常见.NET功能代码汇总 （2）

常见.NET功能代码汇总

23，获取和设置分级缓存

获取缓存：首先从本地缓存获取，如果没有，再去读取分布式缓存
写缓存：同时写本地缓存和分布式缓存

  private static T GetGradeCache<T>(string key) where T:struct 
        {
            MemoryCacheManager localCache = MemoryCacheManager.Instance;
            if (!localCache.IsSet(key))
            {
                //本地不存在此缓存
               T  remoteValue = MemCacheManager.Instance.Get<T>(key);
               if (!ValueType.Equals(remoteValue, default(T)))
               { 
                    //如果远程有
                   localCache.Set(key, remoteValue, 1); 
               }
               else
               {
                   localCache.SetFromSeconds(key, default(T), 10); 
               }
               return remoteValue;
            }
            T value = localCache.Get<T>(key);
            return value;
        }

        private static void SetGradeCache<T>(string key,T Value,int time) where T : struct 
        {
            MemoryCacheManager localCache = MemoryCacheManager.Instance;
            localCache.Remove(key);
            localCache.Set(key, Value, time);
            MemCacheManager.Instance.Remove(key);
            MemCacheManager.Instance.Set(key, Value, time); 
        }

24，求相对目录的绝对路径

有时候，我们需要求相对于当前根目录的相对目录，比如将日志文件存储在站点目录之外，我们可以使用 ../logs/ 的方式：

 string vfileName = string.Format("../logs/{0}_{1}_{2}.log", logFileName, System.Environment.MachineName, DateTime.Now.ToString("yyyyMMdd"));
            string rootPath = HttpContext.Current.Server.MapPath("/");
            string targetPath = System.IO.Path.Combine(rootPath, vfileName);
            string fileName = System.IO.Path.GetFullPath(targetPath);
            string fileDir = System.IO.Path.GetDirectoryName(fileName);
            if (!System.IO.Directory.Exists(fileDir))
                System.IO.Directory.CreateDirectory(fileDir);

这个代码会在站点目录之外的日志目录，建立一个 代机器名称的按照日期区分的日志文件。

25，多次尝试写日志文件方法

日志文件可能会并发的写入，此时可能会提示“文件被另外一个进程占用”，因此可以多次尝试写入。下面的方法会递归的进行文件写入尝试，如果尝试次数用完才会最终报错。

  /// <summary>
        /// 保存日志文件
        /// </summary>
        /// <param name="logFileName">不带扩展名文件名</param>
        /// <param name="logText">日志内容</param>
        /// <param name="tryCount">如果出错的尝试次数，建议不大于100，如果是0则不尝试</param>
        public static void SaveLog(string logFileName, string logText, int tryCount)
        {
            string vfileName = string.Format("..\\logs\\{0}_{1}_{2}.log", logFileName, System.Environment.MachineName, DateTime.Now.ToString("yyyyMMdd"));
            string rootPath = System.AppDomain.CurrentDomain.BaseDirectory;
            string targetPath = System.IO.Path.Combine(rootPath, vfileName);
            string fileName = System.IO.Path.GetFullPath(targetPath);
            string fileDir = System.IO.Path.GetDirectoryName(fileName);
            if (!System.IO.Directory.Exists(fileDir))
                System.IO.Directory.CreateDirectory(fileDir);
            
            try
            {
                System.IO.File.AppendAllText(fileName, logText);
                tryCount = 0;
            }
            catch (Exception ex)
            {
                if (tryCount > 0)
                {
                    System.Threading.Thread.Sleep(1000);
                    logText = logText + "\r\nSaveLog,try again times =" + tryCount + " ,Error:" + ex.Message;
                    tryCount--;
                    SaveLog(logFileName, logText, tryCount);
                }
                else
                {
                    throw new Exception("Save log file Error,try count more times!");
                }
            }
        }

 26，ASP.NET获取客户端的IP地址

      string GetRemoteIP()
        {
            string result = HttpContext.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
            if (null == result || result == String.Empty)
            {
                result = HttpContext.Request.ServerVariables["REMOTE_ADDR"];
            }


            if (null == result || result == String.Empty)
            {
                result = HttpContext.Request.UserHostAddress;
            }
            return result;

27，ASP.NET MVC 在Action里面获取请求的URL

可以分为3种方式，
1）ASP.NET MVC 在控制器的默认Action里面获取请求其它Action的路径
比如在默认的 Index Action里面获取路径，如下：

string sso_url= "http://" + Request.Url.Authority + Request.Url.AbsolutePath + "/SSO?id=" + userid;

 2)在其它Action里面获取当前控制器的路径 

string ctrName = RouteData.Values["controller"].ToString();
 string redirectUrl = "http://" + Request.Url.Authority + "/" + ctrName + "/SSO?id=" + userid;

 3）直接获取当前Action请求的路径

string url=Request.Url.ToString();

 

28，ASP.NET MVC Action返回可以在浏览器直接查看的纯文本信息

需要指定Context的contentType 为“text/plain”，代码如下：

 public ActionResult SendMessage()
 {
   string txt="你好！";
   return Content(text, "text/plain", System.Text.Encoding.UTF8);
  }

 29，使用Linq2XML读写XML

这里主要使用XDocument,XElement对象来操作XML内容，如下代码：

    public static class XDocumentExtentsion
    {
        //生成XML的申明部分
        public static string ToStringWithDeclaration(this XDocument doc, SaveOptions options = SaveOptions.DisableFormatting)
        {
            return doc.Declaration.ToString() + doc.ToString(options);
        }
    }

        public string CreateMsgResult(string loginUserId,string corpid, string msg,string ts)
        {
            var xDoc = new XDocument(
                new XDeclaration("1.0", "UTF-8", null),  
                new XElement("result",
                    new XElement("corpid", corpid),
                    new XElement("userid", loginUserId),
                    new XElement("ts", ts),
                    new XElement("sendmsg", msg)
                ));
            return xDoc.ToStringWithDeclaration();
        }

        public ResponseMessage ParseXMLString(string xml)
        {
            var xDoc = XDocument.Parse(xml);
            if (xDoc == null) return null;
            var root = xDoc.Element("result");
            if(root==null)
                throw new Exception ("not found the 'result' root node,input XML\r\n"+xml);
            ResponseMessage result =
             new ResponseMessage()
             {
                 ErrorCode  = root.Element("rescode").Value,
                 ErrorMessage  = root.Element("resmsg").Value,
                 RedirectUrl  = root.Element("redirect_url") == null ? "" : root.Element("redirect_url").Value
             };
          
            return result;
        }

 30，访问Web内容的自定义代码

使用 HttpWebRequest和HttpWebResponse 对象完成Web访问，如果是.NET 4.5，建议直接使用 HttpClient对象：

        /// <summary>
        /// 获取请求结果
        /// </summary>
        /// <param name="requestUrl">请求地址</param>
        /// <param name="timeout">超时时间(秒)</param>
        /// <param name="requestXML">请求xml内容</param>
        /// <param name="isPost">是否post提交</param>
        /// <param name="encoding">编码格式 例如:utf-8</param>
        /// <param name="errorMsg">抛出的错误信息</param>
        /// <returns>返回请求结果</returns>
        public static string HttpWebRequest(string requestUrl, int timeout, string requestXML, bool isPost, string encoding, out string errorMsg, string contentType = "application/x-www-form-urlencoded")
        {
            errorMsg = string.Empty;
            string result = string.Empty;
            try
            {
                byte[] bytes = System.Text.Encoding.GetEncoding(encoding).GetBytes(requestXML);
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestUrl);
                request.Referer = requestUrl;
                request.Method = isPost ? "POST" : "GET";
                request.Timeout = timeout * 1000;
                if (isPost)
                {
                    request.ContentType = contentType;// "application/x-www-form-urlencoded";
                    request.ContentLength = bytes.Length;
                    using (Stream requestStream = request.GetRequestStream())
                    {
                        requestStream.Write(bytes, 0, bytes.Length);
                        requestStream.Close();
                    }
                }
                
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream responseStream = response.GetResponseStream();
                if (responseStream != null)
                {
                    StreamReader reader = new StreamReader(responseStream, System.Text.Encoding.GetEncoding(encoding));
                    result = reader.ReadToEnd();
                    reader.Close();
                    responseStream.Close();
                    request.Abort();
                    response.Close();
                    return result.Trim();
                }
            }
            catch (Exception ex)
            {
                errorMsg =string.Format("Error Message:{0},Request Url:{1},StackTrace:{2}", ex.Message ,requestUrl , ex.StackTrace);
            }

            return result;
        }