基于Java8的日期时间工具类DateTimeFormatter
原文:https://blog.csdn.net/qq_36596145/article/details/85331002
import java.time.Instant; import java.time.LocalDate; import java.time.LocalDateTime; import java.time.LocalTime; import java.time.ZoneId; import java.time.ZonedDateTime; import java.time.format.DateTimeFormatter; import java.time.temporal.ChronoField; import java.util.Date; /** * 基于Java8的时间工具类 * * @author keji * @version $Id: DateUtil.java, v 0.1 2018-12-28 14:11 keji Exp $ */ public class DateUtil { /** * 例如:2018-12-28 */ public static final String DATE = "yyyy-MM-dd"; /** * 例如:2018-12-28 10:00:00 */ public static final String DATE_TIME = "yyyy-MM-dd HH:mm:ss"; /** * 例如:10:00:00 */ public static final String TIME = "HHmmss"; /** * 例如:10:00 */ public static final String TIME_WITHOUT_SECOND = "HH:mm"; /** * 例如:2018-12-28 10:00 */ public static final String DATE_TIME_WITHOUT_SECONDS = "yyyy-MM-dd HH:mm"; /** * 获取年 * * @return 年 */ public static int getYear() { LocalTime localTime = LocalTime.now(); return localTime.get(ChronoField.YEAR); } /** * 获取月份 * * @return 月份 */ public static int getMonth() { LocalTime localTime = LocalTime.now(); return localTime.get(ChronoField.MONTH_OF_YEAR); } /** * 获取某月的第几天 * * @return 几号 */ public static int getMonthOfDay() { LocalTime localTime = LocalTime.now(); return localTime.get(ChronoField.DAY_OF_MONTH); } /** * 格式化日期为字符串 * * @param date date * @param pattern 格式 * @return 日期字符串 */ public static String format(Date date,String pattern){ Instant instant = date.toInstant(); LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault()); return localDateTime.format(DateTimeFormatter.ofPattern(pattern)); } /** * 解析字符串日期为Date * * @param dateStr 日期字符串 * @param pattern 格式 * @return Date */ public static Date parse(String dateStr, String pattern) { LocalDateTime localDateTime = LocalDateTime.parse(dateStr, DateTimeFormatter.ofPattern(pattern)); Instant instant = localDateTime.atZone(ZoneId.systemDefault()).toInstant(); return Date.from(instant); } /** * 为Date增加分钟,减传负数 * * @param date 日期 * @param plusMinutes 要增加的分钟数 * @return 新的日期 */ public static Date addMinutes(Date date, Long plusMinutes) { LocalDateTime dateTime = LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault()); LocalDateTime newDateTime = dateTime.plusMinutes(plusMinutes); return Date.from(newDateTime.atZone(ZoneId.systemDefault()).toInstant()); } /** * 增加时间 * * @param date date * @param hour 要增加的小时数 * @return new date */ public static Date addHour(Date date, Long hour) { LocalDateTime dateTime = LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault()); LocalDateTime localDateTime = dateTime.plusHours(hour); return Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant()); } /** * @return 返回当天的起始时间 */ public static Date getStartTime() { LocalDateTime now = LocalDateTime.now().withHour(0).withMinute(0).withSecond(0); return localDateTime2Date(now); } /** * @return 返回当天的结束时间 */ public static Date getEndTime() { LocalDateTime now = LocalDateTime.now().withHour(23).withMinute(59).withSecond(59).withNano(999); return localDateTime2Date(now); } /** * 减月份 * * @param monthsToSubtract 月份 * @return Date */ public static Date minusMonths(long monthsToSubtract){ LocalDate localDate = LocalDate.now().minusMonths(monthsToSubtract); return localDate2Date(localDate); } /** * LocalDate类型转为Date * * @param localDate LocalDate object * @return Date object */ public static Date localDate2Date(LocalDate localDate) { ZonedDateTime zonedDateTime = localDate.atStartOfDay(ZoneId.systemDefault()); return Date.from(zonedDateTime.toInstant()); } /** * LocalDateTime类型转为Date * * @param localDateTime LocalDateTime object * @return Date object */ public static Date localDateTime2Date(LocalDateTime localDateTime) { return Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant()); } /** * 查询当前年的第一天 * * @param pattern 格式,默认格式yyyyMMdd * @return 20190101 */ public static String getFirstDayOfCurrentYear(String pattern) { LocalDateTime localDateTime = LocalDateTime.now().withMonth(1).withDayOfMonth(1); if (StringUtils.isEmpty(pattern)) { pattern = "yyyyMMdd"; } return format(localDateTime2Date(localDateTime), pattern); } /** * 查询前一年最后一个月第一天 * * @param pattern 格式,默认格式yyyyMMdd * @return 20190101 */ public static String getLastMonthFirstDayOfPreviousYear(String pattern) { LocalDateTime localDateTime = LocalDateTime.now().minusYears(1L).withMonth(12).withDayOfMonth(1); if (StringUtils.isEmpty(pattern)) { pattern = "yyyyMMdd"; } return format(localDateTime2Date(localDateTime), pattern); } /** * 查询前一年最后一个月第一天 * * @param pattern 格式,默认格式yyyyMMdd * @return 20190101 */ public static String getLastMonthLastDayOfPreviousYear(String pattern) { LocalDateTime localDateTime = LocalDateTime.now().minusYears(1L).with(TemporalAdjusters.lastDayOfYear()); if (StringUtils.isEmpty(pattern)) { pattern = "yyyyMMdd"; } return format(localDateTime2Date(localDateTime), pattern); } /** * 获取当前日期 * * @param pattern 格式,默认格式yyyyMMdd * @return 20190101 */ public static String getCurrentDay(String pattern) { LocalDateTime localDateTime = LocalDateTime.now(); if (StringUtils.isEmpty(pattern)) { pattern = "yyyyMMdd"; } return format(localDateTime2Date(localDateTime), pattern); } }
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