Is there replaceLast() in Java? I saw there is replaceFirst().

EDIT: If there is not in the SDK, what would be a good implementation?

解决方案

It could (of course) be done with regex:

public class Test {

public static String replaceLast(String text, String regex, String replacement) {

return text.replaceFirst("(?s)"+regex+"(?!.*?"+regex+")", replacement);

}

public static void main(String[] args) {

System.out.println(replaceLast("foo AB bar AB done", "AB", "--"));

}

}

although a bit cpu-cycle-hungry with the look-aheads, but that will only be an issue when working with very large strings (and many occurrences of the regex being searched for).

A short explanation (in case of the regex being AB):

(?s) # enable dot-all option

A # match the character 'A'

B # match the character 'B'

(?! # start negative look ahead

.*? # match any character and repeat it zero or more times, reluctantly

A # match the character 'A'

B # match the character 'B'

) # end negative look ahead

EDIT

Sorry to wake up an old post. But this is only for non-overlapping instances.

For example .replaceLast("aaabbb", "bb", "xx"); returns "aaaxxb", not "aaabxx"

True, that could be fixed as follows:

public class Test {

public static String replaceLast(String text, String regex, String replacement) {

return text.replaceFirst("(?s)(.*)" + regex, "$1" + replacement);

}

public static void main(String[] args) {

System.out.println(replaceLast("aaabbb", "bb", "xx"));

}

}