日期工具类

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;

public class DateUtil {

    //时间格式
    public static final String PATTERN_YYYYMMDDHH = "yyyyMMddHH";
    public static final String PATTERN_YYYY_MM_DDHHMM = "yyyy-MM-dd HH:mm";

    /***
     * 从yyyy-MM-dd HH:mm格式转成yyyyMMddHH格式
     * @param dateStr
     * @return
     */
    public static String formatStr(String dateStr,String opattern,String npattern){
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat(opattern);
        try {
            Date date = simpleDateFormat.parse(dateStr);
            simpleDateFormat = new SimpleDateFormat(npattern);
            return simpleDateFormat.format(date);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }

    /***
     * 获取指定日期的凌晨
     * @return
     */
    public static Date toDayStartHour(Date date){
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 0);
        Date start = calendar.getTime();
        return start;
    }


    /***
     * 时间增加N分钟
     * @param date
     * @param minutes
     * @return
     */
    public static Date addDateMinutes(Date date,int minutes){
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.MINUTE, minutes);// 24小时制
        date = calendar.getTime();
        return date;
    }

    /***
     * 时间递增N小时
     * @param hour
     * @return
     */
    public static Date addDateHour(Date date,int hour){
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.HOUR, hour);// 24小时制
        date = calendar.getTime();
        return date;
    }

    /***
     * 获取时间菜单
     * @return
     */
    public static List<Date> getDateMenus(){
        //定义一个List<Date>集合，存储所有时间段
        List<Date> dates = getDates(12);
        //判断当前时间属于哪个时间范围
        Date now = new Date();
        for (Date cdate : dates) {
            //开始时间<=当前时间<开始时间+2小时
            if(cdate.getTime()<=now.getTime() && now.getTime()<addDateHour(cdate,2).getTime()){
                now = cdate;
                break;
            }
        }

        //当前需要显示的时间菜单
        List<Date> dateMenus = new ArrayList<Date>();
        for (int i = 0; i <5 ; i++) {
            dateMenus.add(addDateHour(now,i*2));
        }
        return dateMenus;
    }

    /***
     * 指定时间往后N个时间间隔
     * @param hours
     * @return
     */
    public static List<Date> getDates(int hours) {
        List<Date> dates = new ArrayList<Date>();
        //循环12次
        Date date = toDayStartHour(new Date()); //凌晨
        for (int i = 0; i <hours ; i++) {
            //每次递增2小时,将每次递增的时间存入到List<Date>集合中
            dates.add(addDateHour(date,i*2));
        }
        return dates;
    }

    /***
     * 时间转成yyyyMMddHH
     * @param date
     * @param pattern
     * @return
     */
    public static String data2str(Date date, String pattern){
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat(pattern);
        return simpleDateFormat.format(date);
    }

    public static void main(String[] args) {
        //返回时间菜单列表
        List<Date> dateMenus = getDateMenus();
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHH");
        for (Date dateMenu : dateMenus) {
            System.out.println(format.format(dateMenu));
        }
    }
}