字符串实习.NET Framework中 - 有什么好处以及何时使用实习 [英] String interning in .Net Framework - What are the benefits and when to use interning

问题描述

我想知道的过程和字符串的内部实习具体到.NET框架。也想知道用实习和场景/情况下，我们应该使用字符串实习来提高性能的好处。虽然我研究的杰弗里Richter的CLR书实习，但我仍然感到困惑，想知道它的更多细节。

问一个具体问题与样品$ C $如下：C：

 私人无效治法（）
{
    字符串s =字符串; //行1  - 实习文字作为答案解释

    //s.intern（）; //线2  -  3行中会发生什么，如果我们去掉这一行，会不会有什么区别？
}

私人布尔方法b（字符串compareThis）
{
    如果（compareThis ==字符串）// 3号线 - 将这一行使用实习（有和没有取消注释第2行以上）？
    {
        返回true;
    }
    返回false;
}
 

解决方案

实习是内部实现细节。 不像拳击的，我不认为有任何好处的知道的比你看过的更丰富的书。

微优化实习字符串的好处是手动的最小，因此一般不推荐。

这可能是这样描述的：

 类节目
{

    常量字符串SomeString =一些字符串; //被拘留

    静态无效的主要（字串[] args）
    {


        尝试
        {
            VAR S1 = SomeString; //利用实习字符串
            VAR S2 = SomeString; //利用实习字符串
            VAR S =字符串;
            VAR S3 =一些+ S; //没有实习

            Console.WriteLine（S1 == S2）; //使用实习比较
            Console.WriteLine（S1 == S3）; //不要使用实习比较


        }
        赶上（例外五）
        {

            Console.WriteLine（e.ToString（））;
        }


        Console.Read（）;
    }
}
 

I want to know the process and internals of string interning specific to .Net framework. Would also like to know the benefits of using interning and the scenarios/situations where we should use string interning to improve the performance. Though I have studied interning from the Jeffery Richter's CLR book but I am still confused and would like to know it in more detail.

[Editing] to ask a specific question with a sample code as below:

private void MethodA()
{
    string s = "String"; // line 1 - interned literal as explained in the answer        

    //s.intern(); // line 2 - what would happen in line 3 if we uncomment this line, will it make any difference?
}

private bool MethodB(string compareThis)
{
    if (compareThis == "String") // line 3 - will this line use interning (with and without uncommenting line 2 above)?
    {
        return true;
    }
    return false;
}

解决方案

Interning is an internal implementation detail. Unlike boxing, I do not think there is any benefit in knowing more than what you have read in Richer's book.

Micro-optimisation benefits of interning strings manually are minimal hence is generally not recommended.

This probably describes it:

class Program
{

    const string SomeString = "Some String"; // gets interned

    static void Main(string[] args)
    {


        try
        {
            var s1 = SomeString; // use interned string
            var s2 = SomeString; // use interned string
            var s = "String";
            var s3 = "Some " + s; // no interning 

            Console.WriteLine(s1 == s2); // uses interning comparison
            Console.WriteLine(s1 == s3); // do NOT use interning comparison


        }
        catch (Exception e)
        {

            Console.WriteLine(e.ToString());
        }


        Console.Read();
    }
}

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