LocalDate、LocalTime、Instant、Duration、Period
1.1使用LocalDate和LocalTime
1.1.1LocalDate的建立方式和相關方法使用示例
@Test
public void localDate() {
LocalDate date = LocalDate.of(2019, 11, 1);
int year = date.getYear();// 2019
Month month = date.getMonth();// NOVEMBER
int day = date.getDayOfMonth();// 1
DayOfWeek dow = date.getDayOfWeek();// FRIDAY
int len = date.lengthOfMonth();// 30
boolean leap = date.isLeapYear();// false
System.out.println(year + ", " + month + ", " + day + ", " + dow + ", " + len + ", " + leap);
LocalDate date2 = LocalDate.now();
int year2 = date2.get(ChronoField.YEAR);//2019
int month2 = date2.get(ChronoField.MONTH_OF_YEAR);// 12
int day2 = date2.get(ChronoField.DAY_OF_MONTH);// 14
int dow2 = date2.get(ChronoField.DAY_OF_WEEK);// 6
System.out.println(year2 + ", " + month2 + ", " + day2 + ", " + dow2);
//不能夠寫成2019-11-1 會報DateTimeParseException
LocalDate date3 = LocalDate.parse("2019-11-01");
int year3 = date3.get(ChronoField.YEAR);//2019
int month3 = date3.get(ChronoField.MONTH_OF_YEAR);// 11
int day3 = date3.get(ChronoField.DAY_OF_MONTH);// 1
int dow3 = date3.get(ChronoField.DAY_OF_WEEK);// 5
System.out.println(year3 + ", " + month3 + ", " + day3 + ", " + dow3);
}
1.1.1LocalTime對象的建立方式以及相關方法示例
@Test
public void localTime() {
LocalTime time = LocalTime.of(11, 06, 23);
int hour = time.getHour();
int minute = time.getMinute();
int second = time.getSecond();
System.out.println(hour + ":" + minute + ":" + second);// 11:6:23
LocalTime time2 = LocalTime.now();
int hour2 = time2.get(ChronoField.HOUR_OF_DAY);
int minute2 = time2.get(ChronoField.MINUTE_OF_HOUR);
int second2 = time2.get(ChronoField.SECOND_OF_MINUTE);
System.out.println(hour2 + ":" + minute2 + ":" + second2);//當前時間
// 寫13:9:22會報錯，DateTimeParseException異常，能夠傳一個DateTimeFormatter自定義格式
LocalTime time3 = LocalTime.parse("13:09:22");
int hour3 = time3.get(ChronoField.HOUR_OF_DAY);
int minute3 = time3.get(ChronoField.MINUTE_OF_HOUR);
int second3 = time3.get(ChronoField.SECOND_OF_MINUTE);
System.out.println(hour3 + ":" + minute3 + ":" + second3);// 13:9:22
}
1.1.3LocalDateTime對象3種建立方式以及相關方法示例
Test
public void localDateTime() {
LocalDate date = LocalDate.now();
LocalTime time = LocalTime.now();
// 建立LocalDateTime
LocalDateTime dateTime = LocalDateTime.of(2019, 11, 1, 13, 32, 28);
LocalDateTime dateTime2 = LocalDateTime.of(date, time);
LocalDateTime dateTime3 = date.atTime(13, 32, 28);
LocalDateTime dateTime4 = date.atTime(time);
LocalDateTime dateTime6 = time.atDate(date);
// 轉化
LocalDate date2 = dateTime2.toLocalDate();
LocalTime time2 = dateTime2.toLocalTime();
}
1.1.4 機器的日期和時間格式
你能夠經過向靜態工廠方法ofEpochSecond傳遞一個表明秒數的值建立一個該類的實例。靜態工廠方法ofEpochSecond還有一個加強的重載版本，它接收第二個以納秒爲單位的參數值，對傳入做爲秒數的參數進行調整。重載的版本會調整納秒參數，確保保存的納秒分片在0到999 999999之間。這意味着下面這些對ofEpochSecond工廠方法的調用會返回幾乎一樣的Instant對象：java
Instant.ofEpochSecond(3); Instant.ofEpochSecond(3, 0); // 2 秒以後再加上100萬納秒（1秒） Instant.ofEpochSecond(2, 1_000_000_000); // 4秒以前的100萬納秒（1秒） Instant.ofEpochSecond(4, -1_000_000_000);
正如你已經在LocalDate及其餘爲便於閱讀而設計的日期-時間類中所看到的那樣，Instant類也支持靜態工廠方法now，它可以幫你獲取當前時刻的時間戳。咱們想要特別強調一點，Instant的設計初衷是爲了便於機器使用。它包含的是由秒及納秒所構成的數字。因此，它沒法處理那些咱們很是容易理解的時間單位。好比下面這段語句：安全
int day = Instant.now().get(ChronoField.DAY_OF_MONTH);
它會拋出下面這樣的異常：spa
Exception in thread "main" java.time.temporal.UnsupportedTemporalTypeException: Unsupported field: DayOfMonth
你能夠經過Duration和Period類使用Instant線程
1.1.5 定義Duration和Period（時間間隔對象）
Duration：能夠傳2個localTime對象，localDateTime對象或者Instant對象Period：用年，月，日建模，能夠傳2個localDate對象
Duration d1 = Duration.between(time1, time2); Duration d2 = Duration.between(dateTime1, dateTime2); Duration d3 = Duration.between(instant1, instant2);
由 於LocalDateTime和Instant是爲不一樣的目的而設計的，一個是爲了便於人閱讀使用，另外一個是爲了便於機器處理，因此你不能將兩者混用。若是你試圖在這兩類對象之間建立duration，會觸發一個DateTimeException異常 。 若是你須要以年、月或者日的方式對多個時間單位建模，可使用Period類。使用該類的工廠方法between，你可使用獲得兩個LocalDate之間的時長，以下所示 :設計
Period period = Period.between(LocalDate.of(2019, 11, 07), LocalDate.of(2019, 11, 07));
Duration和Period類都提供了不少很是方便的工廠類，直接建立對應的實例；換句話說，就像下面這段代碼那樣，再也不是隻能以兩個temporal對象的差值的方式來定義它們的對象。code
Duration threeMinutes = Duration.ofMinutes(3); Duration fourMinutes = Duration.of(4, ChronoUnit.MINUTES); Period tenDay = Period.ofDays(10); Period threeWeeks = Period.ofWeeks(3); Period twoYearsSixMonthsOneDay = Period.of(2, 6, 1);
1.2 操縱 解析和格式化日期
1.2.1
-
以比較直觀的方式操縱LocalDate的屬性
下面的這段代碼中全部的方法都返回一個修改了屬性的對象。它們都不會修改原來的對象！orm
LocalDate date1 = LocalDate.of(2019, 11, 1);//2019-11-01 LocalDate date2 = date1.withYear(2020);//2020-11-01 LocalDate date3 = date2.withDayOfMonth(25);//2020-11-25 LocalDate date4 = date3.with(ChronoField.MONTH_OF_YEAR, 9);//2020-09-25
- 以相對方式修改LocalDate的屬性
@Test
public void editDateTime() {
LocalDate date1 = LocalDate.of(2019, 11, 01);// 2019-11-01
LocalDate date2 = date1.plusWeeks(1);// 2019-11-08
LocalDate date3 = date2.minusYears(2);// 2017-11-08
LocalDate date4 = date3.plus(6, ChronoUnit.MONTHS);// 2018-05-08
}
1.2.3 TemporalAdjuster
@Test
public void adjust() {
LocalDate date1 = LocalDate.of(2019, 11, 01);// 2019-11-01
LocalDate date2 = date1.with(TemporalAdjusters.nextOrSame(DayOfWeek.SUNDAY));// 2019-11-03
LocalDate date3 = date2.with(TemporalAdjusters.lastDayOfMonth());// 2019-11-30
}
TemporalAdjuster類的工廠方法對象
1.2.4自定義格式化輸出日期
新版本，咱們擁有一個線程安全的類：DateTimeFormatter 來看代碼blog
@Test
public void formatPrint() {
LocalDate date = LocalDate.of(2019, 11, 01);
String s1 = date.format(DateTimeFormatter.BASIC_ISO_DATE);// 20191101
String s2 = date.format(DateTimeFormatter.ISO_LOCAL_DATE);// 2019-11-01
LocalDate date1 = LocalDate.parse("20191101", DateTimeFormatter.BASIC_ISO_DATE);
LocalDate date2 = LocalDate.parse("2019-11-01", DateTimeFormatter.ISO_LOCAL_DATE);
// 自定義格式
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy");
String formattedDate = date.format(formatter);
System.out.println(formattedDate);// 01/11/2019
LocalDate date3 = LocalDate.parse(formattedDate, formatter);
// 帶時區的日期(本地化)
DateTimeFormatter italianFormatter = DateTimeFormatter.ofPattern("d. MMMM yyyy", Locale.ITALIAN);
String formattedDate2 = date.format(italianFormatter);
LocalDate date4 = LocalDate.parse(formattedDate2, italianFormatter);
}