微信全局获取并缓存Accesstoken的值

由于本项目中使用自定义菜单接口、获取用户信息接口、用户分组接口、消息发送接口等，都需要传入一个相同的参数access_token，其有效期 是7200秒（两小时），在有效期内可以使用，一旦access_token过期，需要重新通过调用微信接口获取。目前微信接口上面获取 access_token每日限额为2000次，如果Oauth2.0授权、发送主动消息、获取用户信息、群发信息之前都去获取，必然会达到该接口的频率 限制，因此需要把获取到的access_token存储起来，然后设置有效期，在有效期过期后再去获取，以保证access_token实时的有效性。详 细代码如下：

a.       新建xml文件，命名为XMLToken.xml。

<?xml version="1.0" encoding="utf-8"?>

<xml>

  <AccessToken></AccessToken>

  <AccessExpires></AccessExpires>

</xml>

b.       AccessToken实体结构如下：

    public class AccessToken

    {

        public stringaccess_token { get; set;}

        public int expires_in{ get; set; }

    }

c.       获取AccessToken（）和getJson()方法如下：

        public AccessTokenGetAccessToken(string CorpId, string Secret)

        {

           string str_accessToken ="https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid="+ CorpId +"&corpsecret=" +Secret;

           string accessToken = GetJson(str_accessToken);

           AccessToken getAccessToken =js.Deserialize<AccessToken>(accessToken);

           return getAccessToken;

        }

 

      public stringGetJson(string url)

        {

           WebClient wc = newWebClient();

           wc.Credentials = CredentialCache.DefaultCredentials;

           wc.Encoding = Encoding.UTF8;

           string returnText = wc.DownloadString(url);

           if (returnText.Contains("errcode"))

           {

               //可能出错

            }

           return returnText;

        }

 

d.       校验AccessToken是否过期方法 GetExistAccessToken()如下：

public stringGetExistAccessToken()

        {

           string filepath = System.Web.HttpContext.Current.Server.MapPath("XMLToken.xml");

           StreamReader str = newStreamReader(filepath ,System.Text.Encoding.UTF8);

           XmlDocument xml = newXmlDocument();

           xml.Load(str);

           str.Close();

           str.Dispose();

           string token = xml.SelectSingleNode("xml").SelectSingleNode("AccessToken").InnerText;

           string time = xml.SelectSingleNode("xml").SelectSingleNode("AccessExpires").InnerText;

           if (string.IsNullOrEmpty(token)||string.IsNullOrEmpty(time))

           {

               AccessToken getAccessToken =GetAccessToken(str_CorpId, str_Secret);

               xml.SelectSingleNode("xml").SelectSingleNode("AccessToken").InnerText =getAccessToken.access_token;

               DateTime _accessExpires =DateTime.Now.AddSeconds(getAccessToken.expires_in);

               xml.SelectSingleNode("xml").SelectSingleNode("AccessExpires").InnerText =_accessExpires.ToString();

               xml.Save(filepath);

               token = getAccessToken.access_token;

           }

           else if (!string.IsNullOrEmpty(token) || !string.IsNullOrEmpty(time))

           {

               DateTime AccessExpires =Convert.ToDateTime(time);

               if (DateTime.Now> AccessExpires)

               {

                   AccessToken getAccessToken =GetAccessToken(str_CorpId, str_Secret);

                   xml.SelectSingleNode("xml").SelectSingleNode("AccessToken").InnerText =getAccessToken.access_token;

                   DateTime _accessExpires =DateTime.Now.AddSeconds(getAccessToken.expires_in);

                   xml.SelectSingleNode("xml").SelectSingleNode("AccessExpires").InnerText =_accessExpires.ToString();

                   xml.Save(filepath);

                   token = getAccessToken.access_token;

               }

           }

           return token;

        }