SimpleDateFormat 你还在用？赶快尝试一下JDK1.8的LocalDateTime、LocalDate...(内有1.8的时间工具类)

it2022-05-05 141

日常开发中，我们经常需要使用时间相关类，想必大家对SimpleDateFormat并不陌生。主要用它进行时间的格式化输出和解析，挺方便快捷的，但是SimpleDateFormat并不是一个线程安全的类。在多线程情况下，会出现异常，想必有经验的小伙伴也遇到过。

接下来看看《阿里巴巴开发手册》对SimpleDateFormat是怎么看待的？

【强制】SimpleDateFormat是线程不安全的类，一般不要定义位static变量，如果定义为static，必须加锁，或者使用DateUtils工具类。正例：注意线程安全，使用DateUtils。亦推荐如下处理 private static final ThreadLocal<DateFormat> df = new ThreadLocal<DateFormat>(){ @Override protected DateFormat initialValue(){ return new SimpleDateFormat("yyyy-MM-dd"); } }; 说明:如果是JDK8的应用，可以使用Instant代替Date，LocalDateTime代替Calendar,DateTimeFormatter 代替SimpleDateFormat，官方给出解释：simple beautiful strong immutable thread-safe

JDK8 DateUtils

个人总结：

import java.time.*; import java.time.format.DateTimeFormatter; import java.time.temporal.ChronoUnit; import java.time.temporal.TemporalAdjusters; import java.util.Date; /** * @ClassName DateUtils * @Description 时间工具类 1.8版本 * @Author QiMing * @Date 2019/4/30 8:45 * @Version 1.0 */ public class DateUtils { /** * 缺省的日期显示格式： yyyy-MM-dd */ public static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd"; /** * 用做单号 */ public static final String DEFAULT_DATE_FORMAT_ORDER = "yyyyMMdd"; /** * 缺省的日期显示格式： yyyy-MM */ public static final String DEFAULT_YYMM_FORMAT = "yyyy-MM"; /** * 缺省的日期时间显示格式：yyyy-MM-dd HH:mm:ss */ public static final String DEFAULT_DATETIME_FORMAT = "yyyy-MM-dd HH:mm:ss"; /** * 缺省的日期时间显示格式：yyyy-MM-dd HH:mm:ss:sss */ public static final String YMDHMSS = "yyyy-MM-dd HH:mm:ss:sss"; /** * 字符串时间 */ public static final String YMDHMS = "yyyyMMddHHmmss"; /** * 当前时间 */ public static Date DATE_NOW = new Date(); /** * 当前时间 */ public static LocalDate localDate = LocalDate.now(); /** * @Title getDay * @Description 获取年月日（当天） * @Param [] * @Return java.lang.String * @Date 2019/6/4 15:26 * @Author QiMing */ public static String getDay() { LocalDate date = LocalDate.now(); DateTimeFormatter fmt = DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT); return date.format(fmt); } /** * @Title getDayTime * @Description 年月日时分秒（当天）此方法不支持毫秒 * @Param [] * @Return java.lang.String * @Date 2019/6/4 15:28 * @Author QiMing */ public static String getDayTime() { LocalDateTime date = LocalDateTime.now(); DateTimeFormatter fmt = DateTimeFormatter.ofPattern(DEFAULT_DATETIME_FORMAT); return date.format(fmt); } /** * @Title getDateToString * @Description date类型转换字符串 * @Param [date] * @Return java.lang.String * @Date 2019/7/8 11:07 * @Author QiMing */ public static String getDateToString(Date date) { LocalDateTime localDateTime = date.toInstant().atZone(ZoneId.systemDefault()).toLocalDateTime(); DateTimeFormatter fmt = DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT_ORDER); return localDateTime.format(fmt); } /** * @Title getLocalDateToString * @Description LocalDate转换String * @Param [localDate] * @Return java.lang.String * @Date 2019/7/8 11:10 * @Author QiMing */ public static String getLocalDateToString(LocalDate localDate) { DateTimeFormatter fmt = DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT_ORDER); return localDate.format(fmt); } /** * @Title getFixedTime * @Description 自定固定时间 * @Param [year, month, day, hour, minute, second] * @Return java.time.LocalDateTime * @Date 2019/7/8 15:23 * @Author QiMing */ public static LocalDateTime getFixedTime(int year, int month, int day, int hour, int minute, int second) { return LocalDateTime.of(year, month, day, hour, minute, second); } /** * @Title settingsTime * @Description 设置固定时间 * @Param [year, month, day, hour, minute, second] * @Return java.time.LocalDateTime * @Date 2019/7/8 15:29 * @Author QiMing */ public static LocalDateTime settingsTime(int year, int month, int day, int hour, int minute, int second) { return LocalDateTime.now().withYear(year).withMonth(month).withDayOfMonth(day).withHour(hour).withMinute(minute).withSecond(second); } /** * @Title firstToMonth * @Description 当月第一天 * @Param [] * @Return java.time.LocalDate * @Date 2019/7/8 15:31 * @Author QiMing */ public static LocalDate firstToMonth() { return localDate.with(TemporalAdjusters.firstDayOfMonth()); } /** * @Title lastToMonth * @Description 本月最后一天 * @Param [] * @Return java.time.LocalDate * @Date 2019/7/8 15:33 * @Author QiMing */ public static LocalDate lastToMonth() { return localDate.with(TemporalAdjusters.lastDayOfMonth()); } /** * @Title firstNextMonth * @Description 下个月第一天 * @Param [] * @Return java.time.LocalDate * @Date 2019/7/8 15:35 * @Author QiMing */ public static LocalDate firstNextMonth() { return localDate.with(TemporalAdjusters.firstDayOfNextMonth()); } /** * @Title firstToYear * @Description 本年第一天 * @Param [] * @Return java.time.LocalDate * @Date 2019/7/8 15:36 * @Author QiMing */ public static LocalDate firstToYear() { return localDate.with(TemporalAdjusters.firstDayOfYear()); } /** * @Title lastToYear * @Description 本年最后一天 * @Param [] * @Return java.time.LocalDate * @Date 2019/7/8 15:37 * @Author QiMing */ public static LocalDate lastToYear() { return localDate.with(TemporalAdjusters.lastDayOfYear()); } /*——————————————————— 时间相差 start ———————————————————————*/ /** * @Title difference * @Description 相差分钟 * @Param [localTime, localTime1] * @Return long * @Date 2019/7/8 15:43 * @Author QiMing */ public static long difference(LocalTime localTime, LocalTime localTime1) { return Duration.between(localTime, localTime1).getSeconds(); } /** * @Title aFewYearsApart * @Description 相差几年 * @Param [oldDate, newDate] * @Return long * @Date 2019/7/8 15:47 * @Author QiMing */ public static long aFewYearsApart(LocalDateTime oldDate, LocalDateTime newDate) { return ChronoUnit.YEARS.between(oldDate, newDate); } /** * @Title aFewMonthsApart * @Description 相差几个月 * @Param [oldDate, newDate] * @Return long * @Date 2019/7/8 15:49 * @Author QiMing */ public static long aFewMonthsApart(LocalDateTime oldDate, LocalDateTime newDate) { return ChronoUnit.MONTHS.between(oldDate, newDate); } /** * @Title aFewWEEKSApart * @Description 相差多少周 * @Param [oldDate, newDate] * @Return long * @Date 2019/7/8 15:50 * @Author QiMing */ public static long aFewWEEKSApart(LocalDateTime oldDate, LocalDateTime newDate) { return ChronoUnit.WEEKS.between(oldDate, newDate); } /** * @Title aFewDAYSApart * @Description 相差多少天 * @Param [oldDate, newDate] * @Return long * @Date 2019/7/8 15:51 * @Author QiMing */ public static long aFewDAYSApart(LocalDateTime oldDate, LocalDateTime newDate) { return ChronoUnit.DAYS.between(oldDate, newDate); } /** * @Title aFewHOURSApart * @Description 相差多少小时 * @Param [oldDate, newDate] * @Return long * @Date 2019/7/8 15:52 * @Author QiMing */ public static long aFewHOURSApart(LocalDateTime oldDate, LocalDateTime newDate) { return ChronoUnit.HOURS.between(oldDate, newDate); } /** * @Title aFewHOURSApart * @Description 相差多少分钟 * @Param [oldDate, newDate] * @Return long * @Date 2019/7/8 15:52 * @Author QiMing */ public static long aFewMINUTESApart(LocalDateTime oldDate, LocalDateTime newDate) { return ChronoUnit.MINUTES.between(oldDate, newDate); } /** * @Title aFewSECONDSApart * @Description 相差多少秒 * @Param [oldDate, newDate] * @Return long * @Date 2019/7/8 15:54 * @Author QiMing */ public static long aFewSECONDSApart(LocalDateTime oldDate, LocalDateTime newDate) { return ChronoUnit.SECONDS.between(oldDate, newDate); } /** * @Title aFewMILLISApart * @Description 相差多少毫秒 * @Param [oldDate, newDate] * @Return long * @Date 2019/7/8 15:55 * @Author QiMing */ public static long aFewMILLISApart(LocalDateTime oldDate, LocalDateTime newDate) { return ChronoUnit.MILLIS.between(oldDate, newDate); } /** * @Title aFewMILLISApart * @Description 相差多少纳秒 * @Param [oldDate, newDate] * @Return long * @Date 2019/7/8 15:55 * @Author QiMing */ public static long aFewNANOSApart(LocalDateTime oldDate, LocalDateTime newDate) { return ChronoUnit.NANOS.between(oldDate, newDate); } /*——————————————————— 时间相差 end ———————————————————————*/ /** * @Title getTimestamp * @Description 获取时间戳13位 * @Param [] * @Return long * @Date 2019/7/8 15:59 * @Author QiMing */ public static long getTimestamp() { return Clock.systemDefaultZone().millis(); } /*——————————————————————— 时间转换 Start ——————————————————————*/ /** * @Title dateToLocalDateTime * @Description date转换LocalDateTime * @Param [date] * @Return java.time.LocalDateTime * @Date 2019/7/8 16:05 * @Author QiMing */ public static LocalDateTime dateToLocalDateTime(Date date) { // LocalDateTime.ofInstant(date.toInstant(),ZoneId.systemDefault()); return date.toInstant().atZone(ZoneId.systemDefault()).toLocalDateTime(); } /** * @Title dateToLocalDate * @Description date转换LocalDate * @Param [date] * @Return java.time.LocalDate * @Date 2019/7/8 16:08 * @Author QiMing */ public static LocalDate dateToLocalDate(Date date) { return date.toInstant().atZone(ZoneId.systemDefault()).toLocalDate(); } /** * @Title dateToLocalTime * @Description date转换LocalTime * @Param [date] * @Return java.time.LocalTime * @Date 2019/7/8 16:08 * @Author QiMing */ public static LocalTime dateToLocalTime(Date date) { return date.toInstant().atZone(ZoneId.systemDefault()).toLocalTime(); } /** * @Title localDateTimeToDate * @Description LocalDateTime转为Date * @Param [localDateTime] * @Return java.util.Date * @Date 2019/7/8 16:10 * @Author QiMing */ public static Date localDateTimeToDate(LocalDateTime localDateTime) { return Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant()); } /** * @Title localDateToDate * @Description LocalDate -> Date，时间默认都是00 * @Param [localDate] * @Return java.util.Date * @Date 2019/7/8 16:13 * @Author QiMing */ public static Date localDateToDate(LocalDate localDate) { return Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant()); } /*——————————————————————— 时间转换 End ——————————————————————*/ /*———————————————————————— 日期与字符串、字符串与时间转换 Start ——————————————————————————*/ /** * @Title stringConversionLocalDate * @Description 字符串转LocalDate * @Param [ymd] * @Return java.time.LocalDate * @Date 2019/7/8 16:19 * @Author QiMing */ public static LocalDate stringConversionLocalDate(String ymd) { return LocalDate.parse(ymd, DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT)); } /** * @Title stringConversionLocalDateTime * @Description 字符串转LocalDateTime * @Param [ymdhms] * @Return java.time.LocalDateTime * @Date 2019/7/8 16:22 * @Author QiMing */ public static LocalDateTime stringConversionLocalDateTime(String ymdhms) { return LocalDateTime.parse(ymdhms, DateTimeFormatter.ofPattern(DEFAULT_DATETIME_FORMAT)); } /** * @Title localDateConversionString * @Description localDate转字符串 * @Param [localDate] * @Return java.lang.String * @Date 2019/7/8 16:24 * @Author QiMing */ public static String localDateConversionString(LocalDate localDate) { return localDate.format(DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT)); } /** * @Title localDateTimeConversionString * @Description localDateTime转字符串 * @Param [localDateTime] * @Return java.lang.String * @Date 2019/7/8 16:25 * @Author QiMing */ public static String localDateTimeConversionString(LocalDateTime localDateTime) { return localDateTime.format(DateTimeFormatter.ofPattern(DEFAULT_DATETIME_FORMAT)); } /** * @Title localDateTimeToString * @Description localDateTime转字符串 * @Param [localDateTime] * @Return java.lang.String * @Date 2019/7/8 16:28 * @Author QiMing */ public static String localDateTimeToString(LocalDateTime localDateTime) { return DateTimeFormatter.ofPattern(DEFAULT_DATETIME_FORMAT).format(localDateTime); } /*———————————————————————— 日期与字符串、字符串与时间转换 end ——————————————————————————*/ /** * @Title timestampConversionLocalDateTime * @Description 时间戳转换Localdatetime * @Param [timeMillis] * @Return java.time.LocalDateTime * @Date 2019/7/8 16:32 * @Author QiMing */ public static LocalDateTime timestampConversionLocalDateTime(long timeMillis) { Instant instant = Instant.ofEpochMilli(timeMillis); return LocalDateTime.ofInstant(instant, ZoneId.systemDefault()); } /** * @Title localDateTimeConversiontimestamp * @Description localDateTime 转换时间戳 * @Param [localDateTime] * @Return long * @Date 2019/7/8 16:34 * @Author QiMing */ public static long localDateTimeConversiontimestamp(LocalDateTime localDateTime) { return localDateTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli(); } /** * @Title getWeek * @Description 获取周几 * @Param [localDate] * @Return java.lang.String * @Date 2019/7/8 17:08 * @Author QiMing */ public static String getWeek(LocalDate localDate) { String week = String.valueOf(localDate.getDayOfWeek()); switch (week) { case "MONDAY": week = "周一"; break; case "TUESDAY": week = "周二"; break; case "WEDNESDAY": week = "周三"; break; case "THURSDAY": week = "周四"; break; case "FRIDAY": week = "周五"; break; case "SATURDAY": week = "周六"; break; case "SUNDAY": week = "周日"; break; } return week; } /** * @Title localDateTimeChangeTen * @Description LocalDateTime转换10位时间戳 * @Param [localDateTime] * @Return long * @Date 2019/7/9 8:39 * @Author QiMing */ public static long localDateTimeChangeTen(LocalDateTime localDateTime) { long lon = localDateTimeConversiontimestamp(localDateTime) / 1000; return Long.valueOf(String.format("0d", lon)); } }

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