PrimeFaces 3.2简单的FileUpload，在上传之前获取所选文件信息，如文件名

Question

I am using (Java Server Faces 2.2) Primefaces 3.2 simple file upload controller. I need to access file info before upload. What listener can I use when a file is selected & how do i get file info in the ManagedBean before initiating the upload

Answer 1

The tag does not support any ajax behavior event, so the only thing you can do is to call a method before the upload starts using the "onstart" attribute of that fires when upload starts. Using a remote command you can do something like:

<p:remoteCommand name="beforeUpdate" partialSubmit="true" process="@this" 
                                 actionListener="#{myBean.doBefore}" value="" />

add call to remote command to the fileUpload

<p:fileUpload fileUploadListener="#{itemImportDialogController.uploadListener}" 
         mode="advanced" multiple="true" onstart="beforeUpdate()"
         styleClass="importItems" update=":itemImportView:fileForm" style="margin: 10px 0"/>

and in the bean add a method like this

public void doBefore() {
     //DO SOME WORK
}

About file name you can retrieve it only when the file is being uploaded

public void uploadListener(FileUploadEvent event) {

    UploadedFile file = event.getFile();
    //DO SOMETHING
}

because there is no ajax interaction possible between the component and the server before this. So I'm sorry but is not possible.

By the way you could try to manage this through jQuery catching the event with something like

$('input[type=file]').change(function() { 
    //GET THE FILE AND SUBMIT IT TO THE SERVER WITH AJAX CALL 
});