C#微信开发之旅(三)：AccessToken获取及全局管理

 1 /// <summary>
 2     /// AccessToken类，公众号通过此token 获取相关信息 （单例类）
 3     /// </summary>
 4     public sealed class AccessToken
 5     {
 6         private static AccessToken _Token = new AccessToken();
 7 
 8         private static object lock_Object = new object();
 9 
10         /// <summary>
11         /// 此处 会判断是否过期，没过期返回原存储的Token
12         /// </summary>
13         public static AccessToken Instance
14         {
15             get
16             {
17                 if (_Token.Expired)
18                 {
19                     lock (lock_Object)
20                     {
21                         if (_Token.Expired)
22                         {
23                             _Token.CreateTime = DateTime.Now;
24                             _Token.CopyModel(JsonConvert.DeserializeObject<AccessToken>(WeiXinHelper.GetAccessToken()));
25                         }
26                     }
27                 }
28 
29                 return _Token;
30             }
31         }
32 
33         /// <summary>
34         /// 此处会创建新的Token返回，只有在调用接口提示AccessToken过期时 才调用这个接口。
35         /// </summary>
36         /// <returns></returns>
37         public static AccessToken CreateNewInstance()
38         {
39             lock (lock_Object)
40             {
41                 _Token.CreateTime = DateTime.Now;
42                 _Token.CopyModel(JsonConvert.DeserializeObject<AccessToken>(WeiXinHelper.GetAccessToken()));
43             }
44             return _Token;
45         }
46 
47         private AccessToken()
48         {
49             CreateTime = DateTime.Now;
50             _expiresIn = -1;
51         }
52 
53         private string _accessToken;
54         private int _expiresIn;
55         public DateTime CreateTime;
56         public string Access_Token
57         {
58             get { return _accessToken; }
59             set { _accessToken = value; }
60         }
61 
62         /// <summary>
63         /// 有效时间，秒
64         /// </summary>
65         public int Expires_In
66         {
67             get { return _expiresIn; }
68             set { _expiresIn = value; }
69         }
70 
71         public bool Expired
72         {
73             get
74             {
75                 DateTime expiredTime = CreateTime.AddSeconds(_expiresIn);
76 
77                 if (DateTime.Now > expiredTime)
78                     return true;
79 
80                 return false;
81             }
82         }
83 
84         public void CopyModel(AccessToken token)
85         {
86             //token 为空，将 过期时间 设置为 -1
87             if (token == null)
88             {
89                 this.Expires_In = -1;
90                 return;
91             }
92 
93             this.Access_Token = token.Access_Token;
94             this.Expires_In = token.Expires_In;
95 
96         }
97     }

        /// <summary>
        /// 获取Access_Token
        /// </summary>
        /// <returns></returns>
        public static string GetAccessToken()
        {
            string url = WeiXinConst.WeiXin_AccessTokenUrl;
            string result = HttpClientHelper.GetResponse(url);
            return result;
        }