在页面上找不到Wicket图像组件
当我试图显示一个项目列表时，我会遇到以下问题。对于每个项目，我必须显示一个通过Wicket WebResource动态加载的图像。这些项目一步一步地加载，每次用户滚动，使用Ajax滚动。
错误2011-04-19 09:58:18,000 btpool0 0-1 org.apache.wicket.RequestCycle.logRuntimeException (host=，request=，site=)：org.apache.wicket.WicketRuntimeException:在页面com.webapp.document.pages.DocumentListPageid上找不到的组件
=1侦听器接口= RequestListenerInterface name=IResourceListener，method=public抽象空org.apache.wicket.IResourceListener.onResourceRequested()
org.apache.wicket.protocol.http.request.InvalidUrlException: org.apache.wicket.WicketRuntimeException:在页面com.webapp.document.pages.DocumentListPageid =1侦听器接口= RequestListenerInterface name=IResourceListener中找不到组件com.webapp.document.pages.DocumentListPageid，抽象org.apache.wicket.IResourceListener.onResourceRequested() at org.apache.wicket.protocol.http.WebRequestCycleProcessor.resolve(WebRequestCycleProcessor.java:262) at org.apache.wicket.RequestCycle.step(RequestCycle.java:1310) at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1428) at org.apache.wicket.RequestCycle.request(RequestCycle.java:545) at org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java：在org.apache.wicket.protocol.http.WicketFilter$$EnhancerByGuice$$51619816.CGLIB$doGet$6() at org.apache.wicket.protocol.http.WicketFilter$$EnhancerByGuice$$51619816$$FastClassByGuice$$6d42bf5d.invoke() at com.google.inject.internal.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) at com.google.inject.internal.InterceptorStackCallback$InterceptedMethodInvocation.proceed(InterceptorStackCallback.java:64) at com.freiheit.monitoring.PerformanceMonitoringMethodInterceptor.invoke(PerformanceMonitoringMethodInterceptor.java:115) at com.google.inject.internal。InterceptorStackCallback$InterceptedMethodInvocation.proceed(InterceptorStackCallback.java:64) at com.google.inject.internal.InterceptorStackCallback.intercept(InterceptorStackCallback.java:44) at org.apache.wicket.protocol.http.WicketFilter$$EnhancerByGuice$$51619816.doGet() at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:312) at org.apache.wicket.protocol.http.WicketFilter$$EnhancerByGuice$$51619816.CGLIB$doFilter$4()
如何解决这个问题呢？
下面是代码中负责添加图像的部分：
previewLink.add(createThumbnailSmall("imageThumbnail", documentModel));在……里面
createThumbnailSmall(final String id, final IModel<BaseDocument> documentModel) {
// thumbnailResource is an object that contains the path of the image
if (thumbnailResource != null) {
final WebResource resource = getWebResource(thumbnailResource);
final Image image = new Image(id, resource);
return image;
}
return new InvisibleContainer(id);
}
WebResource getWebResource(final DocumentResource documentResource) {
return new WebResource() {
private static final long serialVersionUID = 1L;
@Override
public IResourceStream getResourceStream() {
return new BaseStreamResource(documentResource);
}
};
}其中BaseStreamResource如下：
public class BaseStreamResource extends AbstractResourceStream {
private InputStream _fileInputStream = null;
private DocumentResource _resource = null;
public BaseStreamResource(final DocumentResource documentResource) {
_resource = documentResource;
}
@Override
public InputStream getInputStream() throws ResourceStreamNotFoundException {
if (_fileInputStream == null) {
try {
if (_resource == null) {
throw new ResourceStreamNotFoundException("Resource was null");
}
_fileInputStream = _resource.getFileInputStream();
} catch (final ResourceNotAvailableException ex) {
throw new ResourceStreamNotFoundException(ex);
}
}
return _fileInputStream;
}在HTML中：
<a wicket:id="linkToPreview" href="#">
<img wicket:id="imageThumbnail" alt="Attachment"></img></a>回答 2
Stack Overflow用户
发布于 2011-04-28 08:30:01
以下解决方案解决了这个问题：
- 扩展WebResource类
- 将扩展类添加到应用程序共享资源
中
例如：
public class MyWebResource extends WebResource {
final ValueMap map = new ValueMap();
@Override
public IResourceStream getResourceStream() {
String fileName = getFileName();
File file = new File(basePath, fileName);
if (!file.exists()) {
LOG.error("File does not exist: " + file);
throw new IllegalStateException("File does not exist: " + file);
}
return new FileResourceStream(file);
}
public final void addResource() {
Application.get().getSharedResources().add(getClass().getName(), this);
}
protected String getFileName() {
return getParameters().getString("id");
}
public final String urlFor(final String fileName) {
final ResourceReference resourceReference = new ResourceReference(getClass().getName());
final String encodedValue = WicketURLEncoder.QUERY_INSTANCE.encode(fileName);
map.add("id", encodedValue);
final CharSequence result = RequestCycle.get().urlFor(resourceReference, map);
if (result == null) {
throw new IllegalStateException("The resource was not added! "
+ "In your Application class add the following line:"
+ "MyConcreteResource.INSTANCE.addResource()");
}
String absoluteUrl = RequestUtils.toAbsolutePath(result.toString());
return absoluteUrl;
}
}在Application中，在init()中，我将MyWebResource添加到共享资源中：
public void init() {
...
new MyWebResource().addResource();
...
}Stack Overflow用户
发布于 2011-04-19 11:28:20
添加的代码并没有真正为我添加任何线索，但也许我可以帮助缩小它的范围。
堆栈跟踪包含对com.webapp.document.pages.DocumentListPage的引用，该引用可能会调用您发布的一些代码。错误表示错误的url，所以调试到该类中，添加调试打印，并查看包含url的任何字段的值都是值得的。
它甚至可能有助于修改DocumentListPage中的代码(可能暂时用于调试)，以便在异常被捕获时捕获org.apache.wicket.protocol.http.request.InvalidUrlException并添加调试打印。
这不是一个真正的答案，但它太大，不能发表评论，也许它会帮助你接近一个答案。
https://stackoverflow.com/questions/5714229
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