新的日期API LocalDate | LocalTime | LocalDateTime
public class Main {
/**
* 关于LocalDateTime
*/
@Test
public void test1(){
LocalDateTime date=LocalDateTime.now();
System.out.println(date);//输出：2019-03-24T10:20:21.656
System.out.println(date.getYear());
System.out.println(date.getMonthValue());
System.out.println(date.getDayOfMonth());
System.out.println(date.getHour());
System.out.println(date.getMinute());
System.out.println(date.getSecond());
System.out.println(date.getNano());
// 手动创建一个LocalDateTime实例
LocalDateTime date2 = LocalDateTime.of(2017, 12, 17, 9, 31, 31, 31);
System.out.println(date2);
// 进行加操作，得到新的日期实例
LocalDateTime date3 = date2.plusDays(12);
System.out.println(date3);
// 进行减操作，得到新的日期实例
LocalDateTime date4 = date3.minusYears(2);
System.out.println(date4);
}
/**
* 关于时间戳
*/
@Test
public void test2(){
Instant ins=Instant.now();
//默认获取UTC时区
System.out.println(ins);
System.out.println(LocalDateTime.now().toInstant(ZoneOffset.of("+8")).toEpochMilli());
System.out.println(System.currentTimeMillis());
System.out.println(Instant.now().toEpochMilli());
System.out.println(Instant.now().atOffset(ZoneOffset.ofHours(8)).toInstant().toEpochMilli());
}
/**
*
*/
@Test
public void test3(){
// Duration:计算两个时间之间的间隔
// Period：计算两个日期之间的间隔
Instant ins1 = Instant.now();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Instant ins2 = Instant.now();
Duration dura = Duration.between(ins1, ins2);
System.out.println(dura.getSeconds());
System.out.println(dura.toMillis());
System.out.println("======================");
LocalTime localTime = LocalTime.now();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
LocalTime localTime2 = LocalTime.now();
Duration du2 = Duration.between(localTime, localTime2);
System.out.println(du2);
System.out.println(du2.toMillis());
}
@Test
public void test4(){
LocalDate localDate =LocalDate.now();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
LocalDate localDate2 = LocalDate.of(2019,3,25);
Period pe = Period.between(localDate, localDate2);
System.out.println(pe.getDays());
}
@Test
public void test5(){
// temperalAdjust 时间校验器
// 例如获取下周日 下一个工作日
LocalDateTime ldt1 = LocalDateTime.now();
System.out.println(ldt1);
// 获取一年中的第一天
LocalDateTime ldt2 = ldt1.withDayOfYear(1);
System.out.println(ldt2);
// 获取一个月中的第一天
LocalDateTime ldt3 = ldt1.withDayOfMonth(1);
System.out.println(ldt3);
LocalDateTime ldt4 = ldt1.with(TemporalAdjusters.next(DayOfWeek.FRIDAY));
System.out.println(ldt4);
// 获取下一个工作日
LocalDateTime ldt5 = ldt1.with((t) -> {
LocalDateTime ldt6 = (LocalDateTime)t;
DayOfWeek dayOfWeek = ldt6.getDayOfWeek();
if (DayOfWeek.FRIDAY.equals(dayOfWeek)){
return ldt6.plusDays(3);
}
else if (DayOfWeek.SATURDAY.equals(dayOfWeek)){
return ldt6.plusDays(2);
}
else {
return ldt6.plusDays(1);
}
});
System.out.println(ldt5);
}
@Test
public void test6(){
// DateTimeFormatter: 格式化时间/日期
// 自定义格式
LocalDateTime ldt = LocalDateTime.now();
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy年MM月dd日");
String strDate1 = ldt.format(formatter);
String strDate = formatter.format(ldt);
System.out.println(strDate);
System.out.println(strDate1);
// 使用api提供的格式
DateTimeFormatter dtf = DateTimeFormatter.ISO_DATE;
LocalDateTime ldt2 = LocalDateTime.now();
String strDate3 = dtf.format(ldt2);
System.out.println(strDate3);
// 解析字符串to时间
DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
LocalDateTime time = LocalDateTime.now();
String localTime = df.format(time);
LocalDateTime ldt4 = LocalDateTime.parse("2017-09-28 17:07:05",df);
System.out.println("LocalDateTime转成String类型的时间："+localTime);
System.out.println("String类型的时间转成LocalDateTime："+ldt4);
}
@Test
public void test7(){
LocalDateTime now = LocalDateTime.now(ZoneId.of("Asia/Shanghai"));
System.out.println(now);
LocalDateTime now2 = LocalDateTime.now();
ZonedDateTime zdt = now2.atZone(ZoneId.of("Asia/Shanghai"));
System.out.println(zdt);
Set<String> set = ZoneId.getAvailableZoneIds();
set.stream().forEach(System.out::println);
}
}
1、LocalDate
@Test
public void test1(){
//获取当前日期,只含年月日 固定格式 yyyy-MM-dd 2018-05-04
LocalDate today = LocalDate.now();
// 根据年月日取日期，5月就是5，
LocalDate oldDate = LocalDate.of(2018, 5, 1);
// 根据字符串取：默认格式yyyy-MM-dd，02不能写成2
LocalDate yesteday = LocalDate.parse("2018-05-03");
// 如果不是闰年 传入29号也会报错
LocalDate.parse("2018-02-29");
}
@Test
public void test2(){
//2018-05-04
LocalDate today = LocalDate.now();
// 取本月第1天： 2018-05-01
LocalDate firstDayOfThisMonth = today.with(TemporalAdjusters.firstDayOfMonth());
// 取本月第2天：2018-05-02
LocalDate secondDayOfThisMonth = today.withDayOfMonth(2);
// 取本月最后一天，再也不用计算是28，29，30还是31： 2018-05-31
LocalDate lastDayOfThisMonth = today.with(TemporalAdjusters.lastDayOfMonth());
// 取下一天：2018-06-01
LocalDate firstDayOf2015 = lastDayOfThisMonth.plusDays(1);
// 取2018年10月第一个周三 so easy?： 2018-10-03
LocalDate thirdMondayOf2018 = LocalDate.parse("2018-10-01").with(TemporalAdjusters.firstInMonth(DayOfWeek.WEDNESDAY));
}
2、LocalDateTime
@Test
public void test1(){
//转化为时间戳 毫秒值
long time1 = LocalDateTime.now().toInstant(ZoneOffset.of("+8")).toEpochMilli();
long time2 = System.currentTimeMillis();
//时间戳转化为localdatetime
DateTimeFormatter df= DateTimeFormatter.ofPattern("YYYY-MM-dd HH:mm:ss.SSS");
System.out.println(df.format(LocalDateTime.ofInstant(Instant.ofEpochMilli(time1), ZoneId.of("Asia/Shanghai"))));
}
3、LocalTime
@Test
public void test1(){
//16:25:46.448(纳秒值)
LocalTime todayTimeWithMillisTime = LocalTime.now();
//16:28:48 不带纳秒值
LocalTime todayTimeWithNoMillisTime = LocalTime.now().withNano(0);
LocalTime time1 = LocalTime.parse("23:59:59");
}
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