三種方式實例化一個類的性能情況

源內容：http://www.cnblogs.com/shouce/p/5558095.html#undefined

下麵的內容是根據“源內容”進行了整改、補充。

三種方式實例化一類，包括無參數構造形式與有參數構造形式性能測試。

1. 使用new關鍵字創建類實例（常用方式）。
2. 使用Activator激活器類創建類實例（Activator用以在本地或從遠程創建對象類型，或獲取對現有遠程對象的引用）。
3. 使用Assembly程式集創建類實例（Assembly表示一個程式集，它是一個可重用、無版本衝突並且可自我描述的公共語言運行庫應用程式構造塊。該類可以載入程式集、瀏覽程式集的元數據和構成部分、發現程式集中包含的類型以及創建這些類型的實例）。

測試環境：

　　1） Visual studio 2015 Community

　　2） Windows 10 Profession

　　3） Memory 6G，CPU Inter-Core-i3-3220 @ 3.3GHz

測試代碼如下,分別為介面、介面實現類、實例化類的創建、執行測試方法

/// <summary>
/// 職業、行業
/// </summary>
public interface IProfession
{
    string Name { get; }
    string MostMeaningThing();
}
/// <summary>
/// 工人、藍領
/// </summary>
public class Worker : IProfession
{
    public Worker(string name)
    {
        Name = name;
    }

    public Worker()
    {
        
    }

    public string Name { get; private set; }

    public string MostMeaningThing()
    {
        return "挖掘機哪家強山東找藍翔";
    }
} 
public class InstanceClass
{
    //可根據自己的項目名稱進行修改
    private string className = "TestProblem.Worker";
    //執行次數
    private int time = 100000;
    /// <summary>
    /// 是否執行有參數構造函數
    /// </summary>
    private bool hasParameters;

    public InstanceClass(bool hasParameters)
    {
        this.hasParameters = hasParameters;
    }

    /// <summary>
    /// 通過new關鍵字創建
    /// </summary>
    public void CreateByNew()
    {
        IProfession profession;
        Stopwatch watch = new Stopwatch();
        watch.Start();
        for (int i = 0; i < time; i++)
        {
            profession = hasParameters ? new Worker("工人-New-" + i) : new Worker();
        }
        watch.Stop();
        Console.Write(watch.ElapsedMilliseconds.ToString().PadLeft(5));

    }
    /// <summary>
    /// 通過Activator控制類創建
    /// </summary>
    public void CreateByActivator()
    {
        Type type = Type.GetType(className);
        IProfession profession;
        Stopwatch watch = new Stopwatch();
        watch.Start();
        for (int i = 0; i < time; i++)
        {
            object obj = hasParameters ? Activator.CreateInstance(type, "工人-Activator-" + i) : Activator.CreateInstance(type);
            profession = obj as IProfession;
        }
        watch.Stop();
        Console.Write(watch.ElapsedMilliseconds.ToString().PadLeft(5));
    }
    /// <summary>
    /// 通過Assembly控制類創建
    /// </summary>
    public void CreateByAssembly()
    {
        Assembly assembly = Assembly.GetAssembly(Type.GetType(className));
        IProfession profession;
        Stopwatch watch = new Stopwatch();
        watch.Start();
        for (int i = 0; i < time; i++)
        {
            object obj = hasParameters ?
                assembly.CreateInstance(className, true, BindingFlags.Default, null, new object[] { "工人-Assembly-" + i }, CultureInfo.CurrentCulture, null)
                : assembly.CreateInstance(className);
            profession = obj as IProfession;
        }
        watch.Stop();
        Console.Write(watch.ElapsedMilliseconds.ToString().PadLeft(5));
    }
    /// <summary>
    /// For迴圈，替代代碼中多次手寫類似的For迴圈代碼
    /// </summary>
    /// <param name="time">迴圈次數</param>
    /// <param name="action">委托</param>
    public static void ForLoop(int time, Action<int> action)
    {
        for (int i = 0; i < time; i++)
        {
            action(i);
        }
    }
    /// <summary>
    /// For迴圈，封裝For迴圈代碼執行
    /// </summary>
    /// <param name="time">迴圈次數</param>
    /// <param name="action">委托，函數指針</param>
    public static void ForLoop(int time, Action action)
    {
        for (int i = 0; i < time; i++)
        {
            action();
        }
    }
}
/// <summary>
/// 執行十次的十萬個創建類實例
/// </summary>
private static void ExecuteLakh()
{
    bool hasParameters = true;
    Console.WriteLine("實例化一個類({0}參數構造)的性能比較（單位：毫秒）", hasParameters ? "有" : "無");
    Console.Write("\t\t\t");
    InstanceClass.ForLoop(10, i => Console.Write("{0:G}", (i + 1).ToString().PadLeft(5)));
    Console.WriteLine();
    InstanceClass instanceClass = new InstanceClass(hasParameters);
    Console.Write("CreateByNew".PadRight(24));
    InstanceClass.ForLoop(10, () => instanceClass.CreateByNew());
    Console.WriteLine();
    Console.Write("CreateByActivator".PadRight(24));
    InstanceClass.ForLoop(10, () => instanceClass.CreateByActivator());
    Console.WriteLine();
    Console.Write("CreateByAssembly".PadRight(24));
    InstanceClass.ForLoop(10, () => instanceClass.CreateByAssembly());
    Console.WriteLine();
}

測試結果如下：