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
 1 public class test {
 2     public static int b;
 3     public static void main(String[] args) {13 
14         String s1="2020-05-06";
15         String s2="2020-05-07";
16         SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
17         try {
18             Date date = simpleDateFormat.parse(s1);
19             Date date1 = simpleDateFormat.parse(s2);
20             int i = differentDays(date,date1);
21             System.out.println(i+1);
22         } catch (ParseException e) {
23             e.printStackTrace();
24         }
25 
26     }
27 
28     /**
29      * date2比date1多的天数
30      * @param date1
31      * @param date2
32      * @return
33      */
34     public static int differentDays(Date date1, Date date2)
35     {
36         Calendar cal1 = Calendar.getInstance();
37         cal1.setTime(date1);
38 
39         Calendar cal2 = Calendar.getInstance();
40         cal2.setTime(date2);
41         int day1= cal1.get(Calendar.DAY_OF_YEAR);
42         int day2 = cal2.get(Calendar.DAY_OF_YEAR);
43 
44         int year1 = cal1.get(Calendar.YEAR);
45         int year2 = cal2.get(Calendar.YEAR);
46         if(year1 != year2)   //同一年
47         {
48             int timeDistance = 0 ;
49             for(int i = year1 ; i < year2 ; i ++)
50             {
51                 if(i%4==0 && i%100!=0 || i%400==0)    //闰年
52                 {
53                     timeDistance += 366;
54                 }
55                 else    //不是闰年
56                 {
57                     timeDistance += 365;
58                 }
59             }
60 
61             return timeDistance + (day2-day1) ;
62         }
63         else    //不同年
64         {
65             return day2-day1;
66         }
67     }
68 }