Java时间类（转）

 package com.chinagas.common.utils;

 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;

 public class DateUtils {

     public static final String DATE_TIME_PATTERN = "yyyy-MM-dd HH:mm:ss";
     public static final String MINUTE_PATTERN = "yyyy-MM-dd HH:mm";
     public static final String HOUR_PATTERN = "yyyy-MM-dd HH:mm:ss";
     public static final String DATE_PATTERN = "yyyy-MM-dd";
     public static final String MONTH_PATTERN = "yyyy-MM";
     public static final String YEAR_PATTERN = "yyyy";
     public static final String MINUTE_ONLY_PATTERN = "mm";
     public static final String HOUR_ONLY_PATTERN = "HH";

     /**
      * 日期相加减天数
      * @param date 如果为Null，则为当前时间
      * @param days 加减天数
      * @param includeTime 是否包括时分秒,true表示包含
      * @return
      * @throws ParseException
      */
     public static Date dateAdd(Date date, int days, boolean includeTime) throws ParseException{
         if(date == null){
             date = new Date();
         }
         if(!includeTime){
             SimpleDateFormat sdf = new SimpleDateFormat(DateUtils.DATE_PATTERN);
             date = sdf.parse(sdf.format(date));
         }
         Calendar cal = Calendar.getInstance();
         cal.setTime(date);
         cal.add(Calendar.DATE, days);
         return cal.getTime();
     }

     /**
      * 时间格式化成字符串
      * @param date Date
      * @param pattern StrUtils.DATE_TIME_PATTERN || StrUtils.DATE_PATTERN， 如果为空，则为yyyy-MM-dd
      * @return
      * @throws ParseException
      */
     public static String dateFormat(Date date, String pattern) throws ParseException{
         if(StrUtils.isBlank(pattern)){
             pattern = DateUtils.DATE_PATTERN;
         }
         SimpleDateFormat sdf = new SimpleDateFormat(pattern);
         return sdf.format(date);
     }

     /**
      * 字符串解析成时间对象
      * @param dateTimeString String
      * @param pattern StrUtils.DATE_TIME_PATTERN || StrUtils.DATE_PATTERN，如果为空，则为yyyy-MM-dd
      * @return
      * @throws ParseException
      */
     public static Date dateParse(String dateTimeString, String pattern) throws ParseException{
         if(StrUtils.isBlank(pattern)){
             pattern = DateUtils.DATE_PATTERN;
         }
         SimpleDateFormat sdf = new SimpleDateFormat(pattern);
         return sdf.parse(dateTimeString);
     }

     /**
      * 将日期时间格式成只有日期的字符串（可以直接使用dateFormat，Pattern为Null进行格式化）
      * @param dateTime Date
      * @return
      * @throws ParseException
      */
     public static String dateTimeToDateString(Date dateTime) throws ParseException{
         String dateTimeString = DateUtils.dateFormat(dateTime, DateUtils.DATE_TIME_PATTERN);
         return dateTimeString.substring(0, 10);
     }

     /**
      * 当时、分、秒为00:00:00时，将日期时间格式成只有日期的字符串，
      * 当时、分、秒不为00:00:00时，直接返回
      * @param dateTime Date
      * @return
      * @throws ParseException
      */
     public static String dateTimeToDateStringIfTimeEndZero(Date dateTime) throws ParseException{
         String dateTimeString = DateUtils.dateFormat(dateTime, DateUtils.DATE_TIME_PATTERN);
         if(dateTimeString.endsWith("00:00:00")){
             return dateTimeString.substring(0, 10);
         }else{
             return dateTimeString;
         }
     }

     /**
      * 将日期时间格式成日期对象，和dateParse互用
      * @param dateTime Date
      * @return Date
      * @throws ParseException
      */
     public static Date dateTimeToDate(Date dateTime) throws ParseException{
         Calendar cal = Calendar.getInstance();
         cal.setTime(dateTime);
         cal.set(Calendar.HOUR_OF_DAY, 0);
         cal.set(Calendar.MINUTE, 0);
         cal.set(Calendar.SECOND, 0);
         cal.set(Calendar.MILLISECOND, 0);
         return cal.getTime();
     }

     /**
      * 时间加减小时
      * @param startDate 要处理的时间，Null则为当前时间
      * @param hours 加减的小时
      * @return Date
      */
     public static Date dateAddHours(Date startDate, int hours) {
         if (startDate == null) {
             startDate = new Date();
         }
         Calendar c = Calendar.getInstance();
         c.setTime(startDate);
         c.set(Calendar.HOUR, c.get(Calendar.HOUR) + hours);
         return c.getTime();
     }

     /**
      * 时间加减分钟
      * @param startDate 要处理的时间，Null则为当前时间
      * @param minutes 加减的分钟
      * @return
      */
     public static Date dateAddMinutes(Date startDate, int minutes) {
         if (startDate == null) {
             startDate = new Date();
         }
         Calendar c = Calendar.getInstance();
         c.setTime(startDate);
         c.set(Calendar.MINUTE, c.get(Calendar.MINUTE) + minutes);
         return c.getTime();
     }

     /**
      * 时间加减秒数
      * @param startDate 要处理的时间，Null则为当前时间
      * @param minutes 加减的秒数
      * @return
      */
     public static Date dateAddSeconds(Date startDate, int seconds) {
         if (startDate == null) {
             startDate = new Date();
         }
         Calendar c = Calendar.getInstance();
         c.setTime(startDate);
         c.set(Calendar.SECOND, c.get(Calendar.SECOND) + seconds);
         return c.getTime();
     }

     /**
      * 时间加减天数
      * @param startDate 要处理的时间，Null则为当前时间
      * @param days 加减的天数
      * @return Date
      */
     public static Date dateAddDays(Date startDate, int days) {
         if (startDate == null) {
             startDate = new Date();
         }
         Calendar c = Calendar.getInstance();
         c.setTime(startDate);
         c.set(Calendar.DATE, c.get(Calendar.DATE) + days);
         return c.getTime();
     }

     /**
      * 时间加减月数
      * @param startDate 要处理的时间，Null则为当前时间
      * @param months 加减的月数
      * @return Date
      */
     public static Date dateAddMonths(Date startDate, int months) {
         if (startDate == null) {
             startDate = new Date();
         }
         Calendar c = Calendar.getInstance();
         c.setTime(startDate);
         c.set(Calendar.MONTH, c.get(Calendar.MONTH) + months);
         return c.getTime();
     }

     /**
      * 时间加减年数
      * @param startDate 要处理的时间，Null则为当前时间
      * @param years 加减的年数
      * @return Date
      */
     public static Date dateAddYears(Date startDate, int years) {
         if (startDate == null) {
             startDate = new Date();
         }
         Calendar c = Calendar.getInstance();
         c.setTime(startDate);
         c.set(Calendar.YEAR, c.get(Calendar.YEAR) + years);
         return c.getTime();
     }  

     /**
      * 时间比较（如果myDate>compareDate返回1，<返回-1，相等返回0）
      * @param myDate 时间
      * @param compareDate 要比较的时间
      * @return int
      */
     public static int dateCompare(Date myDate, Date compareDate) {
         Calendar myCal = Calendar.getInstance();
         Calendar compareCal = Calendar.getInstance();
         myCal.setTime(myDate);
         compareCal.setTime(compareDate);
         return myCal.compareTo(compareCal);
     }

     /**
      * 获取两个时间中最小的一个时间
      * @param date
      * @param compareDate
      * @return
      */
     public static Date dateMin(Date date, Date compareDate) {
         if(date == null){
             return compareDate;
         }
         if(compareDate == null){
             return date;
         }
         if(1 == dateCompare(date, compareDate)){
             return compareDate;
         }else if(-1 == dateCompare(date, compareDate)){
             return date;
         }
         return date;
     }

     /**
      * 获取两个时间中最大的一个时间
      * @param date
      * @param compareDate
      * @return
      */
     public static Date dateMax(Date date, Date compareDate) {
         if(date == null){
             return compareDate;
         }
         if(compareDate == null){
             return date;
         }
         if(1 == dateCompare(date, compareDate)){
             return date;
         }else if(-1 == dateCompare(date, compareDate)){
             return compareDate;
         }
         return date;
     }

     /**
      * 获取两个日期（不含时分秒）相差的天数，不包含今天
      * @param startDate
      * @param endDate
      * @return
      * @throws ParseException
      */
     public static int dateBetween(Date startDate, Date endDate) throws ParseException {
         Date dateStart = dateParse(dateFormat(startDate, DATE_PATTERN), DATE_PATTERN);
         Date dateEnd = dateParse(dateFormat(endDate, DATE_PATTERN), DATE_PATTERN);
         return (int) ((dateEnd.getTime() - dateStart.getTime())/1000/60/60/24);
     }

     /**
      * 获取两个日期（不含时分秒）相差的天数，包含今天
      * @param startDate
      * @param endDate
      * @return
      * @throws ParseException
      */
     public static int dateBetweenIncludeToday(Date startDate, Date endDate) throws ParseException {
         return dateBetween(startDate, endDate) + 1;
     }

     /**
      * 获取日期时间的年份，如2017-02-13，返回2017
      * @param date
      * @return
      */
     public static int getYear(Date date) {
         Calendar cal = Calendar.getInstance();
         cal.setTime(date);
         return cal.get(Calendar.YEAR);
     }

     /**
      * 获取日期时间的月份，如2017年2月13日，返回2
      * @param date
      * @return
      */
     public static int getMonth(Date date) {
         Calendar cal = Calendar.getInstance();
         cal.setTime(date);
         return cal.get(Calendar.MONTH) + 1;
     }

     /**
      * 获取日期时间的第几天（即返回日期的dd），如2017-02-13，返回13
      * @param date
      * @return
      */
     public static int getDate(Date date) {
         Calendar cal = Calendar.getInstance();
         cal.setTime(date);
         return cal.get(Calendar.DATE);
     }

     /**
      * 获取日期时间当月的总天数，如2017-02-13，返回28
      * @param date
      * @return
      */
     public static int getDaysOfMonth(Date date) {
         Calendar cal = Calendar.getInstance();
         cal.setTime(date);
         return cal.getActualMaximum(Calendar.DATE);
     }

     /**
      * 获取日期时间当年的总天数，如2017-02-13，返回2017年的总天数
      * @param date
      * @return
      */
     public static int getDaysOfYear(Date date) {
         Calendar cal = Calendar.getInstance();
         cal.setTime(date);
         return cal.getActualMaximum(Calendar.DAY_OF_YEAR);
     }

     /**
      * 根据时间获取当月最大的日期
      * <li>2017-02-13，返回2017-02-28</li>
      * <li>2016-02-13，返回2016-02-29</li>
      * <li>2016-01-11，返回2016-01-31</li>
      * @param date Date
      * @return
      * @throws Exception
      */
     public static Date maxDateOfMonth(Date date) throws Exception {
         Calendar cal = Calendar.getInstance();
         cal.setTime(date);
         int value = cal.getActualMaximum(Calendar.DATE);
         return dateParse(dateFormat(date, MONTH_PATTERN) + "-" + value, null);
     }

     /**
      * 根据时间获取当月最小的日期，也就是返回当月的1号日期对象
      * @param date Date
      * @return
      * @throws Exception
      */
     public static Date minDateOfMonth(Date date) throws Exception {
         Calendar cal = Calendar.getInstance();
         cal.setTime(date);
         int value = cal.getActualMinimum(Calendar.DATE);
         return dateParse(dateFormat(date, MONTH_PATTERN) + "-" + value, null);
     }

     public static void main(String[] args) throws Exception {
         /*System.out.println(dateTimeToDate(new Date()));
         System.out.println(dateParse("2017-02-04 14:58:20", null));
         System.out.println(dateTimeToDateStringIfTimeEndZero(new Date()));
         System.out.println(dateTimeToDateStringIfTimeEndZero(dateTimeToDate(new Date())));*/
         //System.out.println(dateBetween(dateParse("2017-01-30", null), dateParse("2017-02-01", null)));
         //System.out.println(dateBetweenIncludeToday(dateParse("2017-01-30", null), dateParse("2017-02-01", null)));
         System.out.println(getDate(dateParse("2017-01-17", null)));
         /*
         System.out.println(getDaysOfMonth(dateParse("2017-02-01", null)));
         System.out.println(getDaysOfYear(dateParse("2017-01-30", null)));*/
         //System.out.println(dateFormat(dateAddMonths(dateParse("2017-02-07", StrUtils.MONTH_PATTERN), -12), StrUtils.MONTH_PATTERN));
         /*System.out.println(dateFormat(maxDateOfMonth(dateParse("2016-02", "yyyy-MM")), null));
         System.out.println(dateFormat(minDateOfMonth(dateParse("2016-03-31", null)), null));*/
     }

 }

原文链接https://www.cnblogs.com/fanshuyao/p/6365099.html