Java 日期计算工具类(日期比较，类型转换，日期加减计算，首尾日期获取)

package com.igrs.met.utils;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import org.apache.commons.lang3.StringUtils;
import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;

public class DateUtils {
    private static final String STANDARD_FORMAT = "yyyy-MM-dd HH:mm:ss";

    /**
     * 日期比较
     * @return true: t1 > t2
     */
    public static boolean compare(Date t1 , Date t2 , String formatPattern) {
        String format1 = dateToStr(t1);
        String format2 = dateToStr(t2);
        DateTimeFormatter formatter = DateTimeFormat.forPattern(formatPattern);
        DateTime season1 = DateTime.parse(format1 , formatter);
        DateTime season2 = DateTime.parse(format2 , formatter);
        return season1.isAfter(season2);
    }

    /**
     * date类型 -> string类型
     *
     * @param date
     * @return
     */
    public static String dateToStr(Date date) {
        if (date == null) return StringUtils.EMPTY;
        DateTime dateTime = new DateTime(date);
        return dateTime.toString(STANDARD_FORMAT);
    }

    /**
     * date类型 -> string类型
     *
     * @param date
     * @param formatPattern
     * @return
     */
    public static String dateToStr(Date date, String formatPattern) {
        if (date == null) return StringUtils.EMPTY;
        DateTime dateTime = new DateTime(date);
        return dateTime.toString(formatPattern);
    }

    /**
     * string类型 -> date类型
     *
     * @param timeStr
     * @return
     */
    public static Date strToDate(String timeStr) {
        DateTimeFormatter dateTimeFormatter = DateTimeFormat.forPattern(STANDARD_FORMAT);
        DateTime dateTime = dateTimeFormatter.parseDateTime(timeStr);
        return dateTime.toDate();
    }

    /**
     * 判断date日期是否过期(与当前时刻比较)
     *
     * @param date
     * @return
     */
    public static boolean isTimeExpired(Date date) {
        if (null == date) return true;
        String timeStr = dateToStr(date);
        return isBeforeNow(timeStr);
    }

    /**
     * 判断date日期是否过期(与当前时刻比较)
     *
     * @param timeStr
     * @return
     */
    public static boolean isTimeExpired(String timeStr) {
        if (StringUtils.isBlank(timeStr)) return true;
        return isBeforeNow(timeStr);
    }

    /**
     * 判断timeStr是否在当前时刻之前
     *
     * @param timeStr
     * @return
     */
    private static boolean isBeforeNow(String timeStr) {
        DateTimeFormatter format = DateTimeFormat.forPattern(STANDARD_FORMAT);
        DateTime dateTime = DateTime.parse(timeStr, format);
        return dateTime.isBeforeNow();
    }

    /**
     * 日期加天数
     *
     * @param date
     * @param days
     * @return
     */
    public static Date plusDays(Date date, Integer days) {
        return plusOrMinusDays(date, days, 0);
    }

    /**
     * 日期减天数
     *
     * @param date
     * @param days
     * @return
     */
    public static Date minusDays(Date date, Integer days) {
        return plusOrMinusDays(date, days, 1);
    }

    /**
     * 加减天数
     *
     * @param date
     * @param days
     * @param type 0:加天数 1:减天数
     * @return
     */
    private static Date plusOrMinusDays(Date date, Integer days, Integer type) {
        if (null == date) return null;
        days = null == days ? 0 : days;

        DateTime dateTime = new DateTime(date);
        if (type == 0) {
            dateTime = dateTime.plusDays(days);
        } else {
            dateTime = dateTime.minusDays(days);
        }

        return dateTime.toDate();
    }

    /**
     * 日期加分钟
     *
     * @param date
     * @param minutes
     * @return
     */
    public static Date plusMinutes(Date date, Integer minutes) {
        return plusOrMinusMinutes(date, minutes, 0);
    }

    /**
     * 日期减分钟
     *
     * @param date
     * @param minutes
     * @return
     */
    public static Date minusMinutes(Date date, Integer minutes) {
        return plusOrMinusMinutes(date, minutes, 1);
    }

    /**
     * 加减分钟
     *
     * @param date
     * @param minutes
     * @param type    0:加分钟 1:减分钟
     * @return
     */
    private static Date plusOrMinusMinutes(Date date, Integer minutes, Integer type) {
        if (null == date) return null;
        minutes = null == minutes ? 0 : minutes;

        DateTime dateTime = new DateTime(date);
        if (type == 0) {
            dateTime = dateTime.plusMinutes(minutes);
        } else {
            dateTime = dateTime.minusMinutes(minutes);
        }

        return dateTime.toDate();
    }

    /**
     * 日期加月份
     *
     * @param date
     * @param months
     * @return
     */
    public static Date plusMonths(Date date, Integer months) {
        return plusOrMinusMonths(date, months, 0);
    }

    /**
     * 日期减月份
     *
     * @param date
     * @param months
     * @return
     */
    public static Date minusMonths(Date date, Integer months) {
        return plusOrMinusMonths(date, months, 1);
    }

    /**
     * 加减月份
     *
     * @param date
     * @param months
     * @param type   0:加月份 1:减月份
     * @return
     */
    private static Date plusOrMinusMonths(Date date, Integer months, Integer type) {
        if (null == date) return null;
        months = null == months ? 0 : months;

        DateTime dateTime = new DateTime(date);
        if (type == 0) {
            dateTime = dateTime.plusMonths(months);
        } else {
            dateTime = dateTime.minusMonths(months);
        }

        return dateTime.toDate();
    }

    /**
     * 判断target是否在开始和结束时间之间
     *
     * @param target
     * @param startTime
     * @param endTime
     * @return
     */
    public static boolean isBetweenStartAndEndTime(Date target, Date startTime, Date endTime) {
        if (null == target || null == startTime || null == endTime) {
            return false;
        }
        DateTime dateTime = new DateTime(target);
        return dateTime.isAfter(startTime.getTime()) && dateTime.isBefore(endTime.getTime());
    }
    /**
     * 获取当前月第一天
     * @param month
     * @return String yyyy-MM-dd hh:mm:ss
     */
    public static String getFirstDayOfMonth(int month) {
        Calendar calendar = Calendar.getInstance();
        // 设置月份
        calendar.set(Calendar.MONTH, month - 1);
        // 获取某月最小天数
        int firstDay = calendar.getActualMinimum(Calendar.DAY_OF_MONTH);
        // 设置日历中月份的最小天数
        calendar.set(Calendar.DAY_OF_MONTH, firstDay);
        // 格式化日期
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        return sdf.format(calendar.getTime())+" 00:00:00";
    }

    /**
     * 获取当前月最后一天
     * @param month
     * @return String yyyy-MM-dd hh:mm:ss
     */
    public static String getLastDayOfMonth(int month) {
        Calendar calendar = Calendar.getInstance();
        // 设置月份
        calendar.set(Calendar.MONTH, month - 1);
        // 获取某月最大天数
        int lastDay=0;
        //2月的平年瑞年天数
        if(month==2) {
            // 这个api在计算2020年2月的过程中有问题
            lastDay = calendar.getLeastMaximum(Calendar.DAY_OF_MONTH);
        }else {
            lastDay = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
        }
        // 设置日历中月份的最大天数
        calendar.set(Calendar.DAY_OF_MONTH, lastDay);
        // 格式化日期
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        return sdf.format(calendar.getTime())+" 23:59:59";
    }
}