netty操作cookie和session遇到问题：报错

刚接触netty，不是很熟，希望高手指点

现在能够正确读取客户端的cookie，代码如下

HttpRequest request = (HttpRequest) e.getMessage();

String value = request.getHeader("Cookie");
System.out.println(value);

但是不能将cookie写入程序，如下代码可能有问题但又不知出在哪了

HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
CookieEncoder encoder = new CookieEncoder(true);
encoder.addCookie("name","shenzhen");
String encodedCookie = encoder.encode();
response.setHeader(HttpHeaders.Names.COOKIE, encodedCookie);
response.setHeader("Content-Type", "text/html; charset=UTF-8");
response.setHeader("Content-Length", response.getContent()
  .writerIndex());

channel.write(response);
channel.disconnect();
channel.close();

知道的，请指点呀，都弄了一天了