LocalDate、LocalTime、Instant、Duration、Period
1.1使用LocalDate和LocalTime
1.1.1LocalDate的建立方式和相关方法使用示例
@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);
//不能够写成2019-11-1 会报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对象的建立方式以及相关方法示例
@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);//当前时间
// 写13:9:22会报错，DateTimeParseException异常，能够传一个DateTimeFormatter自定义格式
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对象3种建立方式以及相关方法示例
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);
// 转化
LocalDate date2 = dateTime2.toLocalDate();
LocalTime time2 = dateTime2.toLocalTime();
}
1.1.4 机器的日期和时间格式
你能够经过向静态工厂方法ofEpochSecond传递一个表明秒数的值建立一个该类的实例。静态工厂方法ofEpochSecond还有一个加强的重载版本，它接收第二个以纳秒为单位的参数值，对传入做为秒数的参数进行调整。重载的版本会调整纳秒参数，确保保存的纳秒分片在0到999 999999之间。这意味着下面这些对ofEpochSecond工厂方法的调用会返回几乎一样的Instant对象：java
Instant.ofEpochSecond(3); Instant.ofEpochSecond(3, 0); // 2 秒以后再加上100万纳秒（1秒） Instant.ofEpochSecond(2, 1_000_000_000); // 4秒以前的100万纳秒（1秒） Instant.ofEpochSecond(4, -1_000_000_000);
正如你已经在LocalDate及其余为便于阅读而设计的日期-时间类中所看到的那样，Instant类也支持静态工厂方法now，它可以帮你获取当前时刻的时间戳。咱们想要特别强调一点，Instant的设计初衷是为了便于机器使用。它包含的是由秒及纳秒所构成的数字。因此，它没法处理那些咱们很是容易理解的时间单位。好比下面这段语句：安全
int day = Instant.now().get(ChronoField.DAY_OF_MONTH);
它会抛出下面这样的异常：spa
Exception in thread "main" java.time.temporal.UnsupportedTemporalTypeException: Unsupported field: DayOfMonth
你能够经过Duration和Period类使用Instant线程
1.1.5 定义Duration和Period（时间间隔对象）
Duration：能够传2个localTime对象，localDateTime对象或者Instant对象Period：用年，月，日建模，能够传2个localDate对象
Duration d1 = Duration.between(time1, time2); Duration d2 = Duration.between(dateTime1, dateTime2); Duration d3 = Duration.between(instant1, instant2);
由 于LocalDateTime和Instant是为不一样的目的而设计的，一个是为了便于人阅读使用，另外一个是为了便于机器处理，因此你不能将两者混用。若是你试图在这两类对象之间建立duration，会触发一个DateTimeException异常 。 若是你须要以年、月或者日的方式对多个时间单位建模，可使用Period类。使用该类的工厂方法between，你可使用获得两个LocalDate之间的时长，以下所示 :设计
Period period = Period.between(LocalDate.of(2019, 11, 07), LocalDate.of(2019, 11, 07));
Duration和Period类都提供了不少很是方便的工厂类，直接建立对应的实例；换句话说，就像下面这段代码那样，再也不是只能以两个temporal对象的差值的方式来定义它们的对象。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 操纵 解析和格式化日期
1.2.1
-
以比较直观的方式操纵LocalDate的属性
下面的这段代码中全部的方法都返回一个修改了属性的对象。它们都不会修改原来的对象！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
- 以相对方式修改LocalDate的属性
@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类的工厂方法对象
1.2.4自定义格式化输出日期
新版本，咱们拥有一个线程安全的类：DateTimeFormatter 来看代码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);
// 自定义格式
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);
// 带时区的日期(本地化)
DateTimeFormatter italianFormatter = DateTimeFormatter.ofPattern("d. MMMM yyyy", Locale.ITALIAN);
String formattedDate2 = date.format(italianFormatter);
LocalDate date4 = LocalDate.parse(formattedDate2, italianFormatter);
}