获取某一时间段特定星期几的日期

package cn.com.utils;

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


/**
 * 获取某一时间段特定星期几的日期
 * @author 
 *
 */
public class WeekDayUtil {
    public static void main(String[] args) throws java.text.ParseException {
        getDates("2018-05-27", "2018-06-11","Saturday|Sunday");
    }

    /**
     * 获取某一时间段特定星期几的日期
     * @param dateFrom 开始时间
     * @param dateEnd 结束时间
     * @param weekDays 星期
     * @return 返回时间数组
     * @throws java.text.ParseException 
     */
    public static String[] getDates(String dateFrom, String dateEnd, String weekDays) throws java.text.ParseException {
        long time = 1l;
        long perDayMilSec = 24 * 60 * 60 * 1000;
        List<String> dateList = new ArrayList<String>();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        //需要查询的星期系数
        String strWeekNumber = weekForNum(weekDays);
        try {
            dateFrom = sdf.format(sdf.parse(dateFrom).getTime() - perDayMilSec);
            while (true) {
                    time = sdf.parse(dateFrom).getTime();
                    time = time + perDayMilSec;
                    Date date = new Date(time);
                    dateFrom = sdf.format(date);
                    if (dateFrom.compareTo(dateEnd) <= 0) {
                        //查询的某一时间的星期系数
                        Integer weekDay = dayForWeek(date);                    
                        //判断当期日期的星期系数是否是需要查询的
                        if (strWeekNumber.indexOf(weekDay.toString())!=-1) {
                            System.out.println(dateFrom);
                            dateList.add(dateFrom);
                        }
                    } else {
                        break;
                    }
            }
        } catch (ParseException e1) {
            e1.printStackTrace();
        }
        String[] dateArray = new String[dateList.size()];
        dateList.toArray(dateArray);
        return dateArray;
    }

    //等到当期时间的周系数。Sunday：1，Monday：2，Tuesday：3，Wednesday：4，Thursday：5，Friday：6，Saturday：7
    public static Integer dayForWeek(Date date) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        return calendar.get(Calendar.DAY_OF_WEEK);
    }
    
    /**
     * 得到对应星期的系数  Sunday：1，Monday：2，Tuesday：3，Wednesday：4，Thursday：5，Friday：6，Saturday：7
     * @param weekDays 星期格式  Monday|Tuesday
     */
    public static String weekForNum(String weekDays){
        //返回结果为组合的星期系数
        String weekNumber = "";
        //解析传入的星期
        if(weekDays.indexOf("|")!=-1){//多个星期数
            String []strWeeks = weekDays.split("\\|");
            for(int i=0;i<strWeeks.length;i++){
                weekNumber = weekNumber + "" + getWeekNum(strWeeks[i]).toString();
            }
        }else{//一个星期数
            weekNumber = getWeekNum(weekDays).toString();
        }
        
        return weekNumber;
        
    }
    
    //将星期转换为对应的系数  Sunday：1，Monday：2，Tuesday：3，Wednesday：4，Thursday：5，Friday：6，Saturday：7
    public static Integer getWeekNum(String strWeek){
        Integer number = 1;//默认为Sunday
        if("Sunday".equals(strWeek)){
            number = 1;
        }else if("Monday".equals(strWeek)){
            number = 2;
        }else if("Tuesday".equals(strWeek)){
            number = 3;
        }else if("Wednesday".equals(strWeek)){
            number = 4;
        }else if("Thursday".equals(strWeek)){
            number = 5;
        }else if("Friday".equals(strWeek)){
            number = 6;
        }else if("Saturday".equals(strWeek)){
            number = 7;
        }
        return number;
    }

}

package cn.com.utils;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;

/**
 * 获取时间段内所有日期
 *
 */
public class FindDates {

    public static void main(String[] args) throws Exception {

        Calendar cal = Calendar.getInstance();
        String start = "2018-05-25";
        String end = "2018-06-30";
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date dBegin = sdf.parse(start);
        Date dEnd = sdf.parse(end);
        List<Date> lDate = findDates(dBegin, dEnd);
        for (Date date : lDate) {
            System.out.println(sdf.format(date));
        }
    }

    public static List<Date> findDates(Date dBegin, Date dEnd) {
        List lDate = new ArrayList();
        lDate.add(dBegin);
        Calendar calBegin = Calendar.getInstance();
        // 使用给定的 Date 设置此 Calendar 的时间
        calBegin.setTime(dBegin);
        Calendar calEnd = Calendar.getInstance();
        // 使用给定的 Date 设置此 Calendar 的时间
        calEnd.setTime(dEnd);
        // 测试此日期是否在指定日期之后
        while (dEnd.after(calBegin.getTime())) {
            // 根据日历的规则，为给定的日历字段添加或减去指定的时间量
            calBegin.add(Calendar.DAY_OF_MONTH, 1);
            lDate.add(calBegin.getTime());
        }
        return lDate;
    }
}