JAVA基础------实现日期差值的计算

我就是我 2022-06-03 03:00 217阅读 0赞

自己写了一个计算日期差值的小功能

考虑到闰年及非闰年  
传入格式为”YYYY-MM-DD”或”YYYY-M-D”的字符串即可，没有实现对传入参数非日期格式或数据的检查。

date1参数为当前时间  
date2参数为设定时间

class cDate {
        public String calculatingDateDifference(String date1, String date2) {    // date1 当前时间 date2 设定时间
    
            String[] a = date1.split("-");
            String[] b = date2.split("-");
            int month1 = Integer.parseInt(a[1].trim());
            int month2 = Integer.parseInt(b[1].trim());
            int dofm1 = Integer.parseInt(a[2].trim());    // day of month
            int dofm2 = Integer.parseInt(b[2].trim());
            int year1 = Integer.parseInt(a[0]);
            int year2 = Integer.parseInt(b[0]);
    
            int day1 = calculatingDays(year1, month1, dofm1);    // day of year
            int day2 = calculatingDays(year2, month2, dofm2);
    
            System.out.println("date1:"+ date1 +" month1:" + month1 + " dofm1:" + dofm1 + " year1:" + year1 + " day1:" + day1);
            System.out.println("date2:"+ date2 +" month2:" + month2 + " dofm2:" + dofm2 + " year2:" + year2 + " day2:" + day2);
            if (year1 != year2)   //不同年
            {
                if (year1 > year2) {
                    if (month1 == month2 && dofm1 == dofm2) {
                        return year1 - year2 + "年前的今天";
                    } else {
                        int timeDistance = 0;
                        for (int i = year2; i < year1; i++) {
                            if (i % 4 == 0 && i % 100 != 0 || i % 400 == 0)    //闰年
                            {
                                timeDistance += 366;
                            } else    //不是闰年
                            {
                                timeDistance += 365;
                            }
                        }
                        return "距今已过去" + (timeDistance + (day1 - day2)) + "天";    // 把年累加到相同(计算一年天数*年数) + 一年中两天的差值
                    }
                } else if (year2 > year1) {
                    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;
                        }
                    }
                    if (month1 == month2 && dofm1 == dofm2) {
                        return year2 - year1 + "年后的今天,还有" + (timeDistance + day2 - day1) + "天";
                    }
                    return "距离设定时间还有" + (timeDistance + day2 - day1) + "天";
                }
    
    
            } else {    //同一年
                if (day1 > day2) {
                    return "已经过去" + (day1 - day2) + "天";
                } else if (day1 == day2) {
                    return "就是今天";
                } else {
                    return "还有" + (day2 - day1) + "天";
                }
            }
            return "我已经被判断日期绕晕了";
        }
    
        public int calculatingDays(int y, int m, int d) {    // 返回day of year
            m = m-1;
            int dayOfYear = 0;
            switch (m) {    // 利用case选择 累加
                case 11:
                    dayOfYear = dayOfYear + 30;
                case 10:
                    dayOfYear += 31;
                case 9:
                    dayOfYear += 30;
                case 8:
                    dayOfYear += 31;
                case 7:
                    dayOfYear += 31;
                case 6:
                    dayOfYear += 30;
                case 5:
                    dayOfYear += 31;
                case 4:
                    dayOfYear += 30;
                case 3:
                    dayOfYear += 31;
                case 2:
                    if (y % 4 == 0 && y % 100 != 0 || y % 400 == 0)    //闰年
                    {
                        dayOfYear += 29;
                    } else {    // 不是闰年
                        dayOfYear += 28;
                    }
                case 1:
                    dayOfYear += 31;
                case 0:
                    dayOfYear += 0;
            }
            return dayOfYear + d;
        }
    }
    
    public class Test {
    
        public static void main(String[]agrs)
        {
            cDate cdate = new cDate();
            System.out.println(cdate.calculatingDateDifference("2017-12-1", "2018-1-1"));    // 填入测试数据
            System.out.println("HelloWorld!");
        }
    }

![Exler][]

![Exler][Exler 1]

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若发现代码有错误的地方或是有更好实现方法的，欢迎讨论及分享，谢谢。

[Exler]: /images/20220603/fceef146068c4050b36100cb5b000996.png
[Exler 1]: /images/20220603/af4dd570c4114d5488d54876c9e98ef9.png