java两个时间比较的几种方式

@Test
public void test(){
    LocalDateTime localDateTime = LocalDateTime.parse("2023-03-24T10:00:00");
  // 或者这样写
    // LocalDateTime localDateTime = LocalDateTime.of(2023, 3, 24, 10 , 0, 0);
    // 给定时间 +7 天
    localDateTime = localDateTime.plus(7, ChronoUnit.DAYS);
    System.out.println(localDateTime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
    LocalDateTime now = LocalDateTime.now();
    System.out.println(now.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
  // 判断 给定时间 +7 天  是否在 当前时间 之前
    System.out.println(localDateTime.isBefore(now));
}

@Test
public void test() {
    LocalDate from = LocalDate.of(2023, 3, 24);
    long day = LocalDate.now().toEpochDay() - from.toEpochDay();
    System.out.println("距离当前多少日：" + day);
}

@Test
public void test() {
    // 给定时间
    Calendar calendar = Calendar.getInstance();
    // 月份为当前月-1
    calendar.set(2023, Calendar.MARCH, 24, 10 , 0, 0);
    //当前时间 减去 给定时间 是否大于7天
    long now = System.currentTimeMillis();
    long time = calendar.getTimeInMillis();
    long days = (now - time) / (1000 * 3600 * 24);
    System.out.println(days);
}