Java 8 DateUtility日期实用类

转x33g5p2x  于2022-10-06 转载在 Java  
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在这篇文章中，我们将讨论几个常用的Java 8日期时间实用方法。我们还可以向您展示所有Java 8日期实用方法的样本JUnittest case。

Java 8 Date Utility Class包含了与日期和时间有关的实用方法，您可以在日常的项目工作中使用这些方法。

不要忘记查看我们的Java 8日期时间API教程的成果

Java8 DateUtility类方法

  • getLocalDateFromClock() - 获取当前本地日期。
  • LocalDate getNextDay(LocalDate localDate) - 获得第二天的日期。
  • LocalDate getNextDay(LocalDate localDate) - 获得下一天。
  • LocalDate getPreviousDay(LocalDate localDate) - 获得前一天。
  • DayOfWeek getDayOfWeek(LocalDate localDate) - 获得一周的日子。
  • LocalDate getFirstDayOfMonth() - 获得本月的第一天。
  • LocalDateTime getStartOfDay(LocalDate localDate) - 获得一天的开始。
  • printCurrentDayMonthAndYear() - 以日、月、年的格式打印当前时间。
  • checkDateEquals(LocalDate date, LocalDate today) - 检查两个日期是否相等。
  • LocalTime getCurrentTime() - 获取当前时间。
  • LocalTime addHoursToTime(int hours) - 向时间添加小时。
  • ZonedDateTime timeZone(String timeZone) - 按地区获取日期和时间。
  • checkLeafYear() - 检查叶子的年份。
  • Instant getTimeStamp() - 获得时间戳。
  • LocalTime getLocalTimeUsingFactoryOfMethod(int hour, int min, int seconds)  - 按小时、分钟和秒获取日期。
  • ZonedDateTime getZonedDateTime(LocalDateTime localDateTime, ZoneId zoneId) - 获得区域日期时间。
  • LocalTime modifyDates(LocalTime localTime, Duration duration) - 返回这个时间的副本，并加上指定的数量。
  • Duration getDifferenceBetweenDates(LocalTime localTime1, LocalTime localTime2) - 获得代表两个时间对象之间的持续时间的Duration。
  • LocalDateTime getLocalDateTimeUsingParseMethod(String representation) - 通过传递格式获得日期和时间。
  • LocalDateTime convertDateToLocalDate(Date date) - 将日期转换成Java 8 LocalDate。
  • LocalDateTime convertDateToLocalDate(Calendar calendar) - 将日历转换成LocalDate

Java8DateUtility.java

  1. package com.ramesh.java8.datetime;
  3. import java.time.DayOfWeek;
  4. import java.time.Duration;
  5. import java.time.Instant;
  6. import java.time.LocalDate;
  7. import java.time.LocalDateTime;
  8. import java.time.LocalTime;
  9. import java.time.ZoneId;
  10. import java.time.ZonedDateTime;
  11. import java.time.temporal.ChronoUnit;
  12. import java.time.temporal.TemporalAdjusters;
  13. import java.util.Calendar;
  14. import java.util.Date;
  16. /**
  17. * Useful Java8DateUtiliy Methods
  18. * @author javaguides.net
  19. *
  20. */
  22. public final class Java8DateUtility {
  24.  /**
  25. *  Get current local date.
  26. * @return
  27. */
  28.  public static LocalDate getLocalDateFromClock() {
  29.      return LocalDate.now();
  30.  }
  32.  /**
  33. * Get next day.
  34. * @param localDate
  35. * @return
  36. */
  37.  public static LocalDate getNextDay(LocalDate localDate) {
  38.      return localDate.plusDays(1);
  39.  }
  41.  /**
  42. * Get Previous Day.
  43. * @param localDate
  44. * @return
  45. */
  46.  public static LocalDate getPreviousDay(LocalDate localDate) {
  47.      return localDate.minus(1, ChronoUnit.DAYS);
  48.  }
  50.  /**
  51. * Get day of the week.
  52. * @param localDate
  53. * @return
  54. */
  55.  public static DayOfWeek getDayOfWeek(LocalDate localDate) {
  56.      DayOfWeek day = localDate.getDayOfWeek();
  57.      return day;
  58.  }
  60.  /**
  61. * Get first day of the Month.
  62. * @return LocalDate
  63. */
  64.  public static LocalDate getFirstDayOfMonth() {
  65.      LocalDate firstDayOfMonth = LocalDate.now().with(TemporalAdjusters.firstDayOfMonth());
  66.      return firstDayOfMonth;
  67.  }
  69.  /**
  70. * Get start of the Day.
  71. * @param localDate
  72. * @return
  73. */
  74.  public static LocalDateTime getStartOfDay(LocalDate localDate) {
  75.      LocalDateTime startofDay = localDate.atStartOfDay();
  76.      return startofDay;
  77.  }
  79.  /**
  80. * Print current time in day,month and year format.
  81. */
  82.  public static void printCurrentDayMonthAndYear() {
  83.      LocalDate today = LocalDate.now();
  84.      int year = today.getYear();
  85.      int month = today.getMonthValue();
  86.      int day = today.getDayOfMonth();
  87.      System.out.printf("Year : %d Month : %d day : %d \t %n", year, month, day);
  88.  }
  90.  /**
  91. * Check two dates are equals.
  92. * @param date
  93. * @param today
  94. * @return
  95. */
  96.  public static boolean checkDateEquals(LocalDate date, LocalDate today) {
  97.      if (date.equals(today)) {
  98.         System.out.printf("Today %s and date1 %s are same date %n", today, date);
  99.         return true;
  100.      }
  101.      return false;
  102.  }
  104.  /**
  105. * Get current time.
  106. * @return
  107. */
  108.  public static LocalTime getCurrentTime() {
  109.      LocalTime time = LocalTime.now();
  110.      System.out.println("local time now : " + time);
  111.      return time;
  112.  }
  114.  /**
  115. * Add hours to time.
  116. * @param hours
  117. * @return
  118. */
  119.  public static LocalTime addHoursToTime(int hours) {
  120.      LocalTime time = LocalTime.now();
  121.      LocalTime newTime = time.plusHours(hours); // adding two hours
  122.      System.out.println("Time after 2 hours : " + newTime);
  123.      return newTime;
  124.  }
  126.  /**
  127. * Get date and time by zone.
  128. * @param timeZone
  129. * @return
  130. */
  131.  public static ZonedDateTime timeZone(String timeZone) {
  132.      ZoneId america = ZoneId.of(timeZone);
  133.      LocalDateTime localtDateAndTime = LocalDateTime.now();
  134.      ZonedDateTime dateAndTimeInNewYork = ZonedDateTime.of(localtDateAndTime, america);
  135.      System.out.println("Current date and time in a particular timezone : " + dateAndTimeInNewYork);
  136.      return dateAndTimeInNewYork;
  137.  }
  139.  /**
  140. * Check for leap year.
  141. */
  142.  public static void checkLeapYear() {
  143.      LocalDate today = LocalDate.now();
  144.      if (today.isLeapYear()) {
  145.          System.out.println("This year is Leap year");
  146.      } else {
  147.          System.out.println("2014 is not a Leap year");
  148.      }
  149.  }
  151.  /**
  152. * get time stamp.
  153. * @return
  154. */
  155.  public static Instant getTimeStamp() {
  156.      Instant timestamp = Instant.now();
  157.      System.out.println("What is value of this instant " + timestamp);
  158.      return timestamp;
  159.  }
  161.  /**
  162. * Get Date by hour,minute and seconds.
  163. * @param hour
  164. * @param min
  165. * @param seconds
  166. * @return
  167. */
  168.  public static LocalTime getLocalTimeUsingFactoryOfMethod(int hour, int min, int seconds) {
  169.       return LocalTime.of(hour, min, seconds);
  170.  }
  172.  /**
  173. * Get zone date time.
  174. * @param localDateTime
  175. * @param zoneId
  176. * @return
  177. */
  178.  public static ZonedDateTime getZonedDateTime(LocalDateTime localDateTime, ZoneId zoneId) {
  179.       return ZonedDateTime.of(localDateTime, zoneId);
  180.  }
  182.  /**
  183. * Returns a copy of this time with the specified amount added.
  184. * @param localTime
  185. * @param duration
  186. * @return
  187. */
  188.  public static LocalTime modifyDates(LocalTime localTime, Duration duration) {
  189.       return localTime.plus(duration);
  190.  }
  192.  /**
  193. * Obtains a Duration representing the duration between two temporal objects.
  194. * @param localTime1
  195. * @param localTime2
  196. * @return
  197. */
  198.  public static Duration getDifferenceBetweenDates(LocalTime localTime1, LocalTime localTime2) {
  199.      return Duration.between(localTime1, localTime2);
  200.  }
  202.  /**
  203. * Get date and time by passing format
  204. * @param representation
  205. * @return
  206. */
  207.  public static LocalDateTime getLocalDateTimeUsingParseMethod(String representation) {
  208.      return LocalDateTime.parse(representation);
  209.  }
  211.  /**
  212. * Convert Date to Java 8 LocalDate
  213. * @param date
  214. * @return
  215. */
  216.  public static LocalDateTime convertDateToLocalDate(Date date) {
  217.      return LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault());
  218.  }
  220.  /**
  221. * Convert Calender to LocalDate
  222. * @param calendar
  223. * @return
  224. */
  225.  public static LocalDateTime convertDateToLocalDate(Calendar calendar) {
  226.      return LocalDateTime.ofInstant(calendar.toInstant(), ZoneId.systemDefault());
  227.  }
  228.  
  229. }

Java8DateUtilityTest.java

  1. package com.ramesh.java8.datetime;
  3. import static org.junit.Assert.assertEquals;
  4. import static org.junit.Assert.assertNotNull;
  5. import static org.junit.Assert.assertTrue;
  7. import java.time.LocalDate;
  8. import java.time.LocalDateTime;
  9. import java.time.LocalTime;
  10. import java.time.ZoneId;
  11. import java.time.format.DateTimeFormatter;
  12. import java.util.Calendar;
  13. import java.util.Date;
  15. import org.junit.Test;
  17. /**
  18. * JUnit test cases for Java8DateUtiliy Methods
  19. * @author javaguides.net
  20. *
  21. */
  22. public class Java8DateUtilityTest {
  23.  
  24.  @Test
  25.  public void getLocalDateFromClockTest() {
  26.      System.out.println("Current date ::" +Java8DateUtility.getLocalDateFromClock());
  27.      assertEquals(LocalDate.now(), Java8DateUtility.getLocalDateFromClock());
  28.  }
  30.  @Test
  31.  public void getNextDayTest() {
  32.      LocalDate date = Java8DateUtility.getNextDay(LocalDate.now());
  33.      System.out.println("Next Day ::" + date);
  34.      assertNotNull(date);
  35.  }
  37.  @Test
  38.  public void getPreviousDayTest() {
  39.      System.out.println("Get Previous Day :: " + Java8DateUtility.getPreviousDay(LocalDate.now()));
  40.  }
  41.  
  42.  @Test
  43.  public void getDayOfWeekTest() {
  44.      System.out.println("Get Day Of Week :: " + Java8DateUtility.getDayOfWeek(LocalDate.now()));
  45.  }
  47.  @Test
  48.  public void getFirstDayOfMonthTest() {
  49.      System.out.println("Get First day of Month :: " + Java8DateUtility.getFirstDayOfMonth());
  50.  }
  52.  @Test
  53.  public void getStartOfDayTest() {
  54.      System.out.println("Get start of day :: " + Java8DateUtility.getStartOfDay(LocalDate.now()) );
  55.  }
  57.  @Test
  58.  public void printCurrentDayMonthAndYearTest() {
  59.      Java8DateUtility.printCurrentDayMonthAndYear();
  60.  }
  62.  @Test
  63.  public void checkDateEqualsTest() {
  64.      assertTrue(Java8DateUtility.checkDateEquals(LocalDate.now(), LocalDate.now()));
  65.  }
  67.  @Test
  68.  public void getCurrentTime() {
  69.      assertEquals(Java8DateUtility.getCurrentTime(), LocalTime.now());
  70.  }
  72.  @Test
  73.  public void addHoursToTime() {
  74.      System.out.println("Added hours to time :: " + Java8DateUtility.addHoursToTime(1));
  75.  }
  77.  @Test
  78.  public void timeZoneTest() {
  79.      System.out.println("America/Los_Angeles Zone :: " + Java8DateUtility.timeZone("America/Los_Angeles"));
  80.  }
  82.  @Test
  83.  public void checkLeafYear() {
  84.      Java8DateUtility.checkLeafYear();
  85.  }
  87.  @Test
  88.  public void getTimeStamp() {
  89.      System.out.println("get time stamp ::" + Java8DateUtility.getTimeStamp());
  90.  }
  92.  @Test
  93.  public void getZonedDateTime() {
  94.      System.out.println("" + Java8DateUtility.getZonedDateTime(LocalDateTime.now(), ZoneId.of("Europe/Paris")));
  95.  }
  97.  @Test
  98.  public void getDifferenceBetweenDates() {
  99.      System.out.println("Difference between two dates :: " + Java8DateUtility.getDifferenceBetweenDates(LocalTime.now(), LocalTime.now().plusHours(12)));
  100.  }
  102.  @Test
  103.  public void getLocalDateTimeUsingParseMethod() {
  104.      System.out.println("Get local date time using parse method :: " + Java8DateUtility.getLocalDateTimeUsingParseMethod(DateTimeFormatter.BASIC_ISO_DATE.toString()));
  105.  }
  107.  @Test
  108.  public void convertDateToLocalDate() {
  109.      System.out.println("Convert Date to LocalDate :: " + Java8DateUtility.convertDateToLocalDate(new Date()));
  110.  }
  112.  @Test
  113.  public void convertCalenderToLocalDateTest() {
  114.      System.out.println("Convert Calender to LocalDate :: " + Java8DateUtility.convertDateToLocalDate(Calendar.getInstance().getTime()));
  115.  }
  116. }

运行JUnit测试案例将打印输出。

  1. Next Day ::2018-07-22
  2. Get Day Of Week :: SATURDAY
  3. Get Previous Day :: 2018-07-20
  4. Difference between two dates :: PT-12H
  5. Time after 2 hours : 19:40:51.641
  6. Added hours to time :: 19:40:51.641
  7. 2014 is not a Leap year
  8. local time now : 18:40:51.642
  9. What is value of this instant 2018-07-21T13:10:51.642Z
  10. get time stamp ::2018-07-21T13:10:51.642Z
  11. Convert Date to LocalDate :: 2018-07-21T18:40:51.657
  12. Convert Calender to LocalDate :: 2018-07-21T18:40:51.660
  13. Year : 2018 Month : 7 day : 21   
  14. Today 2018-07-21 and date1 2018-07-21 are same date 
  15. Current date ::2018-07-21
  16. Get start of day :: 2018-07-21T00:00
  17. Current date and time in a particular timezone : 2018-07-21T18:40:51.693-07:00[America/Los_Angeles]
  18. America/Los_Angeles Zone :: 2018-07-21T18:40:51.693-07:00[America/Los_Angeles]
  19. Get First day of Month :: 2018-07-01
  20. 2018-07-21T18:40:51.711+02:00[Europe/Paris]

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