code: public static long convertTime(long sourceDuration, TimeUnit sourceUnit, TimeUnit destUnit) {
  		Assert.notNull(sourceUnit, "sourceUnit is null !");
  		Assert.notNull(destUnit, "destUnit is null !");
  		return destUnit.convert(sourceDuration, sourceUnit);
  	}
docs: 转换时间单位
  
  @param sourceDuration 时长
  @param sourceUnit 源单位
  @param destUnit 目标单位
  @return 目标单位的时长