将PNG图片从后端保存到前端到本地Angular Project文件夹

Question

I want to save a PNG image received from Backend (Java Project) to a folder inside my Angular Project. So far I can only save the image under Downloads/ folder of the PC and you can see how the file is downloaded. What I want is to silently download the image in my project (when I check the folder to see the new image stored).

Backend:

    @GET
    @Produces(MediaType.TEXT_PLAIN)
    @Path("getImage")
    public Response getImage() {
        File dir = new File(Utilities.IMAGE_DIRECTORY);
        File[] directoryListing = dir.listFiles();
        String encodedImages = null;

        // Get the first image stored in Backend project folder
        try {
            if (directoryListing != null) {
                // Encode the image in Base64 and save it in a string
                encodedImages = Base64
                                 .getEncoder()
                                 .withoutPadding()
                                 .encodeToString(
                        Files.readAllBytes(directoryListing[0].toPath()));
            }
        } catch (IOException e) {
            e.printStackTrace();
            ...
        }

        // Send the base64 string to Frontend
        return Response
                .status(Response.Status.OK)
                .entity(encodedImages)
                .build();
    }

Frontend:

  /* Extract Image */
  getImage() {
    this
      .http
      .get(this.baseUrl + "getImage", { responseType: 
       'text' })
      .subscribe((res) => {
        console.log("I received the image: \n" + res);

        // Decode from base64 to PNG
        var decodedImage = atob(res);

        var blob = new Blob([decodedImage], { type: 'image/png' });

        //this method saves the image in Downloads/ and it is not silent
        saveAs(blob, 'imageFileName.png');
    });
  }

Answer 1

Since your user will not need the image it self why to download it? You don't need to download the image just for using it. Only if your user need to download the image you could go with and "Save File" system.