final OkHttpClient client = new OkHttpClient().newBuilder()
        .followRedirects(false) //禁制OkHttp的重定向操作，我們自己處理重定向
        .followSslRedirects(false)
        .cookieJar(new LocalCookieJar())  //為OkHttp設置自動攜帶Cookie的功能
        .build();

//CookieJar是用于保存Cookie的
class LocalCookieJar implements CookieJar{
  List<Cookie> cookies;
  @Override
  public List<Cookie> loadForRequest(HttpUrl arg0) {
     if (cookies != null)
        return cookies;
      return new ArrayList<Cookie>();
  }

  @Override
  public void saveFromResponse(HttpUrl arg0, List<Cookie> cookies) {
    this.cookies = cookies;
  }
  
}

/**
  * Populates request with defaults and cookies.
  *
  * <p>This client doesn't specify a default {@code Accept} header because it doesn't know what
  * content types the application is interested in.
  */
 private Request networkRequest(Request request) throws IOException {
  Request.Builder result = request.newBuilder();

  //如果CookieJar的Cookie不為空，則設置Cookie字段
  List<Cookie> cookies = client.cookieJar().loadForRequest(request.url());
  if (!cookies.isEmpty()) {
   result.header("Cookie", cookieHeader(cookies));
  }

  return result.build();
 }

    final OkHttpClient client = new OkHttpClient().newBuilder()
        .followRedirects(false)
        .followSslRedirects(false)
        .cookieJar(new LocalCookieJar())
        .build();
    //構造一個POST請求
    RequestBody body = new FormBody.Builder().add("UserStyle", "student")
        .add("user", "xxx").add("password", "xxx").build();
        
    Request request = new Request.Builder().url("http://222.195.8.201/pass.asp").post(body).build();
    
    client.newCall(request).enqueue(new Callback() {
      
      @Override
      public void onResponse(Call call, Response response) throws IOException {
        /**
         * 如果不用CookieJar,那么就要自己去解析返回的Set-Cookie字段,解析之后通過addHeader("Cookie", cookie)
         * 添加Cookie請求頭
         */
//       List<String> cookies = response.headers("Set-Cookie");
//       String cookie = "";
//       for(int i=cookies.size()-1; i>=0; i--){
//         cookie = cookie+ cookies.get(i).replace("path=/", "") + " ";
//       }
        
        //做GET請求
        Request redirectRequest = new Request.Builder().url("http://222.195.8.201/student/asp/Select_Success.asp")
//          .addHeader("Cookie", cookie)
           .build();
        //拿到登陸后操作的某個網(wǎng)頁的內(nèi)容
        Response response2 = client.newCall(redirectRequest).execute();
        String result = response2.body().string();
        System.out.println(result);
      }
      
      @Override
      public void onFailure(Call arg0, IOException arg1) {
        
      }
    });