怎么在字符串中寻找${demo}

如何在字符串中寻找${demo}

public static void main(String[] args) {        String formula = "XXXX${date}V${demo}VVV";        String reg = "\\$\\{[^}]+\\}";        Pattern p = Pattern.compile(reg);        Matcher matcher = p.matcher(formula);        while (matcher.find()) {            System.out.println(matcher.group());        }    }