java android 计算两个日期之间的天数

 

第一种：

public class Time {

    public static void main(String[] args) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
           Date date_start = null;
           Date date_end = null;
        try {
        date_start = sdf.parse("2013-10-24");
        date_end = sdf.parse("2013-11-20");
        } catch (java.text.ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        }
          System.out.println(getGapCount(date_start,date_end));
    }
    
    /**
    * 获取两个日期之间的间隔天数
    * @return
    */
    public static int getGapCount(Date startDate, Date endDate) {
            Calendar fromCalendar = Calendar.getInstance();
            fromCalendar.setTime(startDate);
            fromCalendar.set(Calendar.HOUR_OF_DAY, 0);
            fromCalendar.set(Calendar.MINUTE, 0);
            fromCalendar.set(Calendar.SECOND, 0);
            fromCalendar.set(Calendar.MILLISECOND, 0);
    
            Calendar toCalendar = Calendar.getInstance();
            toCalendar.setTime(endDate);
            toCalendar.set(Calendar.HOUR_OF_DAY, 0);
            toCalendar.set(Calendar.MINUTE, 0);
            toCalendar.set(Calendar.SECOND, 0);
            toCalendar.set(Calendar.MILLISECOND, 0);
    
            return (int) ((toCalendar.getTime().getTime() - fromCalendar.getTime().getTime()) / (1000 * 60 * 60 * 24));
    }
}

第二种：

public class Demo {
public static void main(String[] args) throws ParseException {
String s1="2016-1-2";
String s2="2016-1-1";
DateFormat df=new SimpleDateFormat("yyyy-MM-dd");
Calendar calendar=new GregorianCalendar();
Date d1=df.parse(s1);
Date d2=df.parse(s2);
System.out.println((d1.getTime()-d2.getTime())/(60*60*1000*24));

}

}