变量，在类或方法中哪个更好？

Question

just wondering which one of these would be the best to practice?

code 1:

public void push<T>(T pushthis)
{
    pusher pusher = new pusher();
    pusher.push(new System.Web.Script.Serialization.JavaScriptSerializer().Serialize(pushthis));
}

code 2:

public void push<T>(T pushthis)
{
    pusher pusher = new pusher();
    System.Web.Script.Serialization.JavaScriptSerializer serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
    pusher.push(serializer.Serialize(pushthis));
}

code 3:

public class pusher()
{
    System.Web.Script.Serialization.JavaScriptSerializer serializer = new System.Web.Script.Serialization.JavaScriptSerializer();

    public void push<T>(T pushthis)
    {
       pusher pusher = new pusher();                
       pusher.push(serializer.Serialize(pushthis));
    }
}

I want to know if better make a variable for serializer, and if yes where to put it, inside the method or inside the class And i will be using the push method many times, with just an instance of the class pusher.

And if possible, can you site some references for me to study for code optimization

Answer 1

The first and the second ways of coding the method are identical. The local variable is defined and used immediately; there are no other places where serializer is used.

The third way of coding reuses serializer across multiple invocations of pusher . It does not call the constructor of JavaScriptSerializer multiple times, and therefore may be more efficient.

You could possibly share JavaScriptSerializer among all instances of class pusher by making the serializer variable static . Unless you change configuration dynamically, for example by calling RegisterConverters , you may be able to reduce the number of invocations of the constructor further.

Answer 2

我不认为代码1和代码2有很大的不同。如果你多次使用push方法，那么使它成为类级变量而不是本地/方法级变量

Answer 3

Best thing to do is to measure performance.

I really doubt you'll see much difference, if any. When you create an object in a method it will go out of scope at the end of the method and be efficiently GC'd.

If you declare the JavaScriptSerializer as a field on the class you need to make sure that it is thread-safe if you'll be calling it concurrently.