java计算两个日期之间相隔的月份（向下取整）

最近需求里面有个需要计算两个日期之间相隔的月份，写起来还挺繁琐，需要将各种情况都要考虑到，写了一个作为以后自己的工具吧。

 1 //获取哪一天
 2     public static int getDay(Date date) {
 3         Calendar calendar = Calendar.getInstance();
 4         calendar.setTime(date);
 5         return calendar.get(Calendar.DATE);
 6     }
 7 
 8     /**
 9      * 返回日期的月份，1-12,即yyyy-MM-dd中的MM
10      *
11      * @param date
12      * @return
13      */
14     public static int getMonth(Date date) {
15         Calendar calendar = Calendar.getInstance();
16         calendar.setTime(date);
17         return calendar.get(Calendar.MONTH) + 1;
18     }
19 
20     /**
21      * 返回日期的年,即yyyy-MM-dd中的yyyy
22      *
23      * @param date
24      *            Date
25      * @return int
26      */
27     public static int getYear(Date date) {
28         Calendar calendar = Calendar.getInstance();
29         calendar.setTime(date);
30         return calendar.get(Calendar.YEAR);
31     }
32     public static int calDiffMonth(String startDate,String endDate) {
33         int result=0;
34         try {
35             SimpleDateFormat sfd=new SimpleDateFormat("yyyyMMdd");
36             Date start = sfd.parse(startDate);
37             Date end = sfd.parse(endDate);
38             int startYear=getYear(start);
39             int startMonth=getMonth(start);
40             int startDay=getDay(start);
41             int endYear=getYear(end);
42             int endMonth=getMonth(end);
43             int endDay=getDay(end);
44             
45             Calendar calendar2= Calendar.getInstance();
46             calendar2.setTime(start);
47             int maxDay = calendar2.getActualMaximum(Calendar.DAY_OF_MONTH);//获取起始日期所在月的最后一天
48             Calendar calendar3 = Calendar.getInstance();
49             calendar3.setTime(end);
50             int maxEndDay = calendar3.getActualMaximum(Calendar.DAY_OF_MONTH);//获取结束日期所在月的最后一天
51             if(startDay == maxDay){//起始日期是在月末
52                 if(maxEndDay==endDay){
53                     result=(endYear-startYear)*12+endMonth-startMonth;
54                 }else {
55                     result=(endYear-startYear)*12+endMonth-startMonth-1;
56                 }
57             }else if(endDay==maxEndDay){//结束日期是在月末
58                 result=(endYear-startYear)*12+endMonth-startMonth;
59             }else {
60                 if (endDay >= startDay) {
61                     result=(endYear-startYear)*12+endMonth-startMonth;
62                 }else {
63                     result=(endYear-startYear)*12+endMonth-startMonth-1;
64                 }
65             }
66         } catch (Exception e) {
67             e.printStackTrace();
68         }
69         return result;
70     }
71 
72 
73     public static void main(String[] args) {
74         int i = calDiffMonth("20171030", "20180228");
75         System.out.println(i);
76     }

 

posted @ 2018-07-03 15:33  恋在那时  阅读(2697)  评论(0)  编辑  收藏  举报