时间工具类DataUtils.java，通过输入开始时间和截至时间，获取之间的日期

在进行数据统计时，常常需要通过接收2个参数，起始时间和结束时间，获取2个时间之间的日期。

例如：输入参数：2019-04-01，2019-04-10

需要获取2个时间之间的日期：即：[2019-04-01,2019-04-02,2019-04-03,2019-04-04,2019-04-05,2019-04-06,2019-04-07,2019-04-08,2019-04-09,2019-04-10]

本例子采用多种时间格式：分别为：日期、月份、季度、年份等4种维度。

详情如下:

package com.casic.ht304.cdgl.utils;

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

/**
 * @author fanyanyan
 * @Title: DateUtils
 * @ProjectName testProject
 * @date 2019/4/23 15:16
 */
public class DateUtils {
    /**
     * 获取两个日期之间的日期，2019-04-01，2019-04-10
     *
     * @param startTime
     * @param endTime
     * @return 日期的List<String>集合
     */
    public List<Object> getBetweenDate(String startTime, String endTime) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

        // 声明保存日期集合
        List<Object> list = new ArrayList<>();
        try {
            // 转化成日期类型
            Date startDate = sdf.parse(startTime);
            Date endDate = sdf.parse(endTime);
            //用Calendar 进行日期比较判断
            Calendar calendar = Calendar.getInstance();
            while (startDate.getTime() <= endDate.getTime()) {
                // 把日期添加到集合
                list.add(sdf.format(startDate));
                // 设置日期
                calendar.setTime(startDate);
                //把日期增加一天
                calendar.add(Calendar.DATE, 1);
                // 获取增加后的日期
                startDate = calendar.getTime();
            }
        } catch (ParseException e) {
            e.printStackTrace();
        }

        return list;
    }

    /**
     * 获取两个月份日期之间的月份：2019-01，2019-04
     *
     * @param startTime
     * @param endTime
     * @return 月份日期的List<String>集合
     */
    public List<Object> getBetweenMonth(String startTime, String endTime) {
        List list = new ArrayList<Object>();
        String[] timeStart = startTime.split("-");
        String[] timeEnd = endTime.split("-");
        int yearStart = Integer.parseInt(timeStart[0]);
        int firstYear = yearStart;
        int yearEnd = Integer.parseInt(timeEnd[0]);
        int monthStart = Integer.parseInt(timeStart[1]);
        int firstMonth = yearStart;
        int monthEnd = Integer.parseInt(timeEnd[1]);
        while (yearStart <= yearEnd) {
            if (yearStart < yearEnd) {
                int i = monthStart;
                if (yearStart != firstYear){
                    i=1;
                }
                while (i <= 12) {
                    String date = "";
                    if ((i + "").length() == 1) {
                        date = yearStart + "" + "-0" + i + "";
                    } else {
                        date = yearStart + "" + "-" + i + "";
                    }
                    list.add(date);
                    i++;
                }
            }
            if (yearStart == yearEnd) {
                int i = 1;
                if (yearStart == firstYear){
                    i=monthStart;
                }
                while (i <= monthEnd) {
                    String date = "";
                    if ((i + "").length() == 1) {
                        date = yearStart + "" + "-0" + i + "";
                    } else {
                        date = yearStart + "" + "-" + i + "";
                    }
                    list.add(date);
                    i++;
                }
            }
            yearStart++;
        }
        return list;
    }

    /**
     * 获取两个年之间的所有的季度：2018，2019
     *
     * @param startTime
     * @param endTime
     * @return 季度日期的List<String>集合：[2018-1,2018-2,...,2019-3,2019-4]
     */
    public List<Object> getBetweenQuarter(String startTime, String endTime) {
        List list = new ArrayList<Object>();
        int yearStart = Integer.parseInt(startTime);
        int yearEnd = Integer.parseInt(endTime);
        while (yearStart <= yearEnd) {
            for (int i = 1; i <= 4; i++) {
                list.add(yearStart + "-" + i);
            }
            yearStart++;
        }

        return list;
    }

    /**
     * 获取两个年份之间的所有年份
     *
     * @param startTime
     * @param endTime
     * @return 返回年份List<String>:[2018,2019]
     */
    public List<Object> getBetweenYear(String startTime, String endTime) {
        List list = new ArrayList<>();
        int yearStart = Integer.parseInt(startTime);
        int yearEnd = Integer.parseInt(endTime);
        while (yearStart <= yearEnd) {
            list.add(yearStart);
            yearStart++;
        }
        return list;
    }

    public static void main(String[] args) {
        DateUtils du = new DateUtils();
//        System.out.println(du.getBetweenYear("2018", "2019"));
//        System.out.println(du.getBetweenQuarter("2018", "2019"));
        System.out.println(du.getBetweenMonth("2018-01", "2018-02"));
//        System.out.println(du.getBetweenDate("2019-04-01", "2019-04-22"));
    }
}