docs: public static String getAllFirstLetter(String chinese) {
  		if (StrUtil.isBlank(chinese)) {
  			return StrUtil.EMPTY;
  		}
  
  		int len = chinese.length();
  		final StrBuilder strBuilder = new StrBuilder(len);
  		for (int i = 0; i < len; i++) {
  			strBuilder.append(getFirstLetter(chinese.charAt(i)));
  		}
  
  		return strBuilder.toString();
  	}