获取当前时间所在凌晨和23:59:59

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

public class DateUtil {
/**
* 凌晨
* @param date
* @flag 0 返回yyyy-MM-dd 00:00:00日期<br>
*       1 返回yyyy-MM-dd 23:59:59日期
* @return
*/
public static Date weeHours(Date date, int flag) {
Calendar cal = Calendar.getInstance();
cal.setTime(date);
int hour = cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
//时分秒（毫秒数）
long millisecond = hour*60*60*1000 + minute*60*1000 + second*1000;
//凌晨00:00:00
cal.setTimeInMillis(cal.getTimeInMillis()-millisecond);

if (flag == 0) {
return cal.getTime();
} else if (flag == 1) {
//凌晨23:59:59
cal.setTimeInMillis(cal.getTimeInMillis()+23*60*60*1000 + 59*60*1000 + 59*1000);
}
return cal.getTime();
}

public static void main(String[] args) {
System.out.println(weeHours(new Date(), 0));
System.out.println(weeHours(new Date(), 1));
}
}