从弹簧控制器下载文件 [英] Downloading a file from spring controllers

问题描述

我需要从网站下载PDF档案。 PDF需要在代码中生成，我认为这将是freemarker和一个PDF生成框架（如iText）的组合。任何更好的方法？

I have a requirement where I need to download a PDF from the website. The PDF needs to be generated within the code, which I thought would be a combination of freemarker and a PDF generation framework like iText. Any better way?

但是，我的主要问题是如何允许用户通过Spring控制器下载文件？

However, my main problem is how do I allow the user to download a file through a Spring Controller?

推荐答案

@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， code> response.getOutputStream（），你可以写任何东西。您可以将此输出流作为一个地方，将生成的PDF到您的生成器。此外，如果您知道要发送的文件类型，可以设置

Generally speaking, when you have response.getOutputStream(), you can write anything there. You can pass this output stream as a place to put generated PDF to your generator. Also, if you know what file type you are sending, you can set

response.setContentType("application/pdf");

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