Automatically open the printer dialog after providing PDF download

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I am currently opening a pdf file in a new tab in my browser but I need to know how to open a printer dialog to print the pdf jasper report after pressing a commandButton

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独厮守ぢ

2020-11-28 11:59
With JasperReports

When using JasperReports, simply add this parameter to JasperReports exporter:
```
exporter.setParameter(JRPdfExporterParameter.PDF_JAVASCRIPT, "this.print();");
```
This basically instructs Adobe Acrobat to execute the script this.print() when opening the PDF. See also page 79-80 of Adobe Acrobat Scripting Guide. Below is an extract of relevance:

Printing PDF Documents

It is possible to use Acrobat JavaScript to specify whether a PDF document is sent to a printer or to a PostScript file. In either case, to print a PDF document, invoke the doc object’s print method. [...]

Without JasperReports

If you don't have control over generation of PDFs and thus can't manipulate it to add the mentioned script, an alternative is to change all the Java/JSF code accordingly so that the PDF file is idempotently available (i.e. the PDF file must be available by just a GET request rather than a POST request). This allows you to embed it in an <iframe> for which it's in turn possible to print its content by JavaScript during onload (keep CORS in mind though).

Simply put, the enduser must be able to download the desired PDF file by just entering its URL in browser's address bar. You can of course make use of GET request query string to specify parameters, allowing a bit more dynamicness. If it's "very large" data, then you can always let JSF put it in the HTTP session or DB and then pass an unique identifier around as request parameter so that the servlet can in turn obtain it from the very same HTTP session or DB.

Whilst possible with some nasty hacks, a JSF backing bean is simply insuitable for the job of idempotently serving a non-JSF response. You'd better use a "plain vanilla" servlet for this. You'll end up with much simpler code. Here's a kickoff example of such a servlet:
```
@WebServlet("/pdf")
public class PdfServlet extends HttpServlet {

    @Override    
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String foo = request.getParameter("foo");
        String bar = request.getParameter("bar");
        // ...

        // Now just use the same code as in your original bean *without* FacesContext.
        // Note that the HttpServletResponse is readily available as method argument!
        response.setContentType("application/pdf");
        // ...
    }

}
```
With this setup, it's available by http://localhost:8080/context/pdf?foo=abc&bar=xyz.

Once you get that part to work, then you just have to reference it in an <iframe> which uses JavaScript to print its own content window during its load event. You can do this in a JSF page, e.g. /pdf.xhtml:
```
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:ui="http://java.sun.com/jsf/facelets"
>
    <h:head> 
         <style>html, body { height: 100%; margin: 0; overflow: hidden; }</style>
    </h:head>
    <h:body>
        <iframe src="#{request.contextPath}/pdf?#{request.queryString}"
            width="100%" height="100%" onload="this.contentWindow.print()" />
    </h:body>
</html>
```
All you need to do in your JSF backing bean is to send a redirect to that page, if necessary with parameters in request query string (which will end up in #{request.queryString} so that the servlet can obtain them via request.getParameter(...)).

Here's a kickoff example:
```
<h:form target="_blank">
    <h:commandButton value="Generate report" action="#{bean.printPdf}" />
</h:form>
```
```
public String printPdf() {
    // Prepare params here if necessary.
    String foo = "abc";
    String bar = "xyz";
    // ...

    return "/pdf?faces-redirect=true" 
        + "&foo=" + URLEncoder.encode(foo, "UTF-8")
        + "&bar=" + URLEncoder.encode(bar, "UTF-8");
}
```
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北荒

2020-11-28 12:07
There is a <p:printer> Primefaces's component for that purpose.

Something like this might work, not tested though.
```
<h:form>
    <h:commandButton value="Print" type="button" icon="ui-icon-print">
        <p:printer target="pdf" />
    </h:commandButton>

    <p:media style="display:none;" id="pdf" value="/aPDF.pdf" />
</h:form>
```
Note :

<p:media> does have a print button to print the displayed pdf.

Edit :

You have to embed the pdf file inside an iframe and use the JavaScript print() function on it, or you can activate the auto-print function in the PDF itself. But it is definitely possible.

See this question on SO : Can a PDF file's print dialog be opened with Javascript?

How to Use JavaScript to Print a PDF
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清歌不尽

2020-11-28 12:21
You can't print a URL directly from JavaScript, you can only open the print dialog for the existing page - article and print API.

PDF is generated on the server and sent to the web-browser (as a separate "page") which has to decide how to process it - the user is usually asked if it wants to display or save the PDF.

To "automatically print" (i.e. open a print dialog) an HTML page you would just have something like this:
```
window.onload = function() {
  window.print();
};
```
But that can't be done for a PDF since it's not an HTML page.

To "automatically print" something other than an HTML page you would need to have a web-browser plug-in to handle PDFs from your server.

Another posibility is to write a GreaseMonkey user-script that would react on *.myserver.com/**.pdf and have it printed. Note: GreaseMonkey is a Mozilla Firefox plug-in.

Heavy weight option

You could accomplish your task by adding print support to your server application. Application requirements:
- It would have to be an Intranet application (self-hosted inside the user's network),
- Admin user would need to register network printers accessible from the server via a JSP page,
- A "print dialog" page where you would select a registered printer and on clicking the "Print" button send a "print" request, for example:
  
  /print?printer=printer1&doc=/reports/report1
I have seen a Java web application that supported this, but as you can see, it's not an easy task.

@Sujan Sivagurunathan

I tried combining the p:printer and p:media by replacing the image on the p:printer demo page with the PDF file from the p:media demo page:
```
// Replace this line:
<img id="j_idt18:image" src="/showcase/images/nature1.jpg?pfdrid_c=true" alt="">

// With this one:
<object **id="j_idt18:image"** style="display:none;" type="application/pdf" data="/showcase/resources/other/guide.pdf?pfdrid_c=true">Undefined</object>
```
When you click the Print button you get an empty page. If you omit the style="display:none;" and leave the PDF's height="300px" width="100%" you will get a small rectangle on the page print preview.

Eidt

Thank you, BalusC and Sujan. I agree, there is an option of embedding JavaScript inside the PDF, but that's usually disabled for security reasons.

I suppose the most browser-compatible and user-friendly way is to have a dedicated Print Preview pop-up window with an iframe showing the given PDF via GET request and a Print button to invoke the IFRAME's contentWindow.print().

It is generally a bad idea to just print a document without letting the user select the printer and configure it.
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Automatically open the printer dialog after providing PDF download

With JasperReports

Printing PDF Documents

Without JasperReports