reformat iso date

I was given a tiny challenge, write a function that changes "yyyy-mm-dd HH:MM" into "mm/dd/yyyy".

First I wrote a test:

package org.yi.happy;

import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class DateReformatTest {
    @Test
    public void test1() {
        String have = DateReformat.isoToAccess("2010-02-01 14:40");

        assertEquals("02/01/2010", have);
    }

}

Then I wrote the code, and used a regular expression to do the work:

package org.yi.happy;

public class DateReformat {

    public static String isoToAccess(String value) {
        return value.replaceAll(
                "^(\\d\\d\\d\\d)-(\\d\\d)-(\\d\\d) \\d\\d:\\d\\d$",
                "$2/$3/$1");
    }

}

All it does is capture some groups of digits, then re-arranges them. If it does not match it just returns the original string.