Java 计算两个日期相差多少天

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;

public class Tests_1 {
    public static void main(String[] args) throws ParseException {
        System.out.println(daysBetween("20210526","20220103"));
    }
    public static int daysBetween(String startdate,String enddate) throws ParseException {
        SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMdd");
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(sdf.parse(startdate));
        long start = calendar.getTimeInMillis();
        calendar.setTime(sdf.parse(enddate));
        long end = calendar.getTimeInMillis();
        long betweendays=(end-start)/(1000*3600*24);
        int days = Integer.parseInt(String.valueOf(betweendays));
        return days;
    }
}

输出结果：222

备注：如不抛出异常，可以用 try/catch。