File Upload and Download

File Upload

Button, Toolbarbutton and Menuitem support file upload out-of-box In other words. You just need to enable it with the steps below:

1. Specify upload attribute with true to enable file upload
2. Assign an event listener to the component for the onUpload event

For example,

<zk>
	<zscript>
	void upload(UploadEvent event) {
		org.zkoss.util.media.Media media = event.getMedia();
		if (media instanceof org.zkoss.image.Image) {
			org.zkoss.zul.Image image = new org.zkoss.zul.Image();
			image.setContent( (org.zkoss.image.Image) media);
			image.setParent(pics);
		} else {
			Messagebox.show("Not an image: "+media, "Error", Messagebox.OK, Messagebox.ERROR);
		}
	}
	</zscript>
	<button label="Upload" upload="true" onUpload="upload(event)"/>
	<vlayout id="pics" />
</zk>

You can control the maximal allowed number of files, the maximal allowed size, and other options. Please refer to org.zkoss.zul.Button.setUpload().

<menupopup>
    <menuitem label="Upload" upload="true,maxsize=-1,native"/>
</menupopup>

There is more options for upload attributes, please see ZK Component Reference/Essential Components/Button#Upload.

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Open File Upload Dialog

If you want the file upload on another component rather than those components above (Button, Toolbarbutton, Menu), you can call FileUpload.get() in an event listener.

Here is an example:

    <a iconSclass="z-icon-upload" ...
       apply="org.zkoss.reference.developer.uipattern.UploadComposer"/>

public class UploadComposer extends SelectorComposer {

    @Listen(Events.ON_CLICK + "= a")
    public void handleUpload(MouseEvent e) {
        Fileupload.get(1, new EventListener<UploadEvent>() {
            public void onEvent(UploadEvent event) throws Exception {
                Media[] medias = event.getMedias();
                System.out.println("upload " +  medias[0].getName());
            }
        });
    }
}

File Download

Filedownload provides a set of utilities to prompt a user for downloading a file from the server to a local folder. For example,

<button label="Download a file" onClick='Filedownload.save("~./zklogo.png", null);'/>

The file could be a static resource, an input stream, a file, a URL and others. Please refer to ZK Component Reference and Filedownload for more information.

Version History

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