如何过滤Java String以仅获取字母字符？

Question

I'm generating a XML file to make payments and I have a constraint for user's full names. That param only accept alphabet characters (a-ZAZ) + whitespaces to separe names and surnames.

I'm not able to filter this in a easy way, how can I build a regular expression or a filter to get my desireable output?

Example:

'Carmen López-Delina Santos' must be 'Carmen LopezDelina Santos'

I need to transform vowels with decorations in single vowels as follows: á > a, à > a, â > a, and so on; and also remove special characters as dots, hyphens, etc.

Thanks!

Answer 1

You can first use a Normalizer and then remove the undesired characters:

String input = "Carmen López-Delina Santos";
String withoutAccent = Normalizer.normalize(input, Normalizer.Form.NFD);
String output = withoutAccent.replaceAll("[^a-zA-Z ]", "");
System.out.println(output); //prints Carmen LopezDelina Santos

Note that this may not work for all and any non-ascii letters in any language - if such a case is encountered the letter would be deleted. One such example is the Turkish i .

The alternative in that situation is probably to list all the possible letters and their replacement...

Answer 2

You can use this removeAccents method with a later replaceAll with [^A-Za-z ] :

public static String removeAccents(String text) {
  return text == null ? null :
    Normalizer.normalize(text, Form.NFD)
        .replaceAll("\\p{InCombiningDiacriticalMarks}+", "");
}

The Normalizer decomposes the original characters into a combination of a base character and a diacritic sign (this could be multiple signs in different languages). á , é and í have the same sign: 0301 for marking the ' accent.

The \\p{InCombiningDiacriticalMarks}+ regular expression will match all such diacritic codes and we will replace them with an empty string.

And in the caller:

String original = "Carmen López-Delina Santos";
String res = removeAccents(original).replaceAll("[^A-Za-z ]", "");
System.out.println(res);

See IDEONE demo