使用Linq对Hashtable和Dictionary<T,T>查询的效率比较

近期做版本迭代任务，有一个在店铺头部展示店主所在的城市名称和省份名称的需求,店主信息表中保存了店主所在的城市Id和省份Id，由于原有业务复杂，要尽量减少Sql执行时间，所以不考虑join城市地区详细表。于是考虑在集合类中处理。

是选择Hashtable还是Dictionary<T,T>呢？于是做了一个测试，代码清单如下:

/// <summary>
    /// 城市信息
    /// </summary>
    public class CityInfo
    {
        public string CityName { get; set; }
        public string ProvinceName { get; set; }
    }
    /// <summary>
    /// 数据仓库和查找方法
    /// </summary>
    public static  class Respository
    {

        
        public static Hashtable Retrieve()
        {
            Hashtable data = new Hashtable();
            for (int i = 0; i < 100000; i++)
            {
             data.Add(i+1,"data"+i);
            }
            return data;
        }
        public static string Find(Hashtable data,int id)
        {
            var query = from item in data.Cast<DictionaryEntry>() where (int)item.Key == id select item.Value.ToString();
            return query.First();
        }


        public static Dictionary<int, string> SecondRetrieve()

        {
            Dictionary<int,string> data = new Dictionary<int,string>();
            for (int i = 0; i < 100000; i++)
            {
                data.Add(i + 1, "data" + i);
            }
            return data;
        }

        public static string SecondFind(Dictionary<int, string> data, int id)
        {
            var query = from item in data where (int)item.Key == id select item.Value;
            return query.First();
        }

        public static Dictionary<int, CityInfo> ThridRetrieve()
        {
            Dictionary<int, CityInfo> data = new Dictionary<int, CityInfo>();
            for (int i = 0; i < 100000; i++)
            {
                data.Add(i + 1,  new CityInfo { CityName="CityName"+i, ProvinceName="ProvinceName"+i  });
            }
            return data;
        }

        public static CityInfo ThridFind(Dictionary<int, CityInfo> data, int id)
        {
            var query = from item in data where (int)item.Key == id select item.Value;
            return query.First();
        }
    }

测试入口:

static void Main(string[] args)
        {
            {
                Stopwatch stwtotal = new Stopwatch();
                stwtotal.Start();
                Hashtable data = Respository.Retrieve();
                for (int i = 1; i < 20; i++)
                {
                    Stopwatch stw = new Stopwatch();
                    stw.Start();
                    Random r = new Random();
                    string result = Respository.Find(data, r.Next(1, 1000)*i);
                    stw.Stop();
                    Console.WriteLine(result + "   FirstFindExecuteTime:" + stw.Elapsed.TotalMilliseconds+"ms");
                }
                stwtotal.Stop();
                Console.WriteLine("测试数据总时间：" + stwtotal.Elapsed.TotalMilliseconds + "ms");
            }
            {
                Stopwatch stwtotal = new Stopwatch();
                stwtotal.Start();
                Dictionary<int, string> data = Respository.SecondRetrieve();
                for (int i = 1; i < 20; i++)
                {
                    Stopwatch stw = new Stopwatch();
                    stw.Start();
                    Random r = new Random();
                    string result = Respository.SecondFind(data, r.Next(1, 1000)*i);
                    stw.Stop();
                    Console.WriteLine(result + "   SecondFindExecuteTime:" + stw.Elapsed.TotalMilliseconds+"ms");
                }
                stwtotal.Stop();
                Console.WriteLine("测试数据总时间：" + stwtotal.Elapsed.TotalMilliseconds + "ms");
            }
            {
                Stopwatch stwtotal = new Stopwatch();
                stwtotal.Start();
                Dictionary<int, CityInfo> data = Respository.ThridRetrieve();
                for (int i = 1; i < 20; i++)
                {
                    Stopwatch stw = new Stopwatch();
                    stw.Start();
                    Random r = new Random();
                    CityInfo result = Respository.ThridFind(data, r.Next(1, 1000) * i);
                    stw.Stop();
                    Console.WriteLine(result.CityName + "   ThridFindExecuteTime:" + stw.Elapsed.TotalMilliseconds + "ms");
                }
                stwtotal.Stop();
                Console.WriteLine("真实数据初始化到查找结束总时间：" + stwtotal.Elapsed.TotalMilliseconds + "ms");
            }
            Console.ReadKey();
        }

测试结论：Dictionary<T,T>明显优于Hashtable

截图如下:

1.Hashtable

2Dictionary<int,string>

3,Dictionary<int,CityInfo>