How to download a file in Spring RestController?

@ResponseStatus(HttpStatus.OK)
@RequestMapping(value = {"/download/excel-report"},
                method = RequestMethod.GET)
public HttpEntity<byte[]> downloadExcelReport() {

    /** assume that below line gives you file content in byte array **/
    byte[] excelContent = getReportContent();
    // prepare response
    HttpHeaders header = new HttpHeaders();
    header.setContentType(new MediaType("application", "vnd.openxmlformats-officedocument.spreadsheetml.sheet"));
    header.set(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=my_file.xls");
    header.setContentLength(excelContent.length);

    return new HttpEntity<byte[]>(excelContent, header);
}