java8.0日期工具类

柔光的暖阳◎ 2021-12-18 18:43 242阅读 0赞

针对java8.0获取当月的第一天、最后一天、当周的第一天和最后一天、或者指定日期的所在周的最后一天活第一天，指定日期所在月份的第一天和最后一天。

package com.lghszz.todo.service.utils;
    
    import java.time.*;
    import java.time.format.DateTimeFormatter;
    import java.time.temporal.TemporalAdjusters;
    import java.util.Date;
    
    /**
     * @author lgh 2019-06-30
     * @version 1.0
     * Description: 时间转换器
     */
    public class DateUtils {
    
        private DateUtils() {
            throw new IllegalStateException("工具类不能实例化！！！");
        }
    
        static DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        static DateTimeFormatter formatter2 = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    
        /**
         * 格式化指定时间
         */
        public static String formatAnyTime(Date date) {
            return formatter2.format(toLocalDateTime(date));
        }
    
        /**
         * 获取本月第一天
         */
        public static String getDateByMonthFirst() {
            return LocalDate.now().with(TemporalAdjusters.firstDayOfMonth()).toString();
        }
    
        /**
         * 获取当年第一天
         */
        public static String getDateByYearFirst() {
            return LocalDate.now().with(TemporalAdjusters.firstDayOfYear()).toString();
        }
    
        /**
         * 获取当周第一天
         */
        public static String getDateByWeekFirst() {
            return LocalDate.now().minusWeeks(0).with(DayOfWeek.MONDAY).toString();
        }
    
        /**
         * 获取指定月份月第一天
         *
         * @param time yyyy-MM-dd
         */
        public static String getAnyDateByMonthFirst(String time) {
            LocalDate localDate = toLocalDate(time);
            return localDate.with(TemporalAdjusters.firstDayOfMonth()).toString();
        }
    
        /**
         * 获取指定年年第一天
         *
         * @param time yyyy-MM-dd
         */
        public static String getAnyDateByYearFirst(String time) {
            LocalDate localDate = toLocalDate(time);
            return localDate.with(TemporalAdjusters.firstDayOfYear()).toString();
        }
    
        /**
         * 获取指定周第一天
         *
         * @param time yyyy-MM-dd
         */
        public static String getAnyDateByWeekFirst(String time) {
            LocalDate localDate = toLocalDate(time);
            return localDate.minusWeeks(0).with(DayOfWeek.MONDAY).toString();
        }
    
        public static void main(String[] args) {
            for (int i=0; i<6;i++){
                System.out.println(getDateByTopMonth(i));
                System.out.println(getDateByTopWeek(i));
            }
        }
    
        /**
         * 字符串类型转换成 LocalDate
         */
        private static LocalDate toLocalDate(String time) {
            return LocalDate.parse(time, formatter2);
        }
    
        private static LocalDateTime toLocalDateTime(Date date) {
            Instant instant = date.toInstant();
            ZoneId zone = ZoneId.systemDefault();
            return LocalDateTime.ofInstant(instant, zone);
        }
    
    
        /**
         * 获取指定日期的上几个月 最后一天
         */
        public static String getDateByTopMonth(String time, long count) {
            LocalDate localDate = toLocalDate(time);
            return     localDate.minusMonths(count).with(TemporalAdjusters.lastDayOfMonth()).toString();
        }
    
        /**
         * 获取指定日期的上几周 星期日
         */
        public static String getDateByTopWeek(String time, long count) {
            LocalDate localDate = toLocalDate(time);
            return localDate.minusWeeks(count).with(DayOfWeek.SUNDAY).toString();
        }
    
    
        /**
         * 获取上几个月 最后一天
         */
        public static String getDateByTopMonth(long count) {
            return LocalDate.now().minusMonths(count).with(TemporalAdjusters.lastDayOfMonth()).toString();
        }
    
        /**
         * 获取上几周 星期日
         */
        public static String getDateByTopWeek(long count) {
            return LocalDate.now().minusWeeks(count).with(DayOfWeek.SUNDAY).toString();
        }
    
    }

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