ASP.NET获取在线接口数据HttpGet

哈喽，筒子们。又是令人开心的周六

忙碌（搬砖）的一周又过去了，让我们来看一下今天要写点什么吧

首先接口API相信入行多年的选手都不陌生了，你调用我，我调用你，拿来拿去是很熟悉的都。

那么今天来写点关于调用接口获取Json数据的内容吧【HTTPGET】

首先调用对方地址这个是肯定有的了，那么怎么安全的获取到数据呢。

直接上方法。

   private string GetDataJsonBy(string url)
        {
            string result = string.Empty;
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
            HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
            Stream stream = resp.GetResponseStream();
            try
            {
                //获取内容
                using (StreamReader reader = new StreamReader(stream))
                {
                    result = reader.ReadToEnd();
                }
            }
            finally
            {
                stream.Close();
            }
            return result;
        }

HttpWebRequest和HttpWebResponse类是用于发送和接收HTTP数据的最好选择。它们支持一系列有用的属性。这两个类位 于System.Net命名空间，默认情况下这个类对于控制台程序来说是可访问的。请注意，HttpWebRequest对象不是利用new关键字通过构 造函数来创建的，而是利用工厂机制（factory mechanism）通过Create()方法来创建的。另外，你可能预计需要显式地调用一个“Send”方法，实际上不需要。接下来调用 HttpWebRequest.GetResponse()方法返回的是一个HttpWebResponse对象。你可以把HTTP响应的数据流 （stream）绑定到一个StreamReader对象，然后就可以通过ReadToEnd()方法把整个HTTP响应作为一个字符串取回。也可以通过 StreamReader.ReadLine()方法逐行取回HTTP响应的内容。

上面这段说的应该是比较清楚了，那这个Create方法里面具体是怎么做的呢？一起来八一八源代码

        // Create - Create a WebRequest.
        //
        // An overloaded utility version of the real Create that takes a
        // string instead of an Uri object.
        //
        // Input:
        //     RequestString       - Uri string to create.
        //
        // Returns:
        //     Newly created WebRequest.
        [Obsolete(Obsoletions.WebRequestMessage, DiagnosticId = Obsoletions.WebRequestDiagId, UrlFormat = Obsoletions.SharedUrlFormat)]
        public static WebRequest Create(string requestUriString)
        {
            if (requestUriString == null)
            {
                throw new ArgumentNullException(nameof(requestUriString));
            }
 
            return Create(new Uri(requestUriString), false);
        }
 

我们看到了，C#的源码做的还是很好的，在最新版里面这个方法已经是被Obsolete了的。

不过不影响我们看它的实现，看看它内部调用的Create重载是怎么写的

        // Create a WebRequest.
        //
        // This is the main creation routine. We take a Uri object, look
        // up the Uri in the prefix match table, and invoke the appropriate
        // handler to create the object. We also have a parameter that
        // tells us whether or not to use the whole Uri or just the
        // scheme portion of it.
        //
        // Input:
        //     requestUri - Uri object for request.
        //     useUriBase - True if we're only to look at the scheme portion of the Uri.
        //
        // Returns:
        //     Newly created WebRequest.
        private static WebRequest Create(Uri requestUri, bool useUriBase)
        {
            string LookupUri;
            WebRequestPrefixElement? Current = null;
            bool Found = false;
 
            if (!useUriBase)
            {
                LookupUri = requestUri.AbsoluteUri;
            }
            else
            {
                // schemes are registered as <schemeName>":", so add the separator
                // to the string returned from the Uri object
                LookupUri = requestUri.Scheme + ':';
            }
 
            int LookupLength = LookupUri.Length;
 
            // Copy the prefix list so that if it is updated it will
            // not affect us on this thread.
 
            List<WebRequestPrefixElement> prefixList = PrefixList;
 
            // Look for the longest matching prefix.
 
            // Walk down the list of prefixes. The prefixes are kept longest
            // first. When we find a prefix that is shorter or the same size
            // as this Uri, we'll do a compare to see if they match. If they
            // do we'll break out of the loop and call the creator.
 
            for (int i = 0; i < prefixList.Count; i++)
            {
                Current = prefixList[i];
 
                // See if this prefix is short enough.
 
                if (LookupLength >= Current.Prefix.Length)
                {
                    // It is. See if these match.
                    if (string.Compare(Current.Prefix,
                                       0,
                                       LookupUri,
                                       0,
                                       Current.Prefix.Length,
                                       StringComparison.OrdinalIgnoreCase) == 0)
                    {
                        // These match. Remember that we found it and break
                        // out.
                        Found = true;
                        break;
                    }
                }
            }
 
            if (Found)
            {
                // We found a match, so just call the creator and return what it does.
                WebRequest webRequest = Current!.Creator.Create(requestUri);
                return webRequest;
            }
 
            // Otherwise no match, throw an exception.
            throw new NotSupportedException(SR.net_unknown_prefix);
        }

瞧瞧人家这个代码写的，这命名，这质量，这注释。

再瞧瞧我们的项目，诶~（露头会被打死）

源码已贴

后面的代码你们自己扒拉吧，不贴了。【我才不会说我看不懂了】

    [HttpGet]
        public IHttpActionResult GetPersonnel()
        {
            DateTime startDay = new DateTime(2019, 5, 1);
            DateTime endDay = new DateTime(2019, 5, 2);
            TimeSpan leftTime =  new DateTime(2020, 12, 1)- startDay;
            int leftDay = Convert.ToInt32(leftTime.TotalDays);
            #region Info

            for (int i = 0; i < leftDay; i++)
            {
                string uri = "http://main.demo.com/api/personnel/getdemo?beginDate="+startDay.AddDays(i)+"&endDate=" + endDay.AddDays(i);

                string resultJson = GetDataJsonBy(uri);
                IList<Demo> data = JsonConvert.DeserializeObject<List<Demo>>(resultJson);

                foreach (var item in data)
                {
                    Demo entity = Demo.GetList(new { DataId = item.id }.ToJson()).FirstOrDefault();
                   
                    if (entity == null)
                    {//save new。
                        demo.SaveForm("", new nhw_EmployeesEntity{

　　　　　　　　　　　　　　entityData.Mail = item.mailAddress,
                        entityData.Photo = item.picture
　　　　　　　　　　　　　　});
                        continue;
                    }
                    
                    entity.Mail = item.mailAddress;
                    entity.Photo = item.picture;
                    demo.SaveForm(entity.ID.ToString(), entity);
                }


            }
            #endregion

            return Json("");
        }

 抛砖引玉，我这里只是贴了一个简单的方法去获取到数据，并且进行了数据库的增改操作。

欢迎大家指正