java 获取两个日期天数

可以使用Java中的Date类和Calendar类来获取两个日期之间的天数。具体实现方法如下：

import java.util.Calendar;
import java.util.Date;

public class DateUtil {
    /**
     * 获取两个日期之间的天数
     * @param startDate 开始日期
     * @param endDate 结束日期
     * @return 两个日期之间的天数
     */
    public static int getDaysBetween(Date startDate, Date endDate) {
        Calendar startCalendar = Calendar.getInstance();
        startCalendar.setTime(startDate);
        Calendar endCalendar = Calendar.getInstance();
        endCalendar.setTime(endDate);
        //确保startCalendar在endCalendar之前
        if (startCalendar.after(endCalendar)) {
            Calendar temp = startCalendar;
            startCalendar = endCalendar;
            endCalendar = temp;
        }
        int days = endCalendar.get(Calendar.DAY_OF_YEAR) - startCalendar.get(Calendar.DAY_OF_YEAR);
        int endYear = endCalendar.get(Calendar.YEAR);
        if (startCalendar.get(Calendar.YEAR) != endYear) {
            startCalendar = (Calendar) startCalendar.clone();
            do {
                days += startCalendar.getActualMaximum(Calendar.DAY_OF_YEAR);
                startCalendar.add(Calendar.YEAR, 1);
            } while (startCalendar.get(Calendar.YEAR) != endYear);
        }
        return days;
    }
}