Java日期工具类DateUtils实例详解
作者：IT狗探求
这篇文章主要为大家详细介绍了Java日期工具类DateUtils实例，文中示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下
在项目开发中，日期是我们必不可少的的一部分，本文将总结代码开发中的关于日期常用的一些方法，以方便自己后期使用。下面直接上菜了：
package com.example.util;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
/**
* 日期常用方法
*
* @author
*
*/
public class DateUtils {
/**
* 常用变量
*/
public static final String DATE_FORMAT_FULL = "yyyy-MM-dd HH:mm:ss";
public static final String DATE_FORMAT_YMD = "yyyy-MM-dd";
public static final String DATE_FORMAT_HMS = "HH:mm:ss";
public static final String DATE_FORMAT_HM = "HH:mm";
public static final String DATE_FORMAT_YMDHM = "yyyy-MM-dd HH:mm";
public static final String DATE_FORMAT_YMDHMS = "yyyyMMddHHmmss";
public static final long ONE_DAY_MILLS = 3600000 * 24;
public static final int WEEK_DAYS = 7;
private static final int dateLength = DATE_FORMAT_YMDHM.length();
/**
* 日期转换为制定格式字符串
*
* @param time
* @param format
* @return
*/
public static String formatDateToString(Date time, String format) {
SimpleDateFormat sdf = new SimpleDateFormat(format);
return sdf.format(time);
}
/**
* 字符串转换为制定格式日期
* (注意：当你输入的日期是2014-12-21 12:12，format对应的应为yyyy-MM-dd HH:mm
* 否则异常抛出)
* @param date
* @param format
* @return
* @throws ParseException
* @
*/
public static Date formatStringToDate(String date, String format) {
SimpleDateFormat sdf = new SimpleDateFormat(format);
try {
return sdf.parse(date);
} catch (ParseException ex) {
ex.printStackTrace();
throw new RuntimeException(ex.toString());
}
}
/**
* 判断一个日期是否属于两个时段内
* @param time
* @param timeRange
* @return
*/
public static boolean isTimeInRange(Date time, Date[] timeRange) {
return (!time.before(timeRange[0]) && !time.after(timeRange[1]));
}
/**
* 从完整的时间截取精确到分的时间
*
* @param fullDateStr
* @return
*/
public static String getDateToMinute(String fullDateStr) {
return fullDateStr == null ? null
: (fullDateStr.length() >= dateLength ? fullDateStr.substring(
0, dateLength) : fullDateStr);
}
/**
* 返回指定年度的所有周。List中包含的是String[2]对象 string[0]本周的开始日期,string[1]是本周的结束日期。
* 日期的格式为YYYY-MM-DD 每年的第一个周，必须包含星期一且是完整的七天。
* 例如：2009年的第一个周开始日期为2009-01-05，结束日期为2009-01-11。 星期一在哪一年，那么包含这个星期的周就是哪一年的周。
* 例如：2008-12-29是星期一，2009-01-04是星期日，哪么这个周就是2008年度的最后一个周。
*
* @param year
* 格式 YYYY ，必须大于1900年度 小于9999年
* @return @
*/
public static List<String[]> getWeeksByYear(final int year) {
int weeks = getWeekNumOfYear(year);
List<String[]> result = new ArrayList<String[]>(weeks);
int start = 1;
int end = 7;
for (int i = 1; i <= weeks; i++) {
String[] tempWeek = new String[2];
tempWeek[0] = getDateForDayOfWeek(year, i, start);
tempWeek[1] = getDateForDayOfWeek(year, i, end);
result.add(tempWeek);
}
return result;
}
/**
* 计算指定年、周的上一年、周
*
* @param year
* @param week
* @return @
*/
public static int[] getLastYearWeek(int year, int week) {
if (week <= 0) {
throw new IllegalArgumentException("周序号不能小于1！！");
}
int[] result = { week, year };
if (week == 1) {
// 上一年
result[1] -= 1;
// 最后一周
result[0] = getWeekNumOfYear(result[1]);
} else {
result[0] -= 1;
}
return result;
}
/**
* 下一个[周，年]
*
* @param year
* @param week
* @return @
*/
public static int[] getNextYearWeek(int year, int week) {
if (week <= 0) {
throw new IllegalArgumentException("周序号不能小于1！！");
}
int[] result = { week, year };
int weeks = getWeekNumOfYear(year);
if (week == weeks) {
// 下一年
result[1] += 1;
// 第一周
result[0] = 1;
} else {
result[0] += 1;
}
return result;
}
/**
* 计算指定年度共有多少个周。(从周一开始)
*
* @param year
* @return @
*/
public static int getWeekNumOfYear(final int year) {
return getWeekNumOfYear(year, Calendar.MONDAY);
}
/**
* 计算指定年度共有多少个周。
*
* @param year
* yyyy
* @return @
*/
public static int getWeekNumOfYear(final int year, int firstDayOfWeek) {
// 每年至少有52个周 ，最多有53个周。
int minWeeks = 52;
int maxWeeks = 53;
int result = minWeeks;
int sIndex = 4;
String date = getDateForDayOfWeek(year, maxWeeks, firstDayOfWeek);
// 判断年度是否相符，如果相符说明有53个周。
if (date.substring(0, sIndex).equals(year)) {
result = maxWeeks;
}
return result;
}
public static int getWeeksOfWeekYear(final int year) {
Calendar cal = Calendar.getInstance();
cal.setFirstDayOfWeek(Calendar.MONDAY);
cal.setMinimalDaysInFirstWeek(WEEK_DAYS);
cal.set(Calendar.YEAR, year);
return cal.getWeeksInWeekYear();
}
/**
* 获取指定年份的第几周的第几天对应的日期yyyy-MM-dd(从周一开始)
*
* @param year
* @param weekOfYear
* @param dayOfWeek
* @return yyyy-MM-dd 格式的日期 @
*/
public static String getDateForDayOfWeek(int year, int weekOfYear,
int dayOfWeek) {
return getDateForDayOfWeek(year, weekOfYear, dayOfWeek, Calendar.MONDAY);
}
/**
* 获取指定年份的第几周的第几天对应的日期yyyy-MM-dd，指定周几算一周的第一天（firstDayOfWeek）
*
* @param year
* @param weekOfYear
* @param dayOfWeek
* @param firstDayOfWeek
* 指定周几算一周的第一天
* @return yyyy-MM-dd 格式的日期
*/
public static String getDateForDayOfWeek(int year, int weekOfYear,
int dayOfWeek, int firstDayOfWeek) {
Calendar cal = Calendar.getInstance();
cal.setFirstDayOfWeek(firstDayOfWeek);
cal.set(Calendar.DAY_OF_WEEK, dayOfWeek);
cal.setMinimalDaysInFirstWeek(WEEK_DAYS);
cal.set(Calendar.YEAR, year);
cal.set(Calendar.WEEK_OF_YEAR, weekOfYear);
return formatDateToString(cal.getTime(), DATE_FORMAT_YMD);
}
/**
* 获取指定日期星期几
*
* @param datetime
* @throws ParseException
* @
*/
public static int getWeekOfDate(String datetime) throws ParseException {
Calendar cal = Calendar.getInstance();
cal.setFirstDayOfWeek(Calendar.MONDAY);
cal.setMinimalDaysInFirstWeek(WEEK_DAYS);
Date date = formatStringToDate(datetime, DATE_FORMAT_YMD);
cal.setTime(date);
return cal.get(Calendar.DAY_OF_WEEK);
}
/**
* 计算某年某周内的所有日期(从周一开始 为每周的第一天)
*
* @param yearNum
* @param weekNum
* @return @
*/
public static List<String> getWeekDays(int yearNum, int weekNum) {
return getWeekDays(yearNum, weekNum, Calendar.MONDAY);
}
/**
* 计算某年某周内的所有日期(七天)
*
* @param yearNum
* @param weekNum
* @return yyyy-MM-dd 格式的日期列表
*/
public static List<String> getWeekDays(int year, int weekOfYear,
int firstDayOfWeek) {
List<String> dates = new ArrayList<String>();
int dayOfWeek = firstDayOfWeek;
for (int i = 0; i < WEEK_DAYS; i++) {
dates.add(getDateForDayOfWeek(year, weekOfYear, dayOfWeek++,
firstDayOfWeek));
}
return dates;
}
/**
* 获取目标日期的上周、或本周、或下周的年、周信息
*
* @param queryDate
* 传入的时间
* @param weekOffset
* -1:上周 0:本周 1:下周
* @param firstDayOfWeek
* 每周以第几天为首日
* @return
* @throws ParseException
*/
public static int[] getWeekAndYear(String queryDate, int weekOffset,
int firstDayOfWeek) throws ParseException {
Date date = formatStringToDate(queryDate, DATE_FORMAT_YMD);
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
calendar.setFirstDayOfWeek(firstDayOfWeek);
calendar.setMinimalDaysInFirstWeek(WEEK_DAYS);
int year = calendar.getWeekYear();
int week = calendar.get(Calendar.WEEK_OF_YEAR);
int[] result = { week, year };
switch (weekOffset) {
case 1:
result = getNextYearWeek(year, week);
break;
case -1:
result = getLastYearWeek(year, week);
break;
default:
break;
}
return result;
}
/**
* 计算个两日期的天数
*
* @param startDate
* 开始日期字串
* @param endDate
* 结束日期字串
* @return
* @throws ParseException
*/
public static int getDaysBetween(String startDate, String endDate)
throws ParseException {
int dayGap = 0;
if (startDate != null && startDate.length() > 0 && endDate != null
&& endDate.length() > 0) {
Date end = formatStringToDate(endDate, DATE_FORMAT_YMD);
Date start = formatStringToDate(startDate, DATE_FORMAT_YMD);
dayGap = getDaysBetween(start, end);
}
return dayGap;
}
private static int getDaysBetween(Date startDate, Date endDate) {
return (int) ((endDate.getTime() - startDate.getTime()) / ONE_DAY_MILLS);
}
/**
* 计算两个日期之间的天数差
* @param startDate
* @param endDate
* @return
*/
public static int getDaysGapOfDates(Date startDate, Date endDate) {
int date = 0;
if (startDate != null && endDate != null) {
date = getDaysBetween(startDate, endDate);
}
return date;
}
/**
* 计算两个日期之间的年份差距
*
* @param firstDate
* @param secondDate
* @return
*/
public static int getYearGapOfDates(Date firstDate, Date secondDate) {
if (firstDate == null || secondDate == null) {
return 0;
}
Calendar helpCalendar = Calendar.getInstance();
helpCalendar.setTime(firstDate);
int firstYear = helpCalendar.get(Calendar.YEAR);
helpCalendar.setTime(secondDate);
int secondYear = helpCalendar.get(Calendar.YEAR);
return secondYear - firstYear;
}
/**
* 计算两个日期之间的月份差距
*
* @param firstDate
* @param secondDate
* @return
*/
public static int getMonthGapOfDates(Date firstDate, Date secondDate) {
if (firstDate == null || secondDate == null) {
return 0;
}
return (int) ((secondDate.getTime() - firstDate.getTime())
/ ONE_DAY_MILLS / 30);
}
/**
* 计算是否包含当前日期
*
* @param datys
* @return
*/
public static boolean isContainCurrent(List<String> dates) {
boolean flag = false;
SimpleDateFormat fmt = new SimpleDateFormat(DATE_FORMAT_YMD);
Date date = new Date();
String dateStr = fmt.format(date);
for (int i = 0; i < dates.size(); i++) {
if (dateStr.equals(dates.get(i))) {
flag = true;
}
}
return flag;
}
/**
* 从date开始计算time天后的日期
*
* @param date
* @param time
* @return
* @throws ParseException
*/
public static String getCalculateDateToString(String startDate, int time)
throws ParseException {
String resultDate = null;
if (startDate != null && startDate.length() > 0) {
Date date = formatStringToDate(startDate, DATE_FORMAT_YMD);
Calendar c = Calendar.getInstance();
c.setTime(date);
c.set(Calendar.DAY_OF_YEAR, time);
date = c.getTime();
resultDate = formatDateToString(date, DATE_FORMAT_YMD);
}
return resultDate;
}
/**
* 获取从某日期开始计算，指定的日期所在该年的第几周
*
* @param date
* @param admitDate
* @return
* @throws ParseException
* @
*/
public static int[] getYearAndWeeks(String date, String admitDate)
throws ParseException {
Calendar c = Calendar.getInstance();
c.setTime(formatStringToDate(admitDate, DATE_FORMAT_YMD));
int time = c.get(Calendar.DAY_OF_WEEK);
return getWeekAndYear(date, 0, time);
}
/**
* 获取指定日期refDate，前或后一周的所有日期
*
* @param refDate
* 参考日期
* @param weekOffset
* -1:上周 0:本周 1:下周
* @param startDate
* 哪天算一周的第一天
* @return yyyy-MM-dd 格式的日期
* @throws ParseException
* @
*/
public static List<String> getWeekDaysAroundDate(String refDate,
int weekOffset, String startDate) throws ParseException {
// 以startDate为一周的第一天
Calendar c = Calendar.getInstance();
c.setTime(formatStringToDate(startDate, DATE_FORMAT_YMD));
int firstDayOfWeek = c.get(Calendar.DAY_OF_WEEK);
// 获取相应周
int[] weekAndYear = getWeekAndYear(refDate, weekOffset, firstDayOfWeek);
// 获取相应周的所有日期
return getWeekDays(weekAndYear[1], weekAndYear[0], firstDayOfWeek);
}
/**
* 根据时间点获取时间区间
*
* @param hours
* @return
*/
public static List<String[]> getTimePointsByHour(int[] hours) {
List<String[]> hourPoints = new ArrayList<String[]>();
String sbStart = ":00:00";
String sbEnd = ":59:59";
for (int i = 0; i < hours.length; i++) {
String[] times = new String[2];
times[0] = hours[i] + sbStart;
times[1] = (hours[(i + 1 + hours.length) % hours.length] - 1)
+ sbEnd;
hourPoints.add(times);
}
return hourPoints;
}
/**
*
* 根据指定的日期，增加或者减少天数
*
* @param date
* @param amount
* @return
*/
public static Date addDays(Date date, int amount) {
return add(date, Calendar.DAY_OF_MONTH, amount);
}
/**
* 根据指定的日期，类型，增加或减少数量
*
* @param date
* @param calendarField
* @param amount
* @return
*/
public static Date add(Date date, int calendarField, int amount) {
if (date == null) {
throw new IllegalArgumentException("The date must not be null");
}
Calendar c = Calendar.getInstance();
c.setTime(date);
c.add(calendarField, amount);
return c.getTime();
}
/**
* 获取当前日期的最大日期 时间2014-12-21 23:59:59
* @return
*/
public static Date getCurDateWithMaxTime() {
Calendar c = Calendar.getInstance();
c.set(Calendar.HOUR_OF_DAY, 23);
c.set(Calendar.MINUTE, 59);
c.set(Calendar.SECOND, 59);
return c.getTime();
}
/**
* 获取当前日期的最小日期时间 2014-12-21 00:00:00
* @return
*/
public static Date getCurDateWithMinTime() {
Calendar c = Calendar.getInstance();
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
return c.getTime();
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。