我有一个后端API，它在我们调用它时基本上会下载一个模板。我在html页面上提供了href，因此，每当有人单击该href时，它就会调用后端API，并且应该下载该文件。

但是该文件未下载。

我正在使用React。如果我只是从浏览器访问后端，则文件将被下载，但是如果我从react调用，则不会。

有线索吗？

反应代码：

const config = require('config');

var aws4 = require('aws4');

const Promise = require('axios');



const requestHelper = {

  appendHeaders(request){

    request.headers = request.headers || {};

    if(request.headers["Content-Type"]){

      return

    }

    request.headers["Content-Type"] = "application/json";

  },

  externalApi(request, serverResult){

    if(!request.method){

      request.method='POST';

    }

    request.path = request.url

    this.appendHeaders(request)

   console.log('request',request)

    return Promise(request)

    .then((apiResponse) => {

      if (apiResponse.data.errors) {

        var error = apiResponse.data.errors;

        console.log('api error response: ', error);

        serverResult.status(400).json({ error })

      } else {

        console.log('api response: ', apiResponse.data);

        serverResult.status(200).json(apiResponse.data);

      }

    }).catch((error) => {

      console.log('api error response: ', error);

      serverResult.status(400).json({ error });

    });

   },



   getDownloadResponse(request, serverResult){

    debugger;

    request.path = request.url

    this.appendHeaders(request)

    console.log(request);

    return Promise(request)

    .then((apiResponse) => {

      if (apiResponse.data.errors) {

        var error = apiResponse.data.errors;

        console.log('api error response: ', error);

        serverResult.status(400).json({ error })

      } else {

        serverResult.status(200);

        console.log('api response status: '+200);

      }

    }).catch((error) => {

      console.log('api error response: ', error);

      serverResult.status(400).json({ error });

    });

   }

};



module.exports = requestHelper;

后端API代码：

@RequestMapping(value = GlobalConstants.DOWNLOAD_FILE, method = RequestMethod.GET)
public void downloadTemplate(HttpServletRequest hRequest, HttpServletResponse response) throws Exception {

    InputStream in = null;
    OutputStream out = null;
    try {
        if (!StringUtils.isEmpty(sampleFile)) {
            File file = new File(sampleFile);
            in = finderService.downloadFile(sampleFile);
            if (in != null) {
                MimetypesFileTypeMap mimetypesFileTypeMap = new MimetypesFileTypeMap();
                response.setContentType(mimetypesFileTypeMap.getContentType(file));
                String headerKey = "Content-Disposition";
                String headerValue = String.format("attachment; filename=\"%s\"", file.getName());
                response.setHeader(headerKey, headerValue);

                out = response.getOutputStream();
                byte[] buffer = new byte[4096];
                int length;
                while ((length = in.read(buffer)) > 0) {
                    out.write(buffer, 0, length);
                }
            }
        } else {
        response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        }
        logger.error("Internal Server error"); //Add logs for server error here also

    } catch (Throwable th) {
        response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        logger.error(th);
        return;
    } finally {
        if (in != null) {
            in.close();
        }
        if (out != null) {
            out.flush();
        }
    }
}