download a file using Angular JS and a Spring-based RESTful web service

I'm using Spring boot and Angular JS . I have a Spring REST Controller that I use to download a File. when I call it using http://localhost:8080/download it works and the file is downloaded. Now I have a button ,when I click on it , I the file will be downloaded . so I wrote a function in my angular js controller to get the url of my spring web service but when I tested it nothing happened . what should I do to fix this ? Is there a better way to download files using Spring and Angular ?

 /**
 * Size of a byte buffer to read/write file
 */
private static final int BUFFER_SIZE = 4096;
private String filePath = "C:\\Users\\marwa\\Desktop\\marwa\\gg.jpg";

/**
 * Method for handling file download request from client
 */
@RequestMapping (value="/download", method=RequestMethod.GET )
public void doDownload(HttpServletRequest request,
        HttpServletResponse response) throws IOException {

    // get absolute path of the application
    ServletContext context = request.getServletContext();
    String appPath = context.getRealPath("");
    System.out.println("filepath = " + filePath);

    // construct the complete absolute path of the file

    File downloadFile = new File(filePath);
    FileInputStream inputStream = new FileInputStream(downloadFile);

    // get MIME type of the file
    String mimeType = context.getMimeType(filePath);
    if (mimeType == null) {
        // set to binary type if MIME mapping not found
        mimeType = "application/octet-stream";
    }
    System.out.println("MIME type: " + mimeType);

    // set content attributes for the response
    response.setContentType(mimeType);
    response.setContentLength((int) downloadFile.length());

    // set headers for the response
    String headerKey = "Content-Disposition";
    String headerValue = String.format("attachment; filename=\"%s\"",
            downloadFile.getName());
    response.setHeader(headerKey, headerValue);

    // get output stream of the response
    OutputStream outStream = response.getOutputStream();

    byte[] buffer = new byte[BUFFER_SIZE];
    int bytesRead = -1;

    // write bytes read from the input stream into the output stream
    while ((bytesRead = inputStream.read(buffer)) != -1) {
        outStream.write(buffer, 0, bytesRead);
    }

    inputStream.close();
    outStream.close();

}

my angular js function ( I added console.log("ok") to see if I get a result from the spring controller and it printed ok )

$scope.downloadFile = function () {                   
        $http({method: 'GET', url: '/download'}).
         success(function(result) {
                        console.log("ok");
          }).
     error(function(data, status, headers, config) {
            console.log("oops");
         });
 };

and my button

<button  class="btn btn-success" ng-click="downloadFile()">download</button>