Detecting Japanese characters in Java strings

Question

I am trying to detect if a java string contains Japanese characters. Since it does not matter to me if the characters form a grammatically correct sentence I thought I'd use a regex to match any Japanese character in the string like so:

package de.cg.javatest;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class JavaTest {

    public static void main(String[] args) {
        String aString = "なにげない日々。";
        Pattern pat = Pattern.compile("[\\p{InHiragana}]");
        Matcher m = pat.matcher(aString);
        System.out.println(m.matches()); // false
    }
}

However, the print statement always shows false. I have tried altering the pattern to

[\\p{IsHiragana}]
[\\p{InHiragana}]+

and I have also entered the code points manually. Is there something I am missing, or do I have to take another approach?

Answer 1

Matcher.matches returns true only when the pattern matches the whole string. As Anonymous commented, not all character are Hiragana characters.

By changing the pattern as following, you can check if there's any Hiragana.

Pattern pat = Pattern.compile(".*\\p{InHiragana}.*");

By using Matcher.find, you don't need to modify the pattern.

Pattern pat = Pattern.compile("\\p{InHiragana}");  // [..] is not needed.
Matcher m = pat.matcher(aString);
System.out.println(m.find()); // true