無處不在的HttpContext

由於ASP.NET提供了靜態屬性HttpContext.Current，因此獲取HttpContext對象就非常方便了。
也正是因為這個原因，所以我們經常能見到直接訪問HttpContext.Current的代碼：

public class Class1
{
    public Class1()
    {
        string file = HttpContext.Current.Request.MapPath("~/App_Data/xxxxxx.xml");

        string text = System.IO.File.ReadAllText(file);

        //..........其它的操作
    }

    // 或者在一些方法中直接使用HttpContext.Current
    public void XXXXX()
    {
        string url = HttpContext.Current.Request.RawUrl;

        string username = HttpContext.Current.Session["username"].ToString();

        string value = (string)HttpContext.Current.Items["key"];
    }

    // 甚至還設計成靜態屬性
    public static string XXX
    {
        get
        {
            return (string)HttpContext.Current.Items["XXX"];
        }
    }
}

這樣的代碼，經常能在類庫項目中看到，由此可見其泛濫程度。

難道這些代碼真的沒有問題嗎？
有人估計會說：我寫的代碼是給ASP.NET程序使用的，又不是給控制臺程序使用，所以沒有問題。

真的是這樣嗎？

http://tieba.baidu.com/p/5632998173
http://tieba.baidu.com/p/5634106628
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www.cnblogs.com/baidu1/p/8721564.html

HttpContext.Current並非無處不在