使用方案：用户单击网站上的链接，会获得两种语言（德语和英语）的动态生成的PDF。
此代码有效。 generateCouponPdfOnClick创建一个包含pdf文件的ResourceStreamRequestHandler。
Link<Void> generatePdf = new Link<Void>("generatePdf") {
@Override
public void onClick() {
ResourceStreamRequestHandler requestHandler = generateCouponPdfOnClick(coupon, PDFLanguage.GERMAN);
getRequestCycle().scheduleRequestHandlerAfterCurrent(requestHandler);
}
};
现在，我想更改代码以获取一个弹出窗口（Wicket Modalwindow，此处为PdfDialogPage类），用户可以通过单击两个按钮之一来为PDF选择一种语言（德语/英语）。如果用户单击一个按钮，则应该关闭ModalWindow，并且应该构建并显示PDF。
这是修改后的代码：变量pdflanguageanguage包含所选语言，并由PdfDialogPage使用PageReferenz进行设置
AjaxLink<Void> generatePdf = new AjaxLink<Void>("generatePdf") {
@Override
public void onClick(final AjaxRequestTarget target) {
modalWindow.setPageCreator(() -> {
return new PdfDialogPage(getPage().getPageReference(), modalWindow);
});
modalWindow.setWindowClosedCallback((AjaxRequestTarget target1) -> {
ResourceStreamRequestHandler requestHandler = generateCouponPdfOnClick(coupon, pdflanguageanguage);
getRequestCycle().scheduleRequestHandlerAfterCurrent(requestHandler);
});
modalWindow.show(target);
};
当我单击链接时，将打开模态窗口。我选择语言，例如英文，并且在将“英文”写入变量pdflanguageanguage时，modalWindow关闭。仅此而已...没有生成PDF。 Wicket Ajax调试窗口告诉我以下日志：
</head>]]></header-contribution><evaluate><![CDATA[(function(){var settings = {"minWidth":200,"minHeight":200,"className":"w_blue","width":400,"height":100,"resizable":true,"src":"./wicket/page?6","mask":"semi-transparent","autoSize":false,"unloadConfirmation":true,"onClose":function() { Wicket.Ajax.ajax({"u":"./overviewCoupons?5-1.1-panel-modalWindow","c":"modalWindowb0"}); },"onCloseButton":function() { Wicket.Ajax.ajax({"u":"./overviewCoupons?5-1.0-panel-modalWindow","c":"modalWindowb0"});; return false; }};window.setTimeout(function(){
Wicket.Window.create(settings).show();
}, 0);
})();]]></evaluate></ajax-response>
INFO: returned focused element: javascript:;
INFO: returned focused element: javascript:;
INFO: Response processed successfully.
INFO: refocus last focused component not needed/allowed
INFO: focus removed from generatePdf5
INFO: focus set on _wicket_window_3
INFO: focus set on undefined
INFO: focus removed from undefined
ERROR: Wicket.Ajax.Call.failure: Error while parsing response: Error: Invalid XML: %PDF-1.4
%����
1 0 obj
<<
/Creator (Apache FOP Version 2.3)
/Producer (Apache FOP Version 2.3)
/CreationDate (D:20180808160110+02'00')
我相信Ajax与“ getRequestCycle（）。scheduleRequestHandlerAfterCurrent（requestHandler）;”之间存在问题。我如何一起使用这些。所以我将代码简化为：
AjaxLink<Void> generatePdf = new AjaxLink<Void>("generatePdf") {
@Override
public void onClick(final AjaxRequestTarget target) {
ResourceStreamRequestHandler requestHandler = generateCouponPdfOnClick(coupon, PDFLanguage.ENGLISH);
getRequestCycle().scheduleRequestHandlerAfterCurrent(requestHandler);
}
};
当我知道单击AjaxLink时，什么也没有发生，但是我得到了相同的Ajax日志错误输出。
如何将AjaxLink与ResourceStreamRequestHandler一起使用？
最佳答案
我以这种方式解决了类似的用例。
您需要来自here的Java类AjaxDownload
另外，您也可以使用以FileResourceStream作为输入的我的版本。
import lombok.extern.slf4j.Slf4j;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.behavior.AbstractAjaxBehavior;
import org.apache.wicket.request.handler.resource.ResourceStreamRequestHandler;
import org.apache.wicket.request.resource.ContentDisposition;
import org.apache.wicket.util.resource.FileResourceStream;
/**
* @author Sven Meier
* @author Ernesto Reinaldo Barreiro ([email protected])
* @author Jordi Deu-Pons ([email protected])
*/
@Slf4j
public class AJAXDownload extends AbstractAjaxBehavior {
private boolean addAntiCache;
private FileResourceStream fileResourceStream;
private String fileName;
public AJAXDownload() {
this(true);
}
public AJAXDownload(boolean addAntiCache) {
super();
this.addAntiCache = addAntiCache;
}
/**
* Call this method to initiate the download.
*/
public void initiate(AjaxRequestTarget target, FileResourceStream fileResourceStream, String fileName) {
this.fileResourceStream= fileResourceStream;
this.fileName = fileName;
String url = getCallbackUrl().toString();
if (addAntiCache) {
url = url + (url.contains("?") ? "&" : "?");
url = url + "antiCache=" + System.currentTimeMillis();
}
// the timeout is needed to let Wicket release the channel
target.appendJavaScript("setTimeout(\"window.location.href='" + url + "'\", 100);");
}
public void onRequest() {
try{
ResourceStreamRequestHandler handler = new ResourceStreamRequestHandler(fileResourceStream, fileName);
handler.setContentDisposition(ContentDisposition.ATTACHMENT);
getComponent().getRequestCycle().scheduleRequestHandlerAfterCurrent(handler);
} catch (Exception e){
log.error("Error while trying to download", e);
onErrorOccurred();
}
}
protected void onErrorOccurred(){}
}
如何使用？
您必须将AjaxDownload添加到您的表单中
form.add(ajaxDownload = new AJAXDownload());
在AjaxLink的onSubmit中，您可以调用：
File yourPdfFile = //create your pdf file;
final FileResourceStream resourceStream= new FileResourceStream(yourPdfFile);
ajaxDownload.initiate(target, resourceStream, "yourPDF.pdf");