判斷字符串中是否含有4字節字符（UTF8編碼）

閒話少說直接上代碼

    public static boolean isContainSpecialChar(String str) {
        if(StringUtils.isEmpty(str)){
            return false;
        }
        try {
            byte[] bytes = str.getBytes("UTF-8");
            for (int i = 0; i < bytes.length; i++) {
                if(isStartWithOver3Byte(bytes[i])){
                    return true;
                }
            }
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return false;

    }

    /**
     *  判斷字節範圍是否在四，五，六範圍內
     *
     * 1字節 0xxxxxxx
     * 2字節 110xxxxx 10xxxxxx
     * 3字節 1110xxxx 10xxxxxx 10xxxxxx
     * 4字節 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
     * 5字節 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
     * 6字節 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
     * @param b
     * @return
     */

    public static boolean isStartWithOver3Byte(byte b) {
        int unsignByte = Byte.toUnsignedInt(b);
        return (0xf0 <= unsignByte && unsignByte <= 0xf7) ||//4字節開頭
            (0xf8 <= unsignByte && unsignByte <= 0xfb) ||//5字節開頭
            (0xfc <= unsignByte && unsignByte <= 0xfd);//6字節開頭
    }



    public static void main(String[] args){
        String str="€😘jekj，fj€dks@";//笑臉4個字節
        String str2="⏰kjsfjfjfj";//鬧鐘三個字節
        String str3="€";//三個字節
        System.out.println(isContainSpecialChar(str));
        System.out.println(isContainSpecialChar(str2));
        System.out.println(isContainSpecialChar(str3));
    }