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Date
date_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;
}