Refresh/navigate current page while opening/downloading file in new tab/window

问题

I have a button which opens a new tab with a generated pdf-file. However, after I click on the button, I want to navigate to another page.

That means, after clicking on the button i want to open a new tab with the pdf and navigate to another page on the initial tab. I am using primefaces p:commandButton and tried with onclick="window.location.href='www.google.de'" but it does not work. However onclick="window.lalert('www.google.de')" does work.

This is my code:

<h:form id="transForm" target="_blank">
<p:commandButton  value="Zertifikat erstellen" ajax="false" 
                                label="Speichert die Anmeldung und erstellt ein Zertifikat im PDF-Format"
                                action="#{transportErfassen.generatePDFZertifikat()}"/>

</h:form>

generatePDFZertifikat() does create a pdf-File with following code, I think here is the issue:

    FacesContext facesContext = FacesContext.getCurrentInstance();
    ExternalContext externalContext = facesContext.getExternalContext();

    externalContext.setResponseContentType("application/pdf" );
    externalContext.setResponseHeader("Expires", "0");
    externalContext.setResponseHeader("Cache-Control","must-revalidate, post-check=0, pre-check=0");
    externalContext.setResponseHeader("Pragma", "public");
    externalContext.setResponseHeader("Content-disposition", "inline; filename=\"" + fileName +"\"");
    externalContext.setResponseContentLength(out.length);
    externalContext.addResponseCookie(Constants.DOWNLOAD_COOKIE, "true", new HashMap<String, Object>());

    //setze explizit auf OK
    externalContext.setResponseStatus(200);     

    OutputStream os = externalContext.getResponseOutputStream();
    os.write(out, 0, out.length);
    os.flush();

    facesContext.responseComplete();       
    facesContext.renderResponse();       

回答1:

You're basically trying to send 2 responses back to 1 request. This is not ever going to work in HTTP. If you want to send 2 responses back, you've got to let the client fire 2 requests somehow. You were already looking in the right direction for the solution, with little help of JavaScript it's possible to fire multiple requests on a single event (click). Your attempt in onclick is however not valid, the change of window.location on click of the submit button, right before the form submit, completely aborts the original action of the button, submitting the form.

Your best bet is to directly navigate to the result page which in turn invokes JavaScript window.open() on page load, pointing to the URL of the PDF file which you'd like to open. It's namely not possible to send some HTML/JS code along with the PDF file instructing a navigation (as that would obviously corrupt the PDF file). This also means, that you can't return the PDF directly to the form submit request. The code has to be redesigned in such way that the PDF can be retrieved by a subsequent GET request. The best way is to use a simple servlet. You could store the generated PDF temporarily on disk or in session, associated with an unique key, and pass that unique key as request pathinfo or parameter to the servlet in window.open() URL.

Here's a kickoff example:

Initial form:

<h:form>
    ...
    <p:commandButton ... action="#{bean.submit}" />
</h:form>

Bean:

public String submit() {
    File file = File.createTempFile("zertifikat", ".pdf", "/path/to/pdfs");
    this.filename = file.getName();

    // Write content to it.

    return "targetview";
}

Target view:

<h:outputScript rendered="#{not empty bean.filename}">
    window.open('#{request.contextPath}/pdfservlet/#{bean.filename}');
</h:outputScript>

PDF servlet (nullchecks etc omitted for brevity; Java 7 assumed for Files#copy()):

@WebServlet("/pdfservlet/*")
public class PdfServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        File file = new File("/path/to/pdfs", request.getPathInfo().substring(1));
        response.setHeader("Content-Type", "application/pdf");
        response.setHeader("Content-Length", String.valueOf(file.length()));
        response.setHeader("Content-Disposition", "inline; filename=\"zertifikat.pdf\"");
        Files.copy(file.toPath(), response.getOutputStream());
    }

}

回答2:

As BalusC said, Refresh/navigate current page and opening downloading file are two different responses, there must be two resquests. I encountered a similar problem. I solved it with jsf ajax successfully.

Here's part of my code:

XHTML：

<h:commandButton id="download-button" class="download-button"
    value="download">
<f:ajax event="click" execute="@form" render=":msg-area"
    listener="#{myController.checkForDownload}" onevent="checkCallBack" />
</h:commandButton>
<h:commandButton id="download-button2" class="download-button2"
    value="download" style="display: none;"
    action="#{myController.download}">
</h:commandButton>

Javascript:

function checkCallBack(data) {
    var ajaxStatus = data.status;
    switch (ajaxStatus) {
    case "begin":
        break;
    case "complete":
        break;
    case "success":
        document.getElementById('download-form:download-button2').click();
        break;
    }
}

download-button renders a message area on page and download-button2 triggers a download method. they are two different requests. When the first request completed, the second request will be triggered.

来源：https://stackoverflow.com/questions/18333327/refresh-navigate-current-page-while-opening-downloading-file-in-new-tab-window