Java fastest way to concatenate strings, integers and floats

Question

What is the most performant way to build strings from strings, integers and floats? currently I'm doing this and it uses a lot of cpu time.

String frame = this.frameTime + ":" +
    this.player.vertices[0].x + "," +
    this.player.vertices[0].y + "," +
    this.player.activeAnimId + "," +
    (int)this.player.virtualSpeed + "," +
    this.map.getCurrentTime() + 
    (this.player.frameSound == -1 ? "" : "," + this.player.frameSound) +
    (this.player.frameDecal.equals("") ? "" : "," + this.player.frameDecal) +
    ";";

Is there a way to do this faster?

Answer 1

That should already be fast - it'll use StringBuilder internally for concatenation. Arguably using StringBuilder explicitly could eliminate the concatenation of empty strings, but it's not likely to make a big difference.

How often are you doing this, anyway? It must be pretty often, for it to be a bottleneck... do you really need to do it that often?

EDIT: For those who are saying "Use StringBuilder, it'll be faster" - consider this code:

public class Test
{
    public static void main(String[] args)
    {
        int x = 10;
        int y = 20;
        int z = 30;
        String foo = x + "," + y + "," + z + ";";
        System.out.println(foo);
    }
}

Compile that, then use javap -c to see what the compiler generates...

Answer 2

Use a StringBuilder.

String string = new StringBuilder("abcd").append(23).append(false).append("xyz").toString();

Answer 3

You could try using a StringBuilder.

(However, most Java compilers worth their salt will automatically optimize the code you've listed to use StringBuilder behind the scenes.)