Java中String、Date、LocalDate互相转换工具类

野性酷女 2022-05-26 00:51 394阅读 0赞

**该工具类实现的功能有：**

**1.String日期转Date**

**2.Date日期转String**

**3.Date日期转LocaDate**

**4.LocalDate转Date**

**5.获取当前日期（String）**

**6.获取当前日期（Date）**

**7.获取两个日期之间的间隔**

**8.获取日期的星期**

**9.比较两个日期的大小**

**10.日期转为时间戳**

**11.时间戳转日期**

**12.去除日期连接符号（“-”），转为long**

**13.日期加上相应的天数**

代码如下所示：

import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.time.Instant;
    import java.time.LocalDate;
    import java.time.ZoneId;
    import java.time.ZonedDateTime;
    import java.time.format.DateTimeFormatter;
    import java.util.*;
    /**
     *
     * 日期工具类
     * @since 1.0
     * @date 2018-04-21
     * @author 林老师带你学编程 微信号码：lzqcode
     *
     */
    public class DateUtils{
        public static String F19 = "yyyy-MM-dd HH:mm:ss";
    
        public static String F14 = "yyyyMMddHHmmss";
    
        public static String F10 = "yyyy-MM-dd";
    
        public static String F8 = "yyyyMMdd";
    
        public static String[] dataStringFormats = {F8, F10, F14, F19, "yyyy/MM/dd", "yyyy/MM/dd HH:mm", "yyyy/MM/dd HH:mm:ss", "yyyy-MM-dd HH:mm"};
    
        /**
         * 将字符串转换为long类型的值(不包含-符号)
         * @param dateString 2016-10-12
         * @return 20161012
         */
        public static long stringToDateLong(String dateString) {
            String[] dates = dateString.split("-");
            return Long.valueOf(dates[0] + dates[1] + dates[2]);
        }
    
        /**
         * 将日期转化为默认的格式显示
         * @param date Date实例
         * @return 2017-06-06
         */
        public static String dateToString(Date date) {
            return dateToString(date, F10);
        }
    
        /**
         * @param date Date实例
         * @param format yyyy-MM-dd
         * @return 2017-06-06
         */
        public static String dateToString(Date date, String format) {
            if (date == null) {
                return null;
            }
            SimpleDateFormat sf = new SimpleDateFormat(format);
            return sf.format(date);
        }
    
        /**
         * 时间戳转默认字符串日期
         * @param time 1496739850253
         * @return 2017-06-06
         */
        public static String longToString(long time) {
            return longToString(time, F10);
        }
    
        /**
         * 时间戳转字符串日期（格式可以自己选择）
         * @param time 1496739850253
         * @param format yyyy-MM-dd
         * @return 2017-06-06
         */
        public static String longToString(long time, String format) {
            SimpleDateFormat sf = new SimpleDateFormat(format);
            return sf.format(new Date(time));
        }
    
        /**
         * 在指定日期上加上一定天数获得新的日期
         * @param day 2016-06-06
         * @param addDay 10
         * @return 2016-06-16
         */
        public static String getNextDay(String day, int addDay) {
            Calendar calendar = getCalendar(day);
            calendar.add(Calendar.DAY_OF_MONTH, addDay);
            return getDateString(calendar);
        }
    
        /**
         * 获取当前时间（包含小时、分、秒）
         * @return 2016-06-06 10:20:10
         */
        public static String getCurrTime() {
            return dateToString(new Date(), F19);
        }
    
        /**
         * 获取当前日期（不包含小时、分、秒）
         * @return 2016-06-06
         */
        public static String getCurrDate() {
            return dateToString(new Date(), F10);
        }
    
        /**
         * 获取日期相距天数
         * @param startDate 2016-06-06
         * @param endDate 2016-06-10
         * @return int 4
         */
        public static int getCompareDate(String startDate, String endDate) {
            try {
                SimpleDateFormat formatter = new SimpleDateFormat(F10);
                Date date1 = formatter.parse(startDate);
                Date date2 = formatter.parse(endDate);
                long l = date2.getTime() - date1.getTime() + 1000;
                long d = l / (24 * 60 * 60 * 1000);
                return (int) d;
            } catch (ParseException e) {
            }
            return 0;
        }
    
        private static Calendar getCalendar(String day) {
            Calendar cal = Calendar.getInstance();
            cal.set(Integer.parseInt(day.substring(0, 4)), Integer.parseInt(day.substring(5, 7)) - 1, Integer.parseInt(day.substring(8, 10)), 0, 0, 0);
            return cal;
        }
    
        /**
         * 当前时间几小时相差多少时间
         * @param hour
         * @return
         * @since 2017年8月18日
         */
        public static Date getAddHourTime(int hour) {
            Calendar dalendar = Calendar.getInstance();
            dalendar.add(Calendar.HOUR_OF_DAY, hour);
            return dalendar.getTime();
        }
    
        /**
         * 将Calendar转换为日期字符串（字符串的格式：2018-04-21）
         * @param cale
         * @return
         */
        public static String getDateString(Calendar cale) {
            int year = cale.get(Calendar.YEAR);
            int month = cale.get(Calendar.MONTH) + 1;
            int day = cale.get(Calendar.DAY_OF_MONTH);
            return year + "-" + (month < 10 ? "0" + month : month + "") + "-" + (day < 10 ? "0" + day : day + "");
        }
    
        /**
         * Calendar转为指定格式的日期字符串
         * @param cale
         * @param format
         * @return
         */
        public static String getDateString(Calendar cale, String format) {
            return dateToString(cale.getTime(), format);
        }
    
        /**
         *计算两个日期之间相差的时间
         * @param sDate
         * @param eDate
         * @return
         * @throws Exception
         */
        public static long substract(String sDate, String eDate) {
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            Date d1 = null;
            try {
                d1 = sdf.parse(sDate);
            } catch (ParseException e) {
                e.printStackTrace();
            }
            Date d2 = null;
            try {
                d2 = sdf.parse(eDate);
            } catch (ParseException e) {
                e.printStackTrace();
            }
            return (d2.getTime() - d1.getTime() + 1000000) / (3600 * 24 * 1000);
        }
    
        /**
         * 返回当前日期, 格式：yyyy-mm-dd 使用方法： Date.getToday();
         * @return 2018-04-21
         */
        public static String getToday() {
            Calendar rightNow = Calendar.getInstance();
            int year = rightNow.get(Calendar.YEAR);
            int month = rightNow.get(Calendar.MONTH) + 1;
            int day = rightNow.get(Calendar.DAY_OF_MONTH);
            return year + "-" + (month < 10 ? "0" + month : month + "") + "-" + (day < 10 ? "0" + day : day + "");
        }
    
        /**
         * 字符串的日期格式的计算
         * @param smdate 较大时结果为负数
         * @param bdate 较大时结果为正数
         * @return int
         * @throws ParseException
         */
        public static int daysBetween(String smdate, String bdate) throws ParseException {
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            Calendar cal = Calendar.getInstance();
            cal.setTime(sdf.parse(smdate));
            long time1 = cal.getTimeInMillis();
            cal.setTime(sdf.parse(bdate));
            long time2 = cal.getTimeInMillis();
            long between_days = (time2 - time1) / (1000 * 3600 * 24);
            return Integer.parseInt(String.valueOf(between_days));
        }
    
        /**
         * 获取yyyy-MM-dd格式日期的所在星期数
         * 例如2018-04-21得到的结果是7
         * @param dateStr
         * @return
         */
        public static int getWeekDay(String dateStr) {
            int week = -1;
            SimpleDateFormat ft = new SimpleDateFormat("yyyy-MM-dd");
            Date date;
            try {
                date = ft.parse(dateStr);
                if (date != null) {
                    Calendar cal = Calendar.getInstance();
                    cal.setTime(date);
                    week = cal.get(Calendar.DAY_OF_WEEK);
                }
            } catch (ParseException e) {
                e.printStackTrace();
            }
            return week;
        }
    
         * 将20180421转化为2016-04-21
         * @param day
         * @return
         */
        public static String intToDay(long day) {
            String dayStr = String.valueOf(day);
            return new StringBuilder().append(dayStr.substring(0, 4)).append("-").append(dayStr.substring(4, 6)).append("-").append(dayStr.substring(6, 8)).toString();
        }
    
        public static long dayToInt(String day) {
            return Long.parseLong(day.replaceAll("-", ""));
        }
    
    
        /**
         * 判断某一日期是星期几，星期天为第7天
         * @param day
         * @return
         */
        public static String getDayOfWeekCh(String day) {
            int dayInt;
            Calendar cal = Calendar.getInstance();
            cal.set(Integer.parseInt(day.substring(0, 4)), Integer.parseInt(day.substring(5, 7)) - 1, Integer.parseInt(day.substring(8, 10)), 0, 0, 0);
            dayInt = cal.get(Calendar.DAY_OF_WEEK) - 1;
            if (dayInt == 0) {
                dayInt = 7;
            }
            return dayInt + "";
        }
    
        /**
         * 日期解析
         * @param source
         * @param format
         * @return
         * @throws ParseException
         */
        public static Date parseDate(String source, String format) {
            SimpleDateFormat sdf = new SimpleDateFormat(format);
            try {
                return sdf.parse(source);
            } catch (ParseException e) {
                return null;
            }
        }
    
        /**
         * 获取指定年月份的第一天
         * @param year
         * @param month
         * @return
         */
        public static String monthFirstDay(int year, int month) {
            Calendar cal = Calendar.getInstance();
            //设置年份
            cal.set(Calendar.YEAR, year);
            //设置月份
            cal.set(Calendar.MONTH, month - 1);
            //获取某月最小天数
            int firstDay = cal.getActualMinimum(Calendar.DAY_OF_MONTH);
            //设置日历中月份的最小天数
            cal.set(Calendar.DAY_OF_MONTH, firstDay);
            //格式化日期
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            String firstDayOfMonth = sdf.format(cal.getTime());
            return firstDayOfMonth;
        }
    
        /**
         * 获取指定年月份的最后一天
         * @param year
         * @param month
         * @return
         */
        public static String monthLastDay(int year, int month) {
            Calendar cal = Calendar.getInstance();
            //设置年份
            cal.set(Calendar.YEAR, year);
            //设置月份
            cal.set(Calendar.MONTH, month - 1);
            //获取某月最小天数
            int firstDay = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
            //设置日历中月份的最小天数
            cal.set(Calendar.DAY_OF_MONTH, firstDay);
            //格式化日期
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            String lastDayOfMonth = sdf.format(cal.getTime());
            return lastDayOfMonth;
        }
    
    
        /**
         * Date类型转LocalDate类型
         * @param date
         * @return
         */
        public static LocalDate dateToLocalDate(Date date) {
            Instant instant = date.toInstant();
            ZoneId zoneId = ZoneId.systemDefault();
            LocalDate localPriceDate = instant.atZone(zoneId).toLocalDate();
            return localPriceDate;
        }
    
        /**
         * LocalDate类型转Date类型
         * @param localDate
         * @return Date
         */
        public static Date localDateToDate(LocalDate localDate) {
            ZoneId zoneId = ZoneId.systemDefault();
            ZonedDateTime zdt = localDate.atStartOfDay(zoneId);
            Date date = Date.from(zdt.toInstant());
            return date;
        }
    }

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[20180421211631992]: /images/20220526/803d452b32bd49698bec49b22dcb5b19.png