how to display and download a file

@RequestMapping(path="/downloadFile",method=RequestMethod.GET)
@Consumes(MediaType.APPLICATION_JSON_VALUE)
public  ResponseEntity<InputStreamReader> downloadDocument(String acquistionId,String fileType,Integer expressVfId)
        throws IOException {
    File file2Upload = new File("C://Users//admin//Desktop//bkp//1.rtf");
    HttpHeaders headers = new HttpHeaders();
    headers.add("Cache-Control", "no-cache, no-store, must-revalidate");
    headers.add("Pragma", "no-cache");
    headers.add("Expires", "0");
    InputStreamReader i = new InputStreamReader(new FileInputStream(file2Upload));
    System.out.println("The length of the file is : "+file2Upload.length());

    return ResponseEntity.ok().headers(headers).contentLength(file2Upload.length())
            .contentType(MediaType.parseMediaType("application/octet-stream"))
            .body(i);
    }

ihave been tried this.but this is not my solution…

if the number of lines is exceeded 1000 it automatically download,else it display the corresponding page in spring boot,i want the code for this..