最快的字符串格式转换

Question

I have the following string: 20140420000001 I want to format it to: 2014-04-20+00:00:01

What is the fastest possible way to do this in Java?

Anything faster than this?

String dt = "20140420000001";
System.out.println(dt.substring(0, 4)+"-"+dt.substring(4, 6)+"-"+dt.substring(6, 8)+"+"+dt.substring(8, 10)+":"+dt.substring(10, 12)+":"+dt.substring(12, 14));

Answer 1

    return new String(new char[] {
            s.charAt(0), s.charAt(1), s.charAt(2), s.charAt(3),
            '-', s.charAt(4), s.charAt(5),
            '-', s.charAt(6), s.charAt(7),
            '+', s.charAt(8), s.charAt(9),
            ':', s.charAt(10), s.charAt(11),
            ':', s.charAt(12), s.charAt(13)
    });

Not too pretty, but there is hardly anything faster in pure Java.