Question

我有这个网络服务从电子邮件下载文件（我提供下载URL）：

@Override
@PreAuthorize("hasRole('ROLE_ADMIN')")
@RequestMapping(value = { "download"}, method = RequestMethod.GET)
public void downloadFile(HttpServletResponse response, @RequestParam(value="filePath", required = true) String filePath) {
    try{
        File file = new File(filePath);
        if (file.isFile()){
            try(InputStream is = new FileInputStream(file.getAbsolutePath())){
                setResponse(response, is, file, "attachment; filename=");
            }catch (Exception e1){
                ErrorResponse errorResponse= ErrorResponseBuilder.buildErrorResponse(e1);
                LOG.error("Threw exception in FleetAndCarControllerImpl::downloadStatisticalFile :" + errorResponse.getStacktrace());
            }
        }else{
            //TODO write that file is not present
        }
    }catch (Exception e) {
        ErrorResponse errorResponse= ErrorResponseBuilder.buildErrorResponse(e);
        LOG.error("Threw exception in FleetAndCarControllerImpl::downloadStatisticalFile :" + errorResponse.getStacktrace());
    }
}

和setResponse方法：

private void setResponse(HttpServletResponse response, InputStream is, File file, String useOfFile) throws Exception{
        response.setHeader("Expires", "0");
        response.setHeader("Cache-Control","must-revalidate, post-check=0, pre-check=0");
        response.setContentType(Files.probeContentType(file.toPath()));
        response.setHeader("Content-Description"," File Transfer");
        response.setHeader("Content-Disposition", useOfFile + file.getName());
        response.setHeader("Content-Transfer-Encoding"," binary");
        long size = Utils.stream(is, response.getOutputStream());
        response.addHeader("Content-Length", Long.toString(size));
        response.flushBuffer();
    }

当文件存在时，它可以正常工作，现在我想写一条消息，如果文件不存在，因为现在用户查看空白页面并且它不知道发生了什么。你能帮助我吗？

Answer 1

您可以执行以下操作：

response.sendError(HttpServletResponse.SC_NOT_FOUND, "File was not found");

或者更好地将重定向发送到带有错误消息的页面/解释下一步该做什么。

将消息设置为从Web服务返回的文件下载空白页

1 个答案: