对飞碟使用自定义字体会导致PDF损坏

Question

我有一个用飞碟生成的工作PDF。然而，当我现在想添加自定义字体时，生成的PDF会损坏。浏览器没有下载文件，而是显示各种奇怪的符号。

通过在类路径上添加ttf字体文件并调用addFont来添加自定义字体：

            renderer.getFontResolver().addFont("/fonts/Montserrat-Regular.ttf", BaseFont.IDENTITY_H, true);
            renderer.getFontResolver().addFont("/fonts/Montserrat-Italic.ttf", BaseFont.IDENTITY_H, true);
            renderer.getFontResolver().addFont("/fonts/Montserrat-Bold.ttf", BaseFont.IDENTITY_H, true);
            renderer.getFontResolver().addFont("/fonts/Montserrat-BoldItalic.ttf", BaseFont.IDENTITY_H, true);

并在CSS中指定字体：

html {
  font-family: 'Montserrat', sans-serif;
  font-size: 14px;
}

Answer 1

问题是由于在响应的输出流中生成PDF后设置了响应标头。

我的控制器是这样的：

    @GetMapping("/{id}/download-pdf")
    @Secured(Roles.ADMIN)
    public void downloadPDFResource(@PathVariable("id") EntityId entityId,
                                    HttpServletRequest request, HttpServletResponse response,
                                    Locale locale) throws IOException {
        byte[] pdf = pdfService.generatePdf("details-pdf", context);
        response.getOutputStream().write(pdf);
        response.setContentType("application/pdf");
        response.addHeader("Content-Disposition",
                           "attachment; filename=" + "document.pdf");

        response.getOutputStream().flush();
    }

修复是将内容类型和标题的设置移动到方法的顶部：

    @GetMapping("/{id}/download-pdf")
    @Secured(Roles.ADMIN)
    public void downloadPDFResource(@PathVariable("id") EntityId entityId,
                                    HttpServletRequest request, HttpServletResponse response,
                                    Locale locale) throws IOException {
        response.setContentType("application/pdf");
        response.addHeader("Content-Disposition",
                           "attachment; filename=" + "document.pdf");

        byte[] pdf = pdfService.generatePdf("details-pdf", context);
        response.getOutputStream().write(pdf);

        response.getOutputStream().flush();
    }