LocalDateTime localDateTime = LocalDateTime.now();
 localDateTime= localDateTime.plusDays(1);//加一天

System.out.println("計算兩個時間的差：");
        String time2 = "2020-06-26 19:00:00";
        String time1 = "2020-06-26 19:00:30";

        DateTimeFormatter dtf2 = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        LocalDateTime end = LocalDateTime.parse(time1, dtf2);
       // LocalDateTime end = LocalDateTime.now();
        //LocalDateTime now = LocalDateTime.now();
        LocalDateTime now = LocalDateTime.parse(time2, dtf2);
        Duration duration = Duration.between(now,end);
        long days = duration.toDays(); //相差的天數
        long hours = duration.toHours();//相差的小時數
        long minutes = duration.toMinutes();//相差的分鐘數
        long millis = duration.toMillis();//相差毫秒數
        long nanos = duration.toNanos();//相差的納秒數
        System.out.println(now);
        System.out.println(end);

        System.out.println("發(fā)送短信耗時【 "+days+"天："+hours+" 小時："+minutes+" 分鐘："+millis+" 毫秒："+nanos+" 納秒】");

        String time1 = "2019-06-26 19:00:00";
        DateTimeFormatter dtf2 = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        LocalDateTime localDateTime = LocalDateTime.parse(time1, dtf2);
        System.out.println(localDateTime.isBefore(LocalDateTime.now()));//你的時間在當前時間之前是true
        System.out.println(localDateTime.isAfter(LocalDateTime.now()));//在當前時間之后是false