To split only Chinese characters in java

Question

I am writing a java application; but stuck on this point.

Basically I have a string of Chinese characters with ALSO some possible Latin chars or numbers, lets say:

查詢促進民間參與公共建設法（210ＢＯＴ法）.

I want to split those Chinese chars except the Latin or numbers as "BOT" above. So, at the end I will have this kind of list:

[ 查, 詢, 促, 進, 民, 間, 參, 與, 公, 共, 建, 設, 法, （, 210, ＢＯＴ, 法, ）, ., ]

How can I resolve this problem (for java)?

Answer 1

Chinese characters lies within certain Unicode ranges:

• 2F00-2FDF: Kangxi
• 4E00-9FAF: CJK
• 3400-4DBF: CJK Extension

So all you basically need to do is to check if the character's codepoint lies within the known ranges. This example is a good starting point to write a stackbased parser/splitter, you only need to extend it to separate digits from latin letters, which should be obvious enough (hint: Character#isDigit()):

Set<UnicodeBlock> chineseUnicodeBlocks = new HashSet<UnicodeBlock>() {{
    add(UnicodeBlock.CJK_COMPATIBILITY);
    add(UnicodeBlock.CJK_COMPATIBILITY_FORMS);
    add(UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS);
    add(UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS_SUPPLEMENT);
    add(UnicodeBlock.CJK_RADICALS_SUPPLEMENT);
    add(UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION);
    add(UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS);
    add(UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A);
    add(UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_B);
    add(UnicodeBlock.KANGXI_RADICALS);
    add(UnicodeBlock.IDEOGRAPHIC_DESCRIPTION_CHARACTERS);
}};

String mixedChinese = "查詢促進民間參與公共建設法（210ＢＯＴ法）";

for (char c : mixedChinese.toCharArray()) {
    if (chineseUnicodeBlocks.contains(UnicodeBlock.of(c))) {
        System.out.println(c + " is chinese");
    } else {
        System.out.println(c + " is not chinese");
    }
}

Good luck.

Answer 2

Here's an approach I would take.

You can use Character.codePointAt(char[] charArray, int index) to return the Unicode value for a char in your char array.

You will also need a mapping of Latin Unicode characters.

If you look in the source of Character.UnicodeBlock, the full LATIN block is the interval [0x0000, 0x0249]. So basically you check if your Unicode code point is somewhere within that interval.

I suspect there is a way to just use a Character.Subset to check if it contains your char, but I haven't looked into that.