JDK 8 新特性-时间日期

系统管理员 2023-07-03 02:59 18阅读 0赞

**目录**

1、LocalDateTime

2、LocalDate

3、LocalTime

--------------------

从Java8开始，推出了LocalDate、LocalTime、LocalDateTime这三个时间工具类，实现了更好地时间处理。LocalDate、LocalTime、LocalDateTime类的实例是不可变的对象，分别表示使用ISO-8601日历系统的日期、时间、日期和时间。它们提供了简单的日期或时间，并不包含当前的时间信息。也不包含与时区相关的信息。

## **1、LocalDateTime** ##

java.time.LocalDateTime类表示ISO-8601日历系统中没有时区的日期时间。下面是常用的方法：

<table> 
 <tbody> 
  <tr> 
   <th>方法</th> 
   <th>说明</th> 
  </tr> 
  <tr> 
   <td>LocalDateTime.now()</td> 
   <td>从默认时区的系统时钟获取当前的日期时间。</td> 
  </tr> 
  <tr> 
   <td>public static LocalDateTime of(int year,Month month,int dayOfMonth,int hour,int minute,int second)</td> 
   <td>从年，月，日，小时，分钟和秒获得<code>LocalDateTime</code>的实例，将纳秒设置为零。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.getYear()</td> 
   <td>获取年份字段。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.getMonth()</td> 
   <td>使用<code>Month</code>枚举获取月份字段。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.getMonthValue()</td> 
   <td>获取<code>1</code>到<code>12</code>之间的月份字段。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.getHour()</td> 
   <td>获取小时字段。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.getMinute()</td> 
   <td>获取分钟字段。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.getSecond()</td> 
   <td>获取秒字段。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.getDayOfYear()</td> 
   <td>获取当前日期是所在年的第几天</td> 
  </tr> 
  <tr> 
   <td>localDateTime.getDayOfMonth()</td> 
   <td>获取当前日期月份中的第几天，从<code>1</code>到<code>31</code>。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.getDayOfWeek()</td> 
   <td>获取星期几字段，即枚举<code>DayOfWeek</code>。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.plusYears(long years)</td> 
   <td>将当前日期加years年</td> 
  </tr> 
  <tr> 
   <td>localDateTime.plusMonths(long months)</td> 
   <td>将当前日期加months月</td> 
  </tr> 
  <tr> 
   <td>localDateTime.plusWeeks(long weeks)</td> 
   <td>将当前日期加weeks周</td> 
  </tr> 
  <tr> 
   <td>localDateTime.plusDays(long days)</td> 
   <td>将当前日期加days天</td> 
  </tr> 
  <tr> 
   <td>localDateTime.plusHours(long hours)</td> 
   <td>将当前日期加hours小时</td> 
  </tr> 
  <tr> 
   <td>localDateTime.plusMinutes(long minutes)</td> 
   <td>将当前日期加minutes分钟</td> 
  </tr> 
  <tr> 
   <td>localDateTime.plusSeconds(long seconds)</td> 
   <td>将当前日期加seconds秒</td> 
  </tr> 
  <tr> 
   <td>localDateTime.minusYears(long years)</td> 
   <td>将当前日期减years年</td> 
  </tr> 
  <tr> 
   <td>localDateTime.minusMonths(long months)</td> 
   <td>将当前日期减months月</td> 
  </tr> 
  <tr> 
   <td>localDateTime.minusWeeks(long weeks)</td> 
   <td>将当前日期减weeks周</td> 
  </tr> 
  <tr> 
   <td>localDateTime.minusDays(long days)</td> 
   <td>将当前日期减days天</td> 
  </tr> 
  <tr> 
   <td>localDateTime.minusHours(long hours)</td> 
   <td>将当前日期减hours小时</td> 
  </tr> 
  <tr> 
   <td>localDateTime.minusMinutes(long minutes)</td> 
   <td>将当前日期减minutes分钟</td> 
  </tr> 
  <tr> 
   <td>localDateTime.minusSeconds(long seconds)</td> 
   <td>将当前日期减seconds秒</td> 
  </tr> 
  <tr> 
   <td>localDateTime.minus(long amountToSubtract, TemporalUnit unit)</td> 
   <td>减去指定的时间。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.format(DateTimeFormatter formatter)</td> 
   <td>使用指定的格式化程序格式化此日期时间。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.isAfter(ChronoLocalDateTime other)</td> 
   <td>检查这个日期时间是否在指定的日期之后。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.isBefore(ChronoLocalDateTime other)</td> 
   <td>检查此日期时间是否在指定的日期时间之前。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.compareTo(ChronoLocalDateTime other)</td> 
   <td>将此日期时间与其他日期时间进行比较。</td> 
  </tr> 
  <tr> 
   <td>localDateTime.withDayOfYear(int dayOfYear)</td> 
   <td>返回LocalDateTime年的第几天更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDateTime.withDayOfMonth(int dayOfMonth)</td> 
   <td>返回LocalDateTime月的第几天更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDateTime.withYear(int year)</td> 
   <td>返回LocalDateTime年份更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDateTime.withMonth(int month)</td> 
   <td>返回LocalDateTime的月份更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDateTime.withHour(int hour)</td> 
   <td>返回LocalDateTime的小时数更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDateTime.withMinute(int minute)</td> 
   <td>返回LocalDateTime的分钟数更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDateTime.withSecond(int second)</td> 
   <td>返回LocalDateTime的秒数更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDateTime.withNano(int nanoOfSecond)</td> 
   <td>返回LocalDateTime的纳秒数更改为新值后的副本</td> 
  </tr> 
 </tbody> 
</table>

代码示例：

public class TimeExample01 {
        public static void main(String[] args) {
            // 获取当前时间
            LocalDateTime localDateTime = LocalDateTime.now();
            System.out.println(localDateTime);
            // 获取指定时间
            LocalDateTime of = LocalDateTime.of(2020,02,01,11,01,01);
            System.out.println(of);
    
            System.out.println("getYear(): " + localDateTime.getYear());
            System.out.println("getDayOfYear(): " + localDateTime.getDayOfYear());
            System.out.println("getMonth(): " + localDateTime.getMonth());
            System.out.println("getMonthValue(): " + localDateTime.getMonthValue());
            System.out.println("getDayOfMonth(): " + localDateTime.getDayOfMonth());
            System.out.println("getDayOfWeek(): " + localDateTime.getDayOfWeek());
            System.out.println("getHour(): " + localDateTime.getHour());
            System.out.println("getMinute(): " + localDateTime.getMinute());
            System.out.println("getSecond(): " + localDateTime.getSecond());
            System.out.println("getNano(): " + localDateTime.getNano());
    
            // 时间计算
            System.out.println("plusYears(): " + localDateTime.plusYears(1));
            System.out.println("plusMonths(): " + localDateTime.plusMonths(1));
            System.out.println("plusWeeks(): " + localDateTime.plusWeeks(1));
            System.out.println("plusDays(): " + localDateTime.plusDays(1));
            System.out.println("plusHours(): " + localDateTime.plusHours(1));
            System.out.println("minusYears(): " + localDateTime.minusYears(1));
            System.out.println("minusMonths(): " + localDateTime.minusMonths(1));
            System.out.println("minusWeeks(): " + localDateTime.minusWeeks(1));
            System.out.println("minusDays(): " + localDateTime.minusDays(1));
            System.out.println("minusMinutes(): " + localDateTime.minusMinutes(1));
    
            //格式化时间
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern("YYYY-MM-dd HH:mm:ss");
            System.out.println("format(): " + localDateTime.format(formatter));
    
            //比较时间
            LocalDateTime plusDays = LocalDateTime.now().plusDays(1);
            System.out.println("isAfter(): " + localDateTime.isAfter(plusDays));
            System.out.println("isBefore(): " + localDateTime.isBefore(plusDays));
            System.out.println("compareTo(): " + localDateTime.compareTo(plusDays));
    
        }
    }

运行结果：

2020-02-01T12:17:58.264
    2020-02-01T11:01:01
    getYear(): 2020
    getDayOfYear(): 32
    getMonth(): FEBRUARY
    getMonthValue(): 2
    getDayOfMonth(): 1
    getDayOfWeek(): SATURDAY
    getHour(): 12
    getMinute(): 17
    getSecond(): 58
    getNano(): 264000000
    plusYears(): 2021-02-01T12:17:58.264
    plusMonths(): 2020-03-01T12:17:58.264
    plusWeeks(): 2020-02-08T12:17:58.264
    plusDays(): 2020-02-02T12:17:58.264
    plusHours(): 2020-02-01T13:17:58.264
    minusYears(): 2019-02-01T12:17:58.264
    minusMonths(): 2020-01-01T12:17:58.264
    minusWeeks(): 2020-01-25T12:17:58.264
    minusDays(): 2020-01-31T12:17:58.264
    minusMinutes(): 2020-02-01T12:16:58.264
    format(): 2020-02-01 12:17:58
    isAfter(): false
    isBefore(): true
    compareTo(): -1

## 2、LocalDate ##

<table> 
 <thead> 
  <tr> 
   <th>方法</th> 
   <th>说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>LocalDate.now()</td> 
   <td>从默认时区的系统时钟获取当前的日期时间。</td> 
  </tr> 
  <tr> 
   <td>LocalDate.of(int year,Month month,int dayOfMonth)</td> 
   <td>从年，月，日，获得LocalDate的实例。</td> 
  </tr> 
  <tr> 
   <td>localDate.getYear()</td> 
   <td>获取年份字段。</td> 
  </tr> 
  <tr> 
   <td>localDate.getMonth()</td> 
   <td>使用<code>Month</code>枚举获取月份字段。</td> 
  </tr> 
  <tr> 
   <td>localDate.getMonthValue()</td> 
   <td>获取<code>1</code>到<code>12</code>之间的月份字段。</td> 
  </tr> 
  <tr> 
   <td>localDate.lengthOfMonth()</td> 
   <td>获取当前日期所在月份有多少天</td> 
  </tr> 
  <tr> 
   <td>localDate.getDayOfYear()</td> 
   <td>获取当前日期是所在年的第几天</td> 
  </tr> 
  <tr> 
   <td>localDate.getDayOfMonth()</td> 
   <td>获取当前日期是月份中的第几天，从<code>1</code>到<code>31</code>。</td> 
  </tr> 
  <tr> 
   <td>localDate.getDayOfWeek()</td> 
   <td>获取星期几字段，即枚举<code>DayOfWeek</code>。</td> 
  </tr> 
  <tr> 
   <td>localDate.lengthOfYear()</td> 
   <td>获取当前日期所在年有多少天</td> 
  </tr> 
  <tr> 
   <td>localDate.isLeapYear()</td> 
   <td>获取当前日期所在年是否是闰年</td> 
  </tr> 
  <tr> 
   <td>localDate.plusYears(long years)</td> 
   <td>将当前日期加years年</td> 
  </tr> 
  <tr> 
   <td>localDate.plusMonths(long months)</td> 
   <td>将当前日期加months月</td> 
  </tr> 
  <tr> 
   <td>localDate.plusWeeks(long weeks)</td> 
   <td>将当前日期加weeks周</td> 
  </tr> 
  <tr> 
   <td>localDate.plusDays(long days)</td> 
   <td>将当前日期加days天</td> 
  </tr> 
  <tr> 
   <td>localDate.minusYears(long years)</td> 
   <td>将当前日期减years年</td> 
  </tr> 
  <tr> 
   <td>localDate.minusMonths(long months)</td> 
   <td>将当前日期减months月</td> 
  </tr> 
  <tr> 
   <td>localDate.minusWeeks(long weeks)</td> 
   <td>将当前日期减weeks周</td> 
  </tr> 
  <tr> 
   <td>localDate.minusDays(long days)</td> 
   <td>将当前日期减days天</td> 
  </tr> 
  <tr> 
   <td>localDate.minus(long amountToSubtract, TemporalUnit unit)</td> 
   <td>减去指定的时间。</td> 
  </tr> 
  <tr> 
   <td>localDate.format(DateTimeFormatter formatter)</td> 
   <td>使用指定的格式化程序格式化此日期时间。</td> 
  </tr> 
  <tr> 
   <td>localDate.isAfter(ChronoLocalDateTime other)</td> 
   <td>检查这个日期时间是否在指定的日期之后。</td> 
  </tr> 
  <tr> 
   <td>localDate.isBefore(ChronoLocalDateTime other)</td> 
   <td>检查此日期时间是否在指定的日期时间之前。</td> 
  </tr> 
  <tr> 
   <td>localDate.compareTo(ChronoLocalDateTime other)</td> 
   <td>将此日期时间与其他日期时间进行比较。</td> 
  </tr> 
  <tr> 
   <td>localDate.withDayOfYear(int dayOfYear)</td> 
   <td>返回localDate年的第几天更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDate.withDayOfMonth(int dayOfMonth)</td> 
   <td>返回localDate月的第几天更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDate.withYear(int year)</td> 
   <td>返回localDate年份更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>localDate.withMonth(int month)</td> 
   <td>返回localDate的月份更改为新值后的副本</td> 
  </tr> 
 </tbody> 
</table>

public class TimeExample02 {
        public static void main(String[] args) {
            // 获取当前时间
            LocalDate localDate = LocalDate.now();
            System.out.println(localDate);
            // 获取指定时间
            LocalDate of = LocalDate.of(2020,02,01);
            System.out.println(of);
    
            System.out.println("getYear(): " + localDate.getYear());
            System.out.println("getMonth(): " + localDate.getMonth());
            System.out.println("getMonthValue(): " + localDate.getMonthValue());
            System.out.println("getDayOfYear(): " + localDate.getDayOfYear());
            System.out.println("getDayOfMonth(): " + localDate.getDayOfMonth());
            System.out.println("getDayOfWeek(): " + localDate.getDayOfWeek());
            System.out.println("lengthOfMonth(): " + localDate.lengthOfMonth());
            System.out.println("lengthOfYear(): " + localDate.lengthOfYear());
            System.out.println("isLeapYear(): " + localDate.isLeapYear());
    
            // 时间计算
            System.out.println("plusYears(): " + localDate.plusYears(1));
            System.out.println("plusMonths(): " + localDate.plusMonths(1));
            System.out.println("plusWeeks(): " + localDate.plusWeeks(1));
            System.out.println("plusDays(): " + localDate.plusDays(1));
            System.out.println("minusYears(): " + localDate.minusYears(1));
            System.out.println("minusMonths(): " + localDate.minusMonths(1));
            System.out.println("minusWeeks(): " + localDate.minusWeeks(1));
            System.out.println("minusDays(): " + localDate.minusDays(1));
    
            //格式化时间
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern("YYYY-MM-dd");
            System.out.println("format(): " + localDate.format(formatter));
    
            //比较时间
            LocalDate plusDays = LocalDate.now().plusDays(1);
            System.out.println("isAfter(): " + localDate.isAfter(plusDays));
            System.out.println("isBefore(): " + localDate.isBefore(plusDays));
            System.out.println("compareTo(): " + localDate.compareTo(plusDays));
        }
    }

输出结果：

2020-02-01
    2020-02-01
    getYear(): 2020
    getMonth(): FEBRUARY
    getMonthValue(): 2
    getDayOfYear(): 32
    getDayOfMonth(): 1
    getDayOfWeek(): SATURDAY
    lengthOfMonth(): 29
    lengthOfYear(): 366
    isLeapYear(): true
    plusYears(): 2021-02-01
    plusMonths(): 2020-03-01
    plusWeeks(): 2020-02-08
    plusDays(): 2020-02-02
    minusYears(): 2019-02-01
    minusMonths(): 2020-01-01
    minusWeeks(): 2020-01-25
    minusDays(): 2020-01-31
    format(): 2020-02-01
    isAfter(): false
    isBefore(): true
    compareTo(): -1

## 3、LocalTime ##

<table> 
 <thead> 
  <tr> 
   <th>方法</th> 
   <th>说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>LocalTime.now()</td> 
   <td>从默认时区的系统时钟获取当前的日期时间。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.of(int hour,int minute,int second)</td> 
   <td>从小时，分钟和秒获得LocalTime的实例，将纳秒设置为零。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.getHour()</td> 
   <td>获取小时字段。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.getMinute()</td> 
   <td>获取分钟字段。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.getSecond()</td> 
   <td>获取秒字段。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.plusHours(long hours)</td> 
   <td>将当前日期加hours小时</td> 
  </tr> 
  <tr> 
   <td>LocalTime.plusMinutes(long minutes)</td> 
   <td>将当前日期加minutes分钟</td> 
  </tr> 
  <tr> 
   <td>LocalTime.plusSeconds(long seconds)</td> 
   <td>将当前日期加seconds秒</td> 
  </tr> 
  <tr> 
   <td>LocalTime.minusHours(long hours)</td> 
   <td>将当前日期减hours小时</td> 
  </tr> 
  <tr> 
   <td>LocalTime.minusMinutes(long minutes)</td> 
   <td>将当前日期减minutes分钟</td> 
  </tr> 
  <tr> 
   <td>LocalTime.minusSeconds(long seconds)</td> 
   <td>将当前日期减seconds秒</td> 
  </tr> 
  <tr> 
   <td>LocalTime.minus(long amountToSubtract, TemporalUnit unit)</td> 
   <td>减去指定的时间。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.format(DateTimeFormatter formatter)</td> 
   <td>使用指定的格式化程序格式化此日期时间。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.isAfter(ChronoLocalDateTime other)</td> 
   <td>检查这个日期时间是否在指定的日期之后。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.isBefore(ChronoLocalDateTime other)</td> 
   <td>检查此日期时间是否在指定的日期时间之前。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.compareTo(ChronoLocalDateTime other)</td> 
   <td>将此日期时间与其他日期时间进行比较。</td> 
  </tr> 
  <tr> 
   <td>LocalTime.withHour(int hour)</td> 
   <td>返回LocalTime的小时数更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>LocalTime.withMinute(int minute)</td> 
   <td>返回LocalTime的分钟数更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>LocalTime.withSecond(int second)</td> 
   <td>返回LocalTime的秒数更改为新值后的副本</td> 
  </tr> 
  <tr> 
   <td>LocalTime.withNano(int nanoOfSecond)</td> 
   <td>返回LocalTime的纳秒数更改为新值后的副本</td> 
  </tr> 
 </tbody> 
</table>

public class TimeExample03 {
        public static void main(String[] args) {
            // 获取当前时间
            LocalTime localTime = LocalTime.now();
            System.out.println(localTime);
            // 获取指定时间
            LocalTime of = LocalTime.of(11,01,01);
            System.out.println(of);
    
            System.out.println("getHour(): " + localTime.getHour());
            System.out.println("getMinute(): " + localTime.getMinute());
            System.out.println("getSecond(): " + localTime.getSecond());
            System.out.println("getNano(): " + localTime.getNano());
    
            // 时间计算
            System.out.println("plusHours(): " + localTime.plusHours(1));
            System.out.println("plusMinutes(): " + localTime.plusMinutes(1));
            System.out.println("plusSeconds(): " + localTime.plusSeconds(1));
            System.out.println("plusNanos(): " + localTime.plusNanos(1));
            System.out.println("minusHours(): " + localTime.minusHours(1));
            System.out.println("minusMinutes(): " + localTime.minusMinutes(1));
            System.out.println("minusSeconds(): " + localTime.minusSeconds(1));
            System.out.println("minusNanos(): " + localTime.minusNanos(1));
    
            //格式化时间
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern("HH:mm:ss");
            System.out.println("format(): " + localTime.format(formatter));
    
            //比较时间
            LocalTime plusDays = LocalTime.now().plusHours(1);
            System.out.println("isAfter(): " + localTime.isAfter(plusDays));
            System.out.println("isBefore(): " + localTime.isBefore(plusDays));
            System.out.println("compareTo(): " + localTime.compareTo(plusDays));
        }
    }

运行结果：

13:02:16.607
    11:01:01
    getHour(): 13
    getMinute(): 2
    getSecond(): 16
    getNano(): 607000000
    plusHours(): 14:02:16.607
    plusMinutes(): 13:03:16.607
    plusSeconds(): 13:02:17.607
    plusNanos(): 13:02:16.607000001
    minusHours(): 12:02:16.607
    minusMinutes(): 13:01:16.607
    minusSeconds(): 13:02:15.607
    minusNanos(): 13:02:16.606999999
    format(): 13:02:16
    isAfter(): false
    isBefore(): true
    compareTo(): -1