ファイルダウンロードの中身の送信

public class SampleDownloadAction extends DownloadAction {
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) throws Exception {

        StreamInfo info = null;
        InputStream stream = null;
        try {
            info = getStreamInfo(mapping, form, request, response);
            stream = info.getInputStream();
        } catch (Exception ex) {
            // ファイルが無い場合などに引っかかる。エラー表示処理を入れてください。

        } finally {
            if (stream != null) {
                stream.close();
            }
        }
        
        // 以下はコピー
        try {
            response.setContentType(info.getContentType());
            copy(stream, response.getOutputStream());
        } catch (Exception ex) {
            // ダウンロード中にエラー。エラー画面表示は不可。
            
        } finally {
            if (stream != null) {
                stream.close();
            }
        }
        return null;
    }

    protected StreamInfo getStreamInfo(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) throws Exception {
        String contentType = "application/octet-stream-dummy";
        File file = new File(mapping.getParameter());
        return new FileStreamInfo(contentType, file);
    }
}