@RequestMapping(value = "/files/{file_name}", method = RequestMethod.GET)
public void getFile(
    @PathVariable("file_name") String fileName, 
    HttpServletResponse response) {
    try {
      // get your file as InputStream
      InputStream is = ...;
      // copy it to response's OutputStream
      org.apache.commons.io.IOUtils.copy(is, response.getOutputStream());
      response.flushBuffer();
    } catch (IOException ex) {
      log.info("Error writing file to output stream. Filename was '{}'", fileName, ex);
      throw new RuntimeException("IOError writing file to output stream");
    }

}

一般来说，当你拥有时response.getOutputStream()，你可以在其中编写任何内容。你可以将此输出流作为将生成的PDF放置到生成器的地方。另外，如果你知道要发送的文件类型，则可以设置

response.setContentType("application/pdf");

通过使用Spring的ResourceHttpMessageConverter中的内置支持，我能够简化这一过程。如果可以确定mime类型，则将设置content-length和content-type

@RequestMapping(value = "/files/{file_name}", method = RequestMethod.GET)
@ResponseBody
public FileSystemResource getFile(@PathVariable("file_name") String fileName) {
    return new FileSystemResource(myService.getFileFor(fileName)); 
}