String input = "ABCD1234BCDE";
        String mode = "BCD";

        Pattern pattern = Pattern.compile(mode);
        int count = 0;
        Matcher matcher = pattern.matcher(input);
        while(matcher.find()) {
            count++;
        }

匹配到两次就会退出while循环

注意不能这么写，这么写永远退不出来

while(pattern.matcher(input).find()) {
            count++;
        }