title: how to access redirectAttributes.addFalshAttributed value in hbs(handlebars) file
body: <pre><code>@PostMapping("/upload") // //new annotation since 4.3
  public String singleFileUpload(@RequestParam("file") MultipartFile file,
                                 RedirectAttributes redirectAttributes) {
      if (file.isEmpty()) {
          redirectAttributes.addFlashAttribute("message", "Please select a file to upload");
          return "redirect:uploadStatus";
      }
      try {
          // Get the file and save it somewhere
          byte[] bytes = file.getBytes();
          Path path = Paths.get(UPLOADED_FOLDER + file.getOriginalFilename());
          Files.write(path, bytes);
  
          redirectAttributes.addFlashAttribute("message",
                  "You successfully uploaded '" + file.getOriginalFilename() + "'");
  
      } catch (IOException e) {
          e.printStackTrace();
      }
  
      return "redirect:/uploadStatus";
  }
  </code></pre>
  
  <p>how to access message value of above code. </p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html lang="en" xmlns:th="http://www.thymeleaf.org"&gt;
  &lt;body&gt;
  
  &lt;h1&gt;Spring Boot - Upload Status&lt;/h1&gt;
  
  
  &lt;h2&gt;{{message}}&lt;/h2&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>The above code can't access message value.  how to access in handlebars file.
  I want to show string of message variable.</p>