### Question:
IdUtils { public static String makeSn() { return DateFormatUtils.format(System.currentTimeMillis(), "yyyyMMddHHmmssSSS"); }  static String makeUUID(); static String makeID(String bizCode); static String makeID(String bizCode, String serverId); static String makeSn(); static String makeSnRandom();  }### Answer:
@Test public void testMakeSn() { String s = IdUtils.makeSn(); System.out.println(s); Assertions.assertEquals(17, s.length()); }