使用ArkTs的请求如何以JSON的形式传输

import { http } from '@kit.NetworkKit';

class Header {
  public contentType: string;
  constructor(contentType: string) {
    this.contentType = contentType;
  }
}
let httpRequest = http.createHttp();
let promise = httpRequest.request("EXAMPLE_URL", {
  method: http.RequestMethod.GET,
  connectTimeout: 60000,
  readTimeout: 60000,
  header: new Header('application/json')
});