:49) [wicket.jar:]
    at wicket.request.compound.AbstractCompoundRequestCycleProcessor.respond(AbstractCompoundRequestCycleProcessor.java:66) [wicket.jar:]
    at wicket.RequestCycle.doProcessEventsAndRespond(RequestCycle.java:902) [wicket.jar:]
    at wicket.RequestCycle.processEventsAndRespond(RequestCycle.java:929) [wicket.jar:]
    at wicket.RequestCycle.step(RequestCycle.java:1010) [wicket.jar:]
    at wicket.RequestCycle.steps(RequestCycle.java:1084) [wicket.jar:]
    at wicket.RequestCycle.request(RequestCycle.java:454) [wicket.jar:]
    at wicket.protocol.http.WicketServlet.doGet(WicketServlet.java:219) [wicket.jar:]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:687) [jboss-servlet-api_3.1_spec-1.0.0.Final.jar:1.0.0.Final]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [jboss-servlet-api_3.1_spec-1.0.0.Final.jar:1.0.0.Final]
    at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174) [undertow-servlet-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793) [undertow-core-1.3.15.Final.jar:1.3.15.Final]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [rt.jar:1.8.0_141]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [rt.jar:1.8.0_141]
    at java.lang.Thread.run(Thread.java:748) [rt.jar:1.8.0_141]

正在处理的html文件是：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <meta http-equiv="refresh" content="15">
    <meta http-equiv="Cache-Control" content="no-store, no-cache, max-age=0, must-revalidate">
    <meta http-equiv="expires" content="0">
    <meta http-equiv="pragma" content="NO-CACHE">
    <meta http-equiv="Content-Type" CONTENT="text/html; charset=utf-8">

    <script language="JavaScript"><!--
        function setIFrameContents(frameName, contents) {
             var iFrame = window.frames[frameName]; 
             iFrame.document.open();     
             iFrame.document.write(contents); 
             iFrame.document.close();
        }
    //--></script>


    <title wicket:id="pagetitle">Status</title>
    <link rel="stylesheet" type="text/css" href="main.css" />
</head>

<body>

    <div class="main">

        <div class="header"></div>

        <div class="nav-and-content">

            <div class="navbar">
                <span wicket:id="navBar"></span>                                                    
            </div> <!--end nav bar div-->

            <div class="lockButton">
                <form wicket:id="lockUnlockForm">
                    <input wicket:id="lockButton" type="image" src=""/>
                    <input wicket:id="unlockButton" type="image" src=""/>                   
                </form>
            </div>

            <div class="content">
                <p>
                    <span class="title" wicket:id="title">Status</span>
                    <span class="error" wicket:id="feedback">Error verbiage if any goes here.</span>                    
                </p>

                <br/>

                <span wicket:id="features">
                    <span wicket:id="feature"></span>
                </span>

            </div> <!-- end content -->

        <div class="clear"></div>           

        </div> <!-- end nav-and-content -->



        <div class="footer"></div>

        <div class="langs" wicket:id="localeSelectPanel"></div>

    </div> <!--end main div-->

</body>
</html>

感谢并原谅我对其中的一些无知。

【问题讨论】：

标签： java wicket war

【解决方案1】：

使用 ListView 的代码应如下所示：

ListView lv = new ListView("features", listOfFeatures) {
   @Override protected void onPopulate(ListItem<Feature> li) {
       li.add(new FeaturePanel("feature", li.getModel()));
   }

}

在您的异常消息组件中，0 是 ListItem。似乎由于某种原因行 li.add(new FeaturePanel("feature")); 没有被执行，所以 0 没有 ID 为 feature 的孩子。

由于您没有附加调试器的源代码，因此不会有太大帮助，但至少您将能够看到组件树中的内容。只需在 MarkupContainer.renderNext(MarkupContainer.java:1381) 处设置断点，然后检查 this 是 ID=0 的 ListItem 时 children 成员字段的值是多少。

从类名上我可以说这是 Wicket 1.3 或更早的版本，这是 Wicket 的非常旧的版本！

【讨论】：

谢谢！我会尝试并报告:) 也希望下一个版本包括一些更新版本：/