缓存

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Threading;
using System.Web.Caching;

namespace WebApiDemo.Common
{
    public class CacheHelper
    {
        public static object Get(string cacheKey)
        {
            return HttpRuntime.Cache[cacheKey];
        }
        public static void Add(string cacheKey, object obj, int cacheMinute)
        {
            HttpRuntime.Cache.Insert(cacheKey, obj, null, DateTime.Now.AddMinutes(cacheMinute),
                Cache.NoSlidingExpiration, CacheItemPriority.Normal, null);
        }
    }

    public class MyCache
    {
        public object GetMemberSigninDays5()
        {
            const int cacheTime = 5;
            const string cacheKey = "mushroomsir";

            //缓存标记。
            const string cacheSign = cacheKey + "_Sign";
            var sign = CacheHelper.Get(cacheSign);

            //获取缓存值
            var cacheValue = CacheHelper.Get(cacheKey);
            if (sign != null)
                return cacheValue; //未过期，直接返回。

            lock (cacheSign)
            {
                sign = CacheHelper.Get(cacheSign);
                if (sign != null)
                    return cacheValue;

                CacheHelper.Add(cacheSign, "1", cacheTime);
                ThreadPool.QueueUserWorkItem((arg) =>
                {
                    cacheValue = "395"; //这里一般是 sql查询数据。 例：395 签到天数
                    CacheHelper.Add(cacheKey, cacheValue, cacheTime * 2); //日期设缓存时间的2倍，用于脏读。
                });
            }
            return cacheValue;
        }
    }
}