asp.net mvc json数据缓存

一些虚拟主机资源给的少, 如果直接用框架缓存, 估计内存就爆了吧, 如果不用缓存, 虚拟主机自带的数据库也是限制资源的, 访问多了就直接给timeout了,

用json文件形式缓存查询出来的数据, 虽然占用一些空间, 使用一些IO, 也是比查询数据库快的, 至少不会timeout了, 不过会占用一些空间, 可是现在虚拟主机空间都不小了, 不差这一点了哈哈,

key直接作为文件名了,扩展名乱写的(*.cache)

超时时间比较用的是DateTime.Ticks, 单位是微妙, 看下面的换算吧, 在AppSetting中增加一个cache_time节点, 单位是秒

<appSettings>
    <!-- 缓存时间, 单位(秒) -->
    <add key="cache_time" value="120" />
</appSettings>

 public class JCache
 {
     public static string DirPath { get; set; }
     private static string SplitChar = "!/~/#!";
     /// <summary>
     /// 缓存时间(秒)
     /// </summary>
     private static long CacheTime
     {
         get
         {
             return Convert.ToInt64(ConfigurationManager.AppSettings["cache_time"]) * ;
         }
     }
     public static T Get<T>(string key)
         where T : class, new()
     {
         var filename = Path.Combine(DirPath, key + ".cache");
         if(!Directory.Exists(DirPath))
         {
             Directory.CreateDirectory(DirPath);
         }
         if (!File.Exists(filename))
             return null;
         var fileContent = string.Empty;// File.ReadAllText(filename, System.Text.Encoding.UTF8);
         using (var fs = new FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
         {
             fileContent = new StreamReader(fs, System.Text.Encoding.UTF8).ReadToEnd();
         }
         if (string.IsNullOrEmpty(fileContent))
             return null;
         if (!fileContent.Contains(SplitChar))
             return null;
         var arr = fileContent.Split(new string[] { SplitChar }, StringSplitOptions.RemoveEmptyEntries);
         try
         {
             var d = Convert.ToInt64(arr[]);
             if (DateTime.Now.Ticks - d > CacheTime)
                 return null;

             var res = JsonConvert.DeserializeObject<T>(arr[]);
             return res;
         }
         catch (Exception ex)
         {
             return null;
         }
     }

     public static void Set(string key, object obj)
     {
         if (!Directory.Exists(DirPath))
         {
             Directory.CreateDirectory(DirPath);
         }
         var filename = Path.Combine(DirPath, key + ".cache");
         var d = DateTime.Now.Ticks.ToString();
         if (obj == null)
             return;
         var json = JsonConvert.SerializeObject(obj);
         var fileContent = string.Concat(d, SplitChar, json);
         try
         {
             using (var fs = new FileStream(filename, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite))
             {
                 new StreamWriter(fs, System.Text.Encoding.UTF8).Write(fileContent);
             }
             //File.WriteAllText(filename, fileContent);
         }
         catch (Exception ex)
         {
             var xx = ;
         }
     }
 }

使用方法

var cahceKey = "xxxkey";
var cache = JCache.Get<T>(cacheKey);

var model = new T();
if(cache == null){
     JCache.Set<T>(cacheKey, 查询出来的数据);
}else{
    model = cache;
}