HTTPClient實現免登陸請求（帶cookie請求）

背景：

使用httpClient請求某登錄型網站，模擬一個操作，一般步驟一個httpclient模式登錄-》httpClient模擬操作；

此時發現，每次操作都需要進行一次登錄，極其浪費時間，是否可以通過某一方式進行一次登錄多次操作，這里提供一種方式，帶cookie登錄。

登錄獲取cookie：

    public String loginModel(String username, String password) {
        String JSESSIONID = null;
        HttpPost httppost = new HttpPost(url);//httppost
        try {
            List<NameValuePair> para = new ArrayList<NameValuePair>();
            para.add(new BasicNameValuePair("password", password));
            para.add(new BasicNameValuePair("username", username));//構造表單
            httppost.setHeader(
                    "User-Agent",
                    "Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.118 Safari/537.36");
            httppost.setEntity(new UrlEncodedFormEntity(para, "utf-8"));//設置請求體
            BasicCookieStore cookieStore = new BasicCookieStore();//建立一個CookieStore
            CloseableHttpClient httpClient = HttpClients.custom().setDefaultCookieStore(cookieStore).build();//建立帶cookie的httpClient
            int statuts_codes = httpClient.execute(httppost).getStatusLine().getStatusCode();//發送請求，發送成功后cookie將存在於cookieStore中
            if (statuts_codes == HttpStatus.SC_OK) {//請求成功
                List<Cookie> cookies = cookieStore.getCookies();//遍歷獲取需要的值
                for (int i = 0; i < cookies.size(); i++) {//獲取JSESSIONID
                    if (cookies.get(i).getName().equals("id")) {
                        JSESSIONID = cookies.get(i).getValue();
                    }
                }
                cookieMap.put("JSESSIONID", JSESSIONID);
               
            } else {//請求失敗
               
            }
        } catch (UnsupportedEncodingException ex) {
            
        } catch (IOException ex) {
            
        } finally {
            httppost.releaseConnection();//釋放資源
        }
        return cookieMap.get("JSESSIONID");
    }

創建帶有cookie的HttpClient

 public CloseableHttpClient getHttpClients(String username, String password) {
        BasicCookieStore cookieStore = new BasicCookieStore();
        HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();
        String JSESSIONID = loginModel(username, password);
        BasicClientCookie cookie = new BasicClientCookie("JSESSIONID", JSESSIONID);
        cookie.setVersion(0);
        String domain = Constant.HOOK_URL.substring(0, Constant.HOOK_URL.indexOf(":"));
        if (Constant.HOOK_URL.startsWith("http://")) {
            domain = Constant.HOOK_URL.substring(Constant.HOOK_URL.lastIndexOf("/") + 1, Constant.HOOK_URL.lastIndexOf(":"));
        }
        cookie.setDomain(domain);
        cookie.setPath(Constant.HOOK_FW);
        cookieStore.addCookie(cookie);
        //帶有cookie的httpclient
        return httpClientBuilder.setDefaultCookieStore(cookieStore).build();
    }

使用：

public void useCookieHttpClient() {

        CloseableHttpClient httpClient = getHttpClients(user, pass);
        HttpPost httppost = new HttpPost(url2);
        List<NameValuePair> para = new ArrayList<>();//表單
        para.add("鍵", "值");
        httppost.setEntity(new UrlEncodedFormEntity(para, "utf-8"));
        httppost.setEntity(new UrlEncodedFormEntity(para, "utf-8"));
        CloseableHttpResponse res = httpClient.execute(httppost);
        int statuts_codes = res.getStatusLine().getStatusCode();
        if (statuts_codes == HttpStatus.SC_OK) {//請求成功
            String result = EntityUtils.toString(res.getEntity(), "utf-8");//返回值
        }

    }