【发布时间】：2021-03-23 08:49:04
【问题描述】：
我们正在将我们的 Web 应用程序从 Wicket 6.30 迁移到 Wicket 8.11.0。 作为第一步，放在类路径中的 jars 下面。
wicket-auth-roles-8.11.0.jar wicket-core-8.11.0.jar wicket-datetime-8.0.0-M7.jar wicket-extensions-8.11.0.jar wicket-request-8.11.0.jar wicket-util-8.11.0.jar wicketstuff-inmethod-grid-8.11.0.jar
解决了与 AjaxFallBackLink onClick() 方法相关的编译问题。 将方法签名更改为 public void onClick(Optional target)。
我们有一个 Html 页面
SettingsPanel.html
<?xml version="1.0" encoding="UTF-8"?>
<html xmlns:wicket="http://wicket.apache.org/dtds.data/wicket-xhtml1.4-strict.dtd" lang="en">
<wicket:panel>
<a href="#" wicket:id="saveSettingsLink"><img wicket:id="saveIcon" /></a>
</wicket:panel>
</html>
SettingsPanel.java
AjaxFallbackLink<Serializable> settingsLink = new AjaxFallbackLink<Serializable>("saveSettingsLink") {
private static final long serialVersionUID = 1L;
@Override
public void onClick(Optional<AjaxRequestTarget> target) {
//some logic
target.get().add(feedback);
}
};
Image img = new Image("saveIcon", new Model<Serializable>() {
private static final long serialVersionUID = 1L;
@Override
public Serializable getObject() {
return new PackageResourceReference(SettingsPanel.class,"save.png");
}
});
img.add(new AttributeModifier("title", new StringResourceModel("saveTitle", ColumnSettingsLinkPanel.this,new Model<String>())));
settingsLink.add(img);
使用上面的代码，在 Wicket 6.30 中，保存图像 (save.png) 会显示在页面上，当用户单击图像链接时，会触发 onlick(AjaxRequestTarget target)。 迁移到 Wicket 8.11.0 后，图像未显示在页面上，当用户单击图像链接时，触发 onClick(Optional target)，但目标值始终为 Empty。
下面是堆栈跟踪 错误 - DefaultExceptionMapper - 发生意外错误
java.util.NoSuchElementException: No value present
at java.base/java.util.Optional.get(Optional.java:148)
at com.csc.pts.web.ui.ColumnSettingsLinkPanel$3.onClick(SettingsPanel.java:98)
at org.apache.wicket.ajax.markup.html.AjaxFallbackLink.onClick(AjaxFallbackLink.java:122)
at org.apache.wicket.markup.html.link.Link.onRequest(Link.java:189)
at org.apache.wicket.core.request.handler.ListenerRequestHandler.internalInvoke(ListenerRequestHandler.java:306)
at org.apache.wicket.core.request.handler.ListenerRequestHandler.invoke(ListenerRequestHandler.java:255)
at org.apache.wicket.core.request.handler.ListenerRequestHandler.invokeListener(ListenerRequestHandler.java:215)
at org.apache.wicket.core.request.handler.ListenerRequestHandler.respond(ListenerRequestHandler.java:208)
at org.apache.wicket.core.request.handler.RequestSettingRequestHandler.respond(RequestSettingRequestHandler.java:78)
at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:912)
at org.apache.wicket.request.RequestHandlerExecutor.execute(RequestHandlerExecutor.java:65)
at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:283)
at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:253)
at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:221)
at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:262)
at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:204)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:286)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:834)
您能否就使此功能与 Wicket 8.11.0 版本一起使用所需的更改提供建议。
谢谢， 萨提亚
【问题讨论】：
-
你为什么首先使用 AjaxFallbackLink？如果您希望 AjaxRequestTarget 始终存在，只需使用 AjaxLink。
标签： wicket