File Upload

File Upload with Servlet Thread

When the event thread is disable (default), it is recommended to use org.zkoss.zul.Button, org.zkoss.zul.Toolbarbutton or org.zkoss.zul.Menuitem with upload=”true” instead. 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)"/>
    <toolbarbutton label="Upload" upload="true" onUpload="upload(event)"/>
    <vbox id="pics" />
</zk>

If you prefer to use a dialog (org.zkoss.zul.Fileupload#get()), please take a look at ZK Component Reference: Fileupload for more inormation.

File Upload with Event Thread

If the event thread is disabled, the developer can use org.zkoss.zul.Button or org.zkoss.zul.Toolbarbutton with upload=”true” instead. They behave the same no matter if the event thread is disabled or not.

However, if the event thread is enabled, you can get uploaded Media returned by org.zkoss.zul.Fileupload#get() and other overloadded static methods.

<zk>
    <button label="Upload">
    <attribute name="onClick">{
        org.zkoss.util.media.Media[] media = Fileupload.get(-1);
        if (media != null) {
            for (int i = 0; i < media.length; i++) {
                if (media[i] instanceof org.zkoss.image.Image) {
                    org.zkoss.zul.Image image = new org.zkoss.zul.Image();
                    image.setContent(media[i]);
                    image.setParent(pics);
                } else {
                    Messagebox.show("Not an image: "+media[i], "Error", Messagebox.OK, Messagebox.ERROR);
                    break; //not to show too many errors
                }
            }
        }
    }</attribute>
    </button>
    <vbox id="pics" />
</zk>

As shown, org.zkoss.zul.Fileupload#get(int) won’t return until an end user uploads the files (and/or closes the dialog).

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