判断日期是否是今天，昨天

利用 LocalDate 来判断，获取今天和昨天的日期

        LocalDate today = LocalDate.now();
        LocalDate yesterday = today.minus(1, ChronoUnit.DAYS);

将要判断的日期也转换为 LocalDate 

        Calendar calendar = Calendar.getInstance();
        calendar.setTime(legacyDate);
        LocalDate local = LocalDate.of(calendar.get(Calendar.YEAR), 
                calendar.get(Calendar.MONTH) + 1, 
                calendar.get(Calendar.DAY_OF_MONTH));

判断是否相等，直接使用  isEqual  函数

System.out.println(today.isEqual(local));