Java计算两个字符串日期之间的天数差

Java计算两个字符串日期之间的天数差

调用方法：

    public static void main(String[] args) throws ParseException {String a = "2017-12-01"; // 时间字符串String b = "2017-12-31";Long between_dayInteger = between_days(a, b);System.out.println(between_dayInteger);}

控制台输出：

封装方法：

public static Long between_days(String a, String b) {SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");// 自定义时间格式
Calendar calendar_a = Calendar.getInstance();// 获取日历对象Calendar calendar_b = Calendar.getInstance();Date date_a = null;Date date_b = null;try {date_a = simpleDateFormat.parse(a);//字符串转Datedate_b = simpleDateFormat.parse(b);calendar_a.setTime(date_a);// 设置日历
            calendar_b.setTime(date_b);} catch (ParseException e) {e.printStackTrace();//格式化异常
        }long time_a = calendar_a.getTimeInMillis();long time_b = calendar_b.getTimeInMillis();long between_days = (time_b - time_a) / (1000 * 3600 * 24);//计算相差天数return between_days;}