java中两个日期之间的天数

比如：2020-05-06  到 2020-05-07

返回两天    代码如下

public class test {
    public static int b;
    public static void main(String[] args) {13 
        String s1="2020-05-06";
        String s2="2020-05-07";
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
        try {
            Date date = simpleDateFormat.parse(s1);
            Date date1 = simpleDateFormat.parse(s2);
            int i = differentDays(date,date1);
            System.out.println(i+1);
        } catch (ParseException e) {
            e.printStackTrace();
        }

    }

    /**
     * date2比date1多的天数
     * @param date1
     * @param date2
     * @return
     */
    public static int differentDays(Date date1, Date date2)
    {
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);

        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        int day1= cal1.get(Calendar.DAY_OF_YEAR);
        int day2 = cal2.get(Calendar.DAY_OF_YEAR);

        int year1 = cal1.get(Calendar.YEAR);
        int year2 = cal2.get(Calendar.YEAR);
        if(year1 != year2)   //同一年
        {
            int timeDistance = 0 ;
            for(int i = year1 ; i < year2 ; i ++)
            {
                if(i%4==0 && i%100!=0 || i%400==0)    //闰年
                {
                    timeDistance += 366;
                }
                else    //不是闰年
                {
                    timeDistance += 365;
                }
            }

            return timeDistance + (day2-day1) ;
        }
        else    //不同年
        {
            return day2-day1;
        }
    }
}