Date-时间工具类

我就是我 2022-11-30 15:51 226阅读 0赞

**问题引出：**  
我们每次用到Date时间这个类的时候，时间对象转化为指定的字符串，或者把字符串转化为时间对象，等等相对来说会比较麻烦，下面这个时间工具类提供了各种转化方法，调用相应方法就能得到你想要的答案

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**代码**

public class DateUtils {
        /**
         * 日期转换-  String -> Date
         *
         * @param dateString 字符串时间
         * @return Date类型信息
         * @throws Exception 抛出异常
         */
        public static Date parseString2Date(String dateString) throws ParseException {
            if (dateString == null) {
                return null;
            }
            return parseString2Date(dateString, "yyyy-MM-dd");
        }
    
        /**
         * 日期转换-  String -> Date
         *
         * @param dateString 字符串时间
         * @param pattern    格式模板
         * @return Date类型信息
         * @throws Exception 抛出异常
         */
        public static Date parseString2Date(String dateString, String pattern) throws ParseException {
            if (dateString == null) {
                return null;
            }
            SimpleDateFormat sdf = new SimpleDateFormat(pattern);
            Date date = sdf.parse(dateString);
            return date;
        }
    
        /**
         * 日期转换 Date -> String
         * @param date Date类型信息
         * @return 字符串时间
         * @throws Exception 抛出异常
         */
        public static String parseDate2String(Date date) {
            if (date == null) {
                return null;
            }
            return parseDate2String(date, "yyyy-MM-dd HH:mm:ss");
        }
    
        /**
         * 日期转换 Date -> String
         *
         * @param date    Date类型信息
         * @param pattern 格式模板
         * @return 字符串时间
         * @throws Exception 抛出异常
         */
        public static String parseDate2String(Date date, String pattern){
            if (date == null) {
                return null;
            }
            SimpleDateFormat sdf = new SimpleDateFormat(pattern);
            String strDate = sdf.format(date);
            return strDate;
        }
    
        /**
         * 获取当前日期的本周一是几号
         *
         * @return 本周一的日期
         */
        public static Date getThisWeekMonday() {
            Calendar cal = Calendar.getInstance();
            cal.setTime(new Date());
            // 获得当前日期是一个星期的第几天
            int dayWeek = cal.get(Calendar.DAY_OF_WEEK);
            if (1 == dayWeek) {
                cal.add(Calendar.DAY_OF_MONTH, -1);
            }
            // 设置一个星期的第一天，按中国的习惯一个星期的第一天是星期一
            cal.setFirstDayOfWeek(Calendar.MONDAY);
            // 获得当前日期是一个星期的第几天
            int day = cal.get(Calendar.DAY_OF_WEEK);
            // 根据日历的规则，给当前日期减去星期几与一个星期第一天的差值
            cal.add(Calendar.DATE, cal.getFirstDayOfWeek() - day);
            return cal.getTime();
        }
    
        /**
         * 获取当前日期周的最后一天
         *
         * @return 当前日期周的最后一天
         */
        public static Date getSundayOfThisWeek() {
            Calendar c = Calendar.getInstance();
            int dayOfWeek = c.get(Calendar.DAY_OF_WEEK) - 1;
            if (dayOfWeek == 0) {
                dayOfWeek = 7;
            }
            c.add(Calendar.DATE, -dayOfWeek + 7);
            return c.getTime();
        }
    
        /**
         * 根据日期区间获取月份列表
         *
         * @param minDate 开始时间
         * @param maxDate 结束时间
         * @return 月份列表
         * @throws Exception
         */
        public static List<String> getMonthBetween(String minDate, String maxDate, String format) throws ParseException{
            ArrayList<String> result = new ArrayList<String>();
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");
    
            Calendar min = Calendar.getInstance();
            Calendar max = Calendar.getInstance();
    
            min.setTime(sdf.parse(minDate));
            min.set(min.get(Calendar.YEAR), min.get(Calendar.MONTH), 1);
    
            max.setTime(sdf.parse(maxDate));
            max.set(max.get(Calendar.YEAR), max.get(Calendar.MONTH), 2);
            SimpleDateFormat sdf2 = new SimpleDateFormat(format);
    
            Calendar curr = min;
            while (curr.before(max)) {
                result.add(sdf2.format(curr.getTime()));
                curr.add(Calendar.MONTH, 1);
            }
    
            return result;
        }
    
        /**
         * 根据日期获取年度中的周索引
         *
         * @param date 日期
         * @return 周索引
         * @throws Exception
         */
        public static Integer getWeekOfYear(String date) throws ParseException {
            Date useDate = parseString2Date(date);
            Calendar cal = Calendar.getInstance();
            cal.setTime(useDate);
            return cal.get(Calendar.WEEK_OF_YEAR);
        }
    
        /**
         * 根据年份获取年中周列表
         *
         * @param year 年分
         * @return 周列表
         * @throws Exception
         */
        public static Map<Integer, String> getWeeksOfYear(String year) throws ParseException {
            Date useDate = parseString2Date(year, "yyyy");
            Calendar cal = Calendar.getInstance();
            cal.setTime(useDate);
            //获取年中周数量
            int weeksCount = cal.getWeeksInWeekYear();
            Map<Integer, String> mapWeeks = new HashMap<>(55);
            for (int i = 0; i < weeksCount; i++) {
                cal.get(Calendar.DAY_OF_YEAR);
                mapWeeks.put(i + 1, parseDate2String(getFirstDayOfWeek(cal.get(Calendar.YEAR), i)));
            }
            return mapWeeks;
        }
    
        /**
         * 获取某年的第几周的开始日期
         *
         * @param year 年分
         * @param week 周索引
         * @return 开始日期
         * @throws Exception
         */
        public static Date getFirstDayOfWeek(int year, int week) {
            Calendar c = new GregorianCalendar();
            c.set(Calendar.YEAR, year);
            c.set(Calendar.MONTH, Calendar.JANUARY);
            c.set(Calendar.DATE, 1);
    
            Calendar cal = (GregorianCalendar) c.clone();
            cal.add(Calendar.DATE, week * 7);
    
            return getFirstDayOfWeek(cal.getTime());
        }
    
        /**
         * 获取某年的第几周的结束日期
         *
         * @param year 年份
         * @param week 周索引
         * @return 结束日期
         * @throws Exception
         */
        public static Date getLastDayOfWeek(int year, int week)  {
            Calendar c = new GregorianCalendar();
            c.set(Calendar.YEAR, year);
            c.set(Calendar.MONTH, Calendar.JANUARY);
            c.set(Calendar.DATE, 1);
    
            Calendar cal = (GregorianCalendar) c.clone();
            cal.add(Calendar.DATE, week * 7);
    
            return getLastDayOfWeek(cal.getTime());
        }
    
        /**
         * 获取当前时间所在周的开始日期
         *
         * @param date 当前时间
         * @return 开始时间
         */
        public static Date getFirstDayOfWeek(Date date) {
            Calendar c = new GregorianCalendar();
            c.setFirstDayOfWeek(Calendar.SUNDAY);
            c.setTime(date);
            c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek());
            return c.getTime();
        }
    
        /**
         * 获取当前时间所在周的结束日期
         *
         * @param date 当前时间
         * @return 结束日期
         */
        public static Date getLastDayOfWeek(Date date) {
            Calendar c = new GregorianCalendar();
            c.setFirstDayOfWeek(Calendar.SUNDAY);
            c.setTime(date);
            c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6);
            return c.getTime();
        }
        //获得上周一的日期
        public static Date geLastWeekMonday(Date date) {
            Calendar cal = Calendar.getInstance();
            cal.setTime(getThisWeekMonday(date));
            cal.add(Calendar.DATE, -7);
            return cal.getTime();
        }
    
        //获得本周一的日期
        public static Date getThisWeekMonday(Date date) {
            Calendar cal = Calendar.getInstance();
            cal.setTime(date);
            // 获得当前日期是一个星期的第几天
            int dayWeek = cal.get(Calendar.DAY_OF_WEEK);
            if (1 == dayWeek) {
                cal.add(Calendar.DAY_OF_MONTH, -1);
            }
            // 设置一个星期的第一天，按中国的习惯一个星期的第一天是星期一
            cal.setFirstDayOfWeek(Calendar.MONDAY);
            // 获得当前日期是一个星期的第几天
            int day = cal.get(Calendar.DAY_OF_WEEK);
            // 根据日历的规则，给当前日期减去星期几与一个星期第一天的差值
            cal.add(Calendar.DATE, cal.getFirstDayOfWeek() - day);
            return cal.getTime();
        }
    
        //获得下周一的日期
        public static Date getNextWeekMonday(Date date) {
            Calendar cal = Calendar.getInstance();
            cal.setTime(getThisWeekMonday(date));
            cal.add(Calendar.DATE, 7);
            return cal.getTime();
        }
    
        //获得今天日期
        public static Date getToday(){
            return new Date();
        }
    
        //获得本月一日的日期
        public static Date getFirstDay4ThisMonth(){
            Calendar calendar = Calendar.getInstance();
            calendar.set(Calendar.DAY_OF_MONTH,1);
            return calendar.getTime();
        }
    
        public static void main(String[] args) {
            try {
                System.out.println("本周一" + parseDate2String(getThisWeekMonday()));
                System.out.println("本月一日" + parseDate2String(getFirstDay4ThisMonth()));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }