File Download In ADF

It is common requirement in many projects to have file download facility.
File download facility can be achieved by many means, but in 11g + versions we have one very good component
to handle file download facility very quickly.

In 11g + versions we have one listener component called fileDownloadActionListener. Which can be triggered from any command related components like commandButton , commandLink etc.

It has three parameters filename, contentType, method.

filename : It is used to display the file name in response

method:   The method will be present in managed bean. It is used to handle the file download related activities. Signature of this method is

public void <method name> (FacesContext context, OutputStream out) throws IOException
                {
                    ...... your code...
                 }

contentType: It is used to specify the content type.(like it is word document or pdf document etc.)

In the below example I have used fileDownloadActionListener with commandLink.


<af:commandLink id="cl1" text="#{row.fileName}"
                                              partialSubmit="true"
                                              binding="#{fileDownloadBean.downloadLink}">
                                <af:fileDownloadActionListener filename="#{row.fileName}"
                                                               method="#{fileDownloadBean.download}" ></af:fileDownloadActionListener>
                              </af:commandLink>

The method referred is



    public void download(FacesContext context,
                         OutputStream out) throws IOException {
        File f =
            new File(this.directoryPath.getValue().toString() + "/" + downloadLink.getText());
        FileInputStream fis;
        byte[] b;
        try {
            fis = new FileInputStream(f);

            int n;
            while ((n = fis.available()) > 0) {
                b = new byte[n];
                int result = fis.read(b);
                out.write(b, 0, b.length);
                if (result == -1)
                    break;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
         out.flush();
    }

So whatever file I want to download it will be downloaded using this listener. The coding type will be least one.

Please comment...