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File Upload

You could associate the upload feature to a component, such as Button, Toolbarbutton or Menuitem. In other words, you could make a button or a menu item to upload a file when the user clicks on it.

The implementation is straightaway:

  1. Assign the upload attribute to true for the component used to upload a file
  2. Assign an event listener to the component for the onUpload event[1]

For example,

	void upload(UploadEvent event) { 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);
		} else {"Not an image: "+media, "Error", Messagebox.OK, Messagebox.ERROR);
	<button label="Upload" upload="true" onUpload="upload(event)"/>
	<vlayout id="pics" />

You could control the maximal allowed number of files, the maximal allowed size and other information by use of Button.setUpload(String).

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

  1. If you enabled the use of event threads, you could use Fileupload.get() and related. For more information, please refer to the Event Thread section.

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 calendar.pdf"
onClick='"/resources/calendar.pdf", 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

Last Update : 2020/4/7

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Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.