1360. 日期之间隔几天

Java代码：

【DateFormat】DateFormat用于实现日期的格式化

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;  // 好像已过时

class Solution {
    public int daysBetweenDates(String date1, String date2) {
        DateFormat dft = new SimpleDateFormat("yyyy-MM-dd");
        long sum = 0;
        try {
            Date start = dft.parse(date1);
            Date end = dft.parse(date2);
            long startTimeMillion = start.getTime();
            long endTimeMillion = end.getTime();
            sum = endTimeMillion - startTimeMillion;  // 时间戳相差的毫秒数
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return Math.abs(Math.toIntExact(sum / 24 / 60 / 60 / 1000));
    }
}

Date 和 LocalDate 的区别

https://www.runoob.com/manual/jdk11api/java.base/java/time/LocalDate.html#parse(java.lang.CharSequence)

https://www.runoob.com/manual/jdk11api/java.base/java/time/temporal/ChronoUnit.html#DAYS

import java.time.LocalDate;
import java.time.temporal.ChronoUnit;

class Solution {
    public int daysBetweenDates(String date1, String date2) {
        LocalDate startDate = LocalDate.parse(date1);
        LocalDate endDate = LocalDate.parse(date2);

        long daysDiff = ChronoUnit.DAYS.between(startDate, endDate);
        
        return Math.abs((int)daysDiff);
    }
}