DateUtil 工具类，基于JDK8+

package com.xx.dubbo.dubboservice.utils;

import java.time.*;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAdjusters;
import java.time.temporal.WeekFields;
import java.util.Date;
import java.util.Locale;


public class DateUtil {

    //数据库格式的日期
    public static final String SQL_MonTH = "yyyy-MM";
    public static final String SQL_DATE = "yyyy-MM-dd";
    public static final String SQL_TIME = "yyyy-MM-dd HH:mm:ss";
    public static final String SQL_TIMESTAMP = "yyyy-MM-dd HH:mm:ss.SS";

    //斜杠格式的日期
    public static final String DATE = "yyyy/MM/dd";
    public static final String TIMESTAMP = "yyyy/MM/dd HH:mm:ss.SS";
    public static final String TIMESTAMP_SHORT = "yyyy/MM/dd HH:mm";
    public static final String TIME = "HH:mm:ss";
    public static final String TIME_SHORT = "HH:mm";

    //不常用日期格式
    public static final String CHINESEDATE = "yyyy年MM月dd日";
    public static final String DATE_TIME = "yyyyMMddHHmmss";
    public static final String DATE_TIME_DETAIL = "yyyyMMddHHmmssSS";
    public static final String DATE_DAY = "yyyyMMdd";
    public static final String DATE_HOUR = "yyyyMMddHH";


    
    private DateUtil(){

    }

    
    public static LocalDateTime dateToLocalDateTime(Date date){
        Instant instant = date.toInstant();
        return instant.atZone(ZoneId.systemDefault()).toLocalDateTime();
    }

    
    public static Date localDateTimeToDate(LocalDateTime localDateTime){
        ZonedDateTime zdt = localDateTime.atZone(ZoneId.systemDefault());
        return Date.from(zdt.toInstant());
    }

    
    public static String dateTimeToStr(LocalDateTime localDateTime, String pattern) {
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
        return localDateTime.format(formatter);
    }

    
    public static LocalDateTime strToLocalDateTime(String dateTimeStr, String pattern) {
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
        return LocalDateTime.parse(dateTimeStr, formatter);
    }

    
    public static LocalDateTime getStartDateTimeWithHMS(LocalDateTime localDateTime) {
        return LocalDateTime.of(localDateTime.toLocalDate(), LocalTime.MIN);
    }

    
    public static LocalDateTime getEndDateWithHMS(LocalDateTime localDateTime){
        return LocalDateTime.of(localDateTime.toLocalDate(), LocalTime.MAX);
    }



    public static LocalDateTime getAfterYears(LocalDateTime localDateTime, int count){
        return localDateTime.plusYears(count);
    }

    public static LocalDateTime getAfterMonths(LocalDateTime localDateTime, int count){
        return localDateTime.plusMonths(count);
    }

    public static LocalDateTime getAfterDays(LocalDateTime localDateTime, int count){
        return localDateTime.plusDays(count);
    }

    public static LocalDateTime getAfterMinutes(LocalDateTime localDateTime, int count){
        return localDateTime.plusMinutes(count);
    }

    public static LocalDateTime getAfterSeconds(LocalDateTime localDateTime, int count){
        return localDateTime.plusSeconds(count);
    }



    
    public static LocalDateTime getYearFirstDay(LocalDateTime localDateTime) {
        return localDateTime.with(TemporalAdjusters.firstDayOfYear());
    }

    
    public static LocalDateTime getYearLastDay(LocalDateTime localDateTime) {
        return localDateTime.with(TemporalAdjusters.lastDayOfYear());
    }


    
    public static LocalDateTime getMonthFirstDay(LocalDateTime localDateTime) {
        return localDateTime.with(TemporalAdjusters.firstDayOfMonth());
    }

    
    public static LocalDateTime getMonthLastDay(LocalDateTime localDateTime) {
        return localDateTime.with(TemporalAdjusters.lastDayOfMonth());
    }


    
    public static LocalDateTime getWeekFirstDay(LocalDateTime localDateTime, Locale locale) {
        return localDateTime.with(WeekFields.of(locale==null?Locale.CHINA:locale).dayOfWeek(),1);
    }

    
    public static LocalDateTime getWeekLastDay(LocalDateTime localDateTime, Locale locale) {
        return localDateTime.with(WeekFields.of(locale==null?Locale.CHINA:locale).dayOfWeek(),7);
    }



    
    public static int getYearDiff(LocalDateTime smallDateTime, LocalDateTime bigDateTime) {
        return (int)smallDateTime.until(bigDateTime, ChronoUnit.YEARS);
    }

    
    public static int getMonthDiff(LocalDateTime smallDateTime, LocalDateTime bigDateTime) {
        return (int)smallDateTime.until(bigDateTime, ChronoUnit.MONTHS);
    }

    
    public static int getDayDiff(LocalDateTime smallDateTime, LocalDateTime bigDateTime){
        return (int)smallDateTime.until(bigDateTime, ChronoUnit.DAYS);
    }

    
    public static int getHourDiff(LocalDateTime smallDateTime, LocalDateTime bigDateTime){
        return (int)smallDateTime.until(bigDateTime, ChronoUnit.HOURS);
    }

    
    public static int getMinutesDiff(LocalDateTime smallDateTime, LocalDateTime bigDateTime){
        return (int)smallDateTime.until(bigDateTime, ChronoUnit.MINUTES);
    }

    
    public static int getSecondsDiff(LocalDateTime smallDateTime, LocalDateTime bigDateTime){
        return (int)smallDateTime.until(bigDateTime, ChronoUnit.SECONDS);
    }


    public static void main(String[] args) {
        LocalDateTime now = LocalDateTime.now();
        System.out.println(getAfterMonths(now, 1));
    }

}

转载：https://www.cnblogs.com/xieyanke/p/12836268.html