我应该使用静态方法还是静态字段

Question

I want to declare some static variables and use them a lot in my code, so in this example if I want to change the phone number I will change it in one place:

public class AppInformation{
    static String phone_number="44444444";
}

So now I could get the phone_number by calling the class : AppInformation.phone_number ;

Another solution:

public class AppInformation {

    public static String get_phone_number(){
        return "44444444";
    } 
}

Now I could call the method: AppInformation.get_phone_number ();

Actually I prefer the second method because it is thread safe!

Is this correct? Are there any other suggestions?

Answer 1

Declare it as public static final String PHONE_NUMBER = "44444444" . Since you can only read this variable, it is thread-safe.

Why I named it PHONE_NUMBER , not phoneNumber (or breaking all known to me Java conventions phone_number ), is explained here .

Answer 2

You can declare it as

static final String phone_number="44444444"; And do not worry about threadsafe anymore :)

Answer 3

What you are saying is that you want a constant, which in Java, is commonly expressed like this:

public class AppInformation
{
  public static final String PHONE_NUMBER = "44444444";
}

Note, in your example you've missed:

• the access modifier , which in the case of a class means the value would be package private.
• the final keywork, which means the value could be modified when the program is running.