http请求网页编码乱码

let url = "https://zhidao.baidu.com/";
let r = http.get(url);
let bytes = r.body.bytes();
let bais = new java.io.ByteArrayInputStream(bytes);
let isr = new java.io.InputStreamReader(bais, "gbk");
let sb = new java.lang.StringBuffer();
let br = new java.io.BufferedReader(isr);
let str;
while ((str = br.readLine()) != null) {
  sb.append(str);
}
bais.close();
isr.close();
br.close();
log(sb);