java计算两个字符串日期的相差天数【jdk8新特性LocalDateTime和Hutool两种方式实现】

<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.7.18</version>
</dependency>

public static long compareTime(String dateStr1,String dateStr2){
    Date date1 = DateUtil.parse(dateStr1);
    Date date2 = DateUtil.parse(dateStr2);
    return DateUtil.between(date1, date2, DateUnit.DAY);
}

public static void main(String[] args) {
  String dateStr1 = "2021-01-01";
    String dateStr2 = "2021-01-05";
    long compareTime = compareTime(dateStr1, dateStr2);//4
}

  String dateStr1 = "2021-01-01";
    String dateStr2 = "2021-01-05";
    LocalDate parse = LocalDate.parse(dateStr1);
    LocalDate parse1 = LocalDate.parse(dateStr2);
    long between = ChronoUnit.DAYS.between(parse, parse1);//4