How can I detect japanese text in a Java string?

Question

I need to be able to detect Japanese characters in a Java string.

Currently I'm getting the UnicodeBlock and checking to see if it's equal to Character.UnicodeBlock.KATAKANA or Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS, but I'm not 100% that's going to cover everything.

Any suggestions?

Rakesh N Rakesh N · Accepted Answer · 2012-02-17T12:02:49

I use the following java method. Might not completely address your requirement though.

<!-- language: lang-java -->
/**
 * Returns if a character is one of Chinese-Japanese-Korean characters.
 * 
 * @param c
 *            the character to be tested
 * @return true if CJK, false otherwise
 */
private boolean isCharCJK(final char c) {
    if ((Character.UnicodeBlock.of(c) == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS)
            || (Character.UnicodeBlock.of(c) == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A)
            || (Character.UnicodeBlock.of(c) == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_B)
            || (Character.UnicodeBlock.of(c) == Character.UnicodeBlock.CJK_COMPATIBILITY_FORMS)
            || (Character.UnicodeBlock.of(c) == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS)
            || (Character.UnicodeBlock.of(c) == Character.UnicodeBlock.CJK_RADICALS_SUPPLEMENT)
            || (Character.UnicodeBlock.of(c) == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION)
            || (Character.UnicodeBlock.of(c) == Character.UnicodeBlock.ENCLOSED_CJK_LETTERS_AND_MONTHS)) {
        return true;
    }
    return false;
}

Futhermore, these seem they should work for Hiragana and Katakana characters:

private boolean isHiragana(final char c)
{
     return (Character.UnicodeBlock.of(c)==Character.UnicodeBlock.HIRAGANA);
}

private boolean isKatakana(final char c)
{
     return (Character.UnicodeBlock.of(c)==Character.UnicodeBlock.KATAKANA);
}

How can I detect japanese text in a Java string?

2 Answers