apollo-client/src/main/java/com/ctrip/framework/apollo/util/parser/Parsers.java/DurationParser/parseNumber
class DurationParser:    private static int parseNumber(String parsed, int multiplier) {
      // regex limits to [0-9]+
      if (parsed == null || parsed.trim().isEmpty()) {
        return 0;
      }
      return Integer.parseInt(parsed) * multiplier;
    }