java如何在downloadLink中使用wicket StringResourceModel

Question

我有一个可以工作的按钮：

    Button options = new Button("sheets", new StringResourceModel("sheets", null)) {

        private static final long serialVersionUID = 1L;

        @Override
        public void onSubmit() {
            setResponsePage(new TournamentOptionsPage(tournament, table) {

                private static final long serialVersionUID = 1L;
            });
        }
    };

现在我想用downloadLink替换这个按钮：

        add(new DownloadLink("sheets", new AbstractReadOnlyModel<File>() {
            private static final long serialVersionUID = 1L;

            @Override
            public File getObject() {
                File tempFile;
                try {
                    tempFile = PdfFactory.createSheets(WicketApplication.getSheetsPath(),
                            tournamentService.getSchedule(table, tournament), table);
                } catch (Exception e) {
                    e.printStackTrace();
                    throw new RuntimeException(e);
                }
                return tempFile;
            }
        }, new StringResourceModel("sheets", null)).setCacheDuration(Duration.NONE).setDeleteAfterDownload(true));

但我在这里遇到了StringResourceModel的问题，当我推链接时，我得到了一个例外：

Caused by: java.util.MissingResourceException: Unable to find property: 'sheets'
    at org.apache.wicket.Localizer.getString(Localizer.java:239)
    at org.apache.wicket.Localizer.getString(Localizer.java:170)
    at org.apache.wicket.model.StringResourceModel.getString(StringResourceModel.java:425)
    at org.apache.wicket.model.StringResourceModel.getString(StringResourceModel.java:400)
    at org.apache.wicket.model.StringResourceModel.load(StringResourceModel.java:583)
    at org.apache.wicket.model.StringResourceModel.load(StringResourceModel.java:182)
    at org.apache.wicket.model.LoadableDetachableModel.getObject(LoadableDetachableModel.java:119)
    at org.apache.wicket.markup.html.link.DownloadLink.onClick(DownloadLink.java:151)
    at org.apache.wicket.markup.html.link.Link.onLinkClicked(Link.java:188)

为什么这不起作用