JAVA 日期Date加减整理

一、充分利用SimpleDateFormatimport java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;public class DateTestUtil {public static void main(String[] args) throws Exception...

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春风化作秋雨

49060人浏览 · 2018-07-30 23:16:25

春风化作秋雨 · 2018-07-30 23:16:25 发布

一、充分利用SimpleDateFormat

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

public class DateTestUtil {


    public static void main(String[] args) throws Exception {

        SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMdd");
        String str="20110823";
        Date dt=sdf.parse(str);
        Calendar rightNow = Calendar.getInstance();
        rightNow.setTime(dt);
        rightNow.add(Calendar.YEAR,-1);//日期减1年
        rightNow.add(Calendar.MONTH,3);//日期加3个月
        rightNow.add(Calendar.DAY_OF_YEAR,10);//日期加10天
        Date dt1=rightNow.getTime();
        String reStr = sdf.format(dt1);
        System.out.println(reStr);

    }

}

注：在Calendar对象的add方法中，第二个参数为正数表示“加”，负数表示“减”。

二、java date 日期加减天数

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

public class DateTest { 

  public static void main(String[] arg){ 
    Date now = new Date();    

    addAndSubtractDaysByGetTime(now,-5); 
    addAndSubtractDaysByGetTime(now,5); 
    addAndSubtractDaysByCalendar(now,-5); 
    addAndSubtractDaysByCalendar(now,5); 
  } 

   public static Date addAndSubtractDaysByGetTime(Date dateTime/*待处理的日期*/,int n/*加减天数*/){ 

     //日期格式 
     SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");  
     SimpleDateFormat dd=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");     

     System.out.println(df.format(new Date(dateTime.getTime() + n * 24 * 60 * 60 * 1000L))); 
     //System.out.println(dd.format(new Date(dateTime.getTime() + n * 24 * 60 * 60 * 1000L))); 
     //注意这里一定要转换成Long类型，要不n超过25时会出现范围溢出，从而得不到想要的日期值 
     return new Date(dateTime.getTime() + n * 24 * 60 * 60 * 1000L); 
   } 

   public static Date addAndSubtractDaysByCalendar(Date dateTime/*待处理的日期*/,int n/*加减天数*/){ 

     //日期格式 
     SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");  
     SimpleDateFormat dd=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  

     java.util.Calendar calstart = java.util.Calendar.getInstance(); 
       calstart.setTime(dateTime); 

     calstart.add(java.util.Calendar.DAY_OF_WEEK, n);  

     System.out.println(df.format(calstart.getTime())); 
     //System.out.println(dd.format(calstart.getTime())); 
     return calstart.getTime(); 
   } 

}

不推荐这个，代码不够简洁，看着不爽。

三、网上找的别人的，太长，没看，粘过来先

package com.data.utils;

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

public class DateFormat {

    /**
     * 日期减几年
     */
    public static String dateMinusYear(String str) throws Exception {

        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM");
        Date dt = sdf.parse(str);
        Calendar rightNow = Calendar.getInstance();
        rightNow.setTime(dt);
        rightNow.add(Calendar.YEAR, -1);// 日期减1年
        Date dt1 = rightNow.getTime();
        String reStr = sdf.format(dt1);
        return reStr;
    }

    /**
     * 日期加几年
     */
    public static String dateAddYear(String str) throws Exception {

        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM");
        Date dt = sdf.parse(str);
        Calendar rightNow = Calendar.getInstance();
        rightNow.setTime(dt);
        rightNow.add(Calendar.YEAR, 1);// 日期加1年
        Date dt1 = rightNow.getTime();
        String reStr = sdf.format(dt1);
        return reStr;
    }

    /**
     * 日期减几月
     */
    public static String dateMinusMonth(String str) throws Exception {

        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM");
        Date dt = sdf.parse(str);//将字符串生成Date
        Calendar rightNow = Calendar.getInstance();
        rightNow.setTime(dt);//使用给定的 Date 设置此 Calendar 的时间。 
        rightNow.add(Calendar.MONTH, -1);// 日期减1个月
        Date dt1 = rightNow.getTime();//返回一个表示此 Calendar 时间值的 Date 对象。
        String reStr = sdf.format(dt1);//将给定的 Date 格式化为日期/时间字符串，并将结果添加到给定的 StringBuffer。
        return reStr;
    }

    /**
     * 日期加几月
     */
    public static String dateAddMonth(String str) throws Exception {

        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMM");
        Date dt = sdf.parse(str);
        Calendar rightNow = Calendar.getInstance();
        rightNow.setTime(dt);
        rightNow.add(Calendar.MONTH, 1);// 日期加3个月
        // rightNow.add(Calendar.DAY_OF_YEAR,10);//日期加10天
        Date dt1 = rightNow.getTime();
        String reStr = sdf.format(dt1);
        return reStr;
    }

    /**
     * 获取当前年月的第一个月的str
     *
     * @param str 201505
     * @return 201501
     * @throws Exception
     */
    public static String dateOneMonth(String str) {

        str = str.substring(0, str.length() - 2);
        str = str + "01";
        return str;
    }

    /**
     * 算出所选月份距离一月份有几个月。
     *
     * @param str 201509
     * @return 9
     */
    public static int dateDistanceMonth(String str) {

        int i = Integer.parseInt(str);
        int j = Integer.parseInt(DateFormat.dateOneMonth(str));
        System.out.println(i - j);
        return i - j + 1;
    }

    /**
     * 获取两个时间的时间差，精确到毫秒
     *
     * @param str
     * @return
     */
    public static String TimeDifference(long start, long end) {

        long between = end - start;
        long day = between / (24 * 60 * 60 * 1000);
        long hour = (between / (60 * 60 * 1000) - day * 24);
        long min = ((between / (60 * 1000)) - day * 24 * 60 - hour * 60);
        long s = (between / 1000 - day * 24 * 60 * 60 - hour * 60 * 60 - min * 60);
        long ms = (between - day * 24 * 60 * 60 * 1000 - hour * 60 * 60 * 1000
                - min * 60 * 1000 - s * 1000);
        String timeDifference = day + "天" + hour + "小时" + min + "分" + s + "秒" + ms
                + "毫秒";
        return timeDifference;
    }
}

    /**
     * 获取24小时、一周、一个月的起始时间
     *
     * @param timeInterval : DAY_TIME_INTERVAL WEEK_TIME_INTERVAL MONTH_TIME_INTERVAL
     * @return "yyyy-mm-dd hh:mm:ss"
     */
    public static String getStartTime(int timeInterval) {
        Calendar cal = Calendar.getInstance();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        if (DAY_TIME_INTERVAL == timeInterval) {// 获取24小时的起始时间
            cal.set(Calendar.HOUR_OF_DAY, 0);
            cal.set(Calendar.MINUTE, 0);
            cal.set(Calendar.SECOND, 0);
            String startTime = sdf.format(cal.getTime());
            return startTime;
        } else if (WEEK_TIME_INTERVAL == timeInterval) {
            int weekday = cal.get(Calendar.DAY_OF_WEEK) - 1;
            cal.add(Calendar.DATE, -weekday);
            cal.set(Calendar.HOUR_OF_DAY, 0);
            cal.set(Calendar.MINUTE, 0);
            cal.set(Calendar.SECOND, 0);
            String startTime = sdf.format(cal.getTime());
            return startTime;
        } else if (MONTH_TIME_INTERVAL == timeInterval) {
            int dayofmonthMin = cal.getActualMinimum(Calendar.DAY_OF_MONTH);
            // c.add(Calendar.DATE, -dayofmonth);
            cal.set(Calendar.DATE, dayofmonthMin);
            cal.set(Calendar.HOUR_OF_DAY, 0);
            cal.set(Calendar.MINUTE, 0);
            cal.set(Calendar.SECOND, 0);
            String startTime = sdf.format(cal.getTime());
            return startTime;
        }
        return null;
    }

    /**
     * 获取24小时、一周、一个月的结束时间
     *
     * @param timeInterval : DAY_TIME_INTERVAL WEEK_TIME_INTERVAL MONTH_TIME_INTERVAL
     * @return "yyyy-mm-dd hh:mm:ss"
     */
    public static String getEndTime(int timeInterval) {
        Calendar cal = Calendar.getInstance();
        cal.setTimeZone(TimeZone.getTimeZone("GMT+8"));
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        if (DAY_TIME_INTERVAL == timeInterval) {
            cal.set(Calendar.HOUR_OF_DAY, 23);
            cal.set(12, 59);
            cal.set(13, 59);
            long date = cal.getTimeInMillis();
            String endTime = sdf.format(new Date(date));
            return endTime;
        } else if (WEEK_TIME_INTERVAL == timeInterval) {
            int weekday = cal.get(Calendar.DAY_OF_WEEK) - 1;
            cal.add(Calendar.DATE, -weekday);
            cal.add(Calendar.DATE, 6);
            cal.set(Calendar.HOUR_OF_DAY, 23);
            cal.set(12, 59);
            cal.set(13, 59);
            long date = cal.getTimeInMillis();
            String endTime = sdf.format(new Date(date));
            return endTime;
        } else if (MONTH_TIME_INTERVAL == timeInterval) {
            int dayOfMonthMax = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
            cal.set(Calendar.DATE, dayOfMonthMax);
            cal.set(Calendar.HOUR_OF_DAY, 23);
            cal.set(Calendar.MINUTE, 59);
            cal.set(Calendar.SECOND, 59);
            String endTime = sdf.format(cal.getTime());
            return endTime;
        }
        return null;
    }

    /**
     * 判断dateStr是否在start和end中间，start和end都可以为null yyyyMMddHHmmss或者yyyyMMdd格式
     *
     * @param dateStr
     * @param start
     * @param end
     * @return
     * @author you.xu
     * @date 2015年8月19日下午3:11:46
     */
    public static boolean checkDateVal(String dateStr, String start, String end) {
        boolean isDateRight = false;
        Date date = null;
        Date startDate = null;
        Date endDate = null;
        SimpleDateFormat sdf = null;
        // 判断日期格式
        if (14 == dateStr.length()) {
            sdf = new SimpleDateFormat("yyyyMMddHHmmss");
        } else if (8 == dateStr.length()) {
            sdf = new SimpleDateFormat("yyyyMMdd");
        } else
            return false;

        try {
            // 更改判断日期格式
            date = sdf.parse(dateStr);
        } catch (ParseException e) {
            log.error(e, e);
        }

        if ((start == null) && (end != null)) {
            try {
                endDate = sdf.parse(end);
            } catch (ParseException ex1) {
                log.error(ex1, ex1);
            }
            if ((date != null) && (endDate != null))// Check parameters for
            {
                if (date.compareTo(endDate) <= 0)
                    isDateRight = true;
            }
        } else if ((start != null) && (end == null)) {
            try {
                startDate = sdf.parse(start);
            } catch (ParseException ex1) {
                log.error(ex1, ex1);
            }
            if ((date != null) && (startDate != null)) {
                if (date.compareTo(startDate) >= 0)
                    isDateRight = true;
            }
        } else if ((start != null) && (end != null)) {
            try {
                startDate = sdf.parse(start);
                endDate = sdf.parse(end);
            } catch (ParseException ex2) {
                System.out.println(ex2.toString());
            }
            if ((startDate != null) && (date != null) && (endDate != null)) {
                if ((date.compareTo(startDate) >= 0)
                        && (date.compareTo(endDate) <= 0))
                    isDateRight = true;
            }
        }
        return isDateRight;
    }

    /**
     * 判断dateStr是否在start和end中间，start和end都可以为null long形格式
     *
     * @param dateStr
     * @param start
     * @param end
     * @return
     * @author you.xu
     * @date 2015年8月19日下午3:12:35
     */
    public static boolean checkDateV(String dateStr, String start, String end) {
        boolean isDateRight = false;
        long date = -1;
        long fromDate = -1;
        long toDate = -1;

        date = java.lang.Long.parseLong(dateStr);

        if ((start == null) && (end == null)) {
            isDateRight = true;
        } else if ((start == null) && (end != null)) {
            try {
                toDate = java.lang.Long.parseLong(end);
            } catch (NumberFormatException nfe) {
                log.error(nfe, nfe);
            }
            if (date <= toDate) {
                isDateRight = true;
            }
        } else if ((start != null) && (end == null)) {
            try {
                fromDate = java.lang.Long.parseLong(start);
            } catch (NumberFormatException nfe) {
                log.error(nfe, nfe);
            }

            if (date >= fromDate) {
                isDateRight = true;
            }
        } else if ((start != null) && (end != null)) {
            try {
                toDate = java.lang.Long.parseLong(end);
                fromDate = java.lang.Long.parseLong(start);
            } catch (NumberFormatException nfe) {
                log.error(nfe, nfe);
            }

            if ((date <= toDate) && (date >= fromDate)) {
                isDateRight = true;
            }
        }
        return isDateRight;
    }

四、自己的方法的，简单说下需求，由于数据库里的存储类型是 “2017-07-04 12：00：00”，要按当前时间向前检索传进来的天数（noTradeDays），利用java.util的GregorianCalendar，结合SimpleDateFormat，完成当前时间逆推的需求

        /**
         * add by lee 2017/7/4 
         * 连续n天无交易
         */
        if (!StringUtils.isEmpty(noTradeDays)) {
            **SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            GregorianCalendar gc=new GregorianCalendar(); 
            gc.setTime(new Date());
            gc.add(5, -Integer.parseInt(noTradeDays));**
            String cardSql="select posid from card where usetime between "+"'"+sdf.format(gc.getTime())+"'"+" and "+"'"+sdf.format(new Date())+"'"+" group by posid";
            List<Card> cards = CardService.cardDAO.executeQuery(new Query(cardSql));
            if (cards.size()>0) {
                StringBuffer sb=new StringBuffer();
                for (Card posId : cards) {
                    if (!StringUtils.isEmpty(posId.getPosid())) {
                        sb.append("'").append(posId.getPosid()).append("'").append(",");
                    }
                }
                if (sb.length()>0) {
                    sql_add +=" and posid not in ("+sb.substring(0, sb.length()-1).toString()+")";
                }
            }
        }

恩，就是这样子了，总之就是灵活运用java.util里关于日期的相关类。

出处：
Java对日期Date类进行加减运算一二三_hacker_Lees的博客-CSDN博客_date加减日期