Java如何在switch语句中使用全局变量

Question

I have three integer global variables:

   public static int a = 1;
   public static int b = 2;
   public static int c = 3;

I want to do:

int code = dis.readInt();
switch(code)
{
    case a: 
    ......
    break;
    case b:
    ......
    break;
    case c:
    ......
    break;
}

But it is not working, can anyone help? Thanks!

Answer 1

The Java switch statement can accept " Constant Expressions " and " Enum Constant Names ", as noted in section 14.11 of the Java Language Specification .

If you can provide a bit more context, a better solution to the problem may be available; otherwise, this is as close as you get in Java:

public class Constant
{
    public static final int a=1;
    public static final int b=2;
    public static final int c=3;

    public static void main(String[] args)
    {
        if(0 == args.length)
        {
            System.exit(-1);
        }
        String string=args[0];
        int value=Integer.parseInt(string);

        switch(value)
        {
            case a:
                System.out.println("It's an 'a'");
                break;
            case b:
                System.out.println("It's an 'b'");
                break;
            case c:
                System.out.println("It's an 'c'");
                break;
            default:
                System.out.println(String.format("It's a mystery '%s'",value));
                break;
        }
    }
}

Answer 2

Since you only have 1 character I wouldn't recommend using String, instead use char.

char string=args[0];

and then follow the answer Jan neilsen gave.