Java8中时间API

instant.atOffset(ZoneOffset.ofHours(8));

import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
public class TestDatetimeFormatter {
    @Test
    public void test1(){
        // 方式一：预定义的标准格式。如：ISO_LOCAL_DATE_TIME;ISO_LOCAL_DATE;ISO_LOCAL_TIME
        DateTimeFormatter formatter = DateTimeFormatter.ISO_LOCAL_DATE_TIME;
        // 格式化:日期-->字符串
        LocalDateTime localDateTime = LocalDateTime.now();
        String str1 = formatter.format(localDateTime);
        System.out.println(localDateTime);
        System.out.println(str1);//2022-12-04T21:02:14.808
        // 解析：字符串 -->日期
        TemporalAccessor parse = formatter.parse("2022-12-04T21:02:14.808");
        LocalDateTime dateTime = LocalDateTime.from(parse);
        System.out.println(dateTime);
    }
    @Test
    public void test2(){
        LocalDateTime localDateTime = LocalDateTime.now();
        // 方式二：
        // 本地化相关的格式。如：ofLocalizedDateTime()
        // FormatStyle.LONG / FormatStyle.MEDIUM / FormatStyle.SHORT :适用于LocalDateTime
        DateTimeFormatter formatter1 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.LONG);
        // 格式化
        String str2 = formatter1.format(localDateTime);
        System.out.println(str2);// 2022年12月4日 下午09时03分55秒
        // 本地化相关的格式。如：ofLocalizedDate()
        // FormatStyle.FULL / FormatStyle.LONG / FormatStyle.MEDIUM / FormatStyle.SHORT : 适用于LocalDate
        DateTimeFormatter formatter2 = DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL);
        // 格式化
        String str3 = formatter2.format(LocalDate.now());
        System.out.println(str3);// 2022年12月4日 星期日
    }
    @Test
    public void test3(){
        //方式三：自定义的方式
        DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy/MM/dd HH:mm:ss");
        //格式化
        String strDateTime = dateTimeFormatter.format(LocalDateTime.now());
        System.out.println(strDateTime); //2022/12/04 21:05:42
        //解析
        TemporalAccessor accessor = dateTimeFormatter.parse("2022/12/04 21:05:42");
        LocalDateTime localDateTime = LocalDateTime.from(accessor);
        System.out.println(localDateTime); //2022-12-04T21:05:42
    }
}

@Test
public void test01() {
    //需要知道一些时区的id
    //Set<String>是一个集合，容器
    Set<String> availableZoneIds = ZoneId.getAvailableZoneIds();
    //快捷模板iter
    for (String availableZoneId : availableZoneIds) {
        System.out.println(availableZoneId);
    }
}
@Test
public void test02(){
    ZonedDateTime t1 = ZonedDateTime.now();
    System.out.println(t1);
    ZonedDateTime t2 = ZonedDateTime.now(ZoneId.of("America/New_York"));
    System.out.println(t2);
}

public class TestPeriodDuration {
    @Test
    public void test01(){
        LocalDate t1 = LocalDate.now();
        LocalDate t2 = LocalDate.of(2018, 12, 31);
        Period between = Period.between(t1, t2);
        System.out.println(between);
        System.out.println("相差的年数："+between.getYears());
        System.out.println("相差的月数："+between.getMonths());
        System.out.println("相差的天数："+between.getDays());
        System.out.println("相差的总数："+between.toTotalMonths());
    }
    @Test
    public void test02(){
        LocalDateTime t1 = LocalDateTime.now();
        LocalDateTime t2 = LocalDateTime.of(2017, 8, 29, 0, 0, 0, 0);
        Duration between = Duration.between(t1, t2);
        System.out.println(between);
        System.out.println("相差的总天数："+between.toDays());
        System.out.println("相差的总小时数："+between.toHours());
        System.out.println("相差的总分钟数："+between.toMinutes());
        System.out.println("相差的总秒数："+between.getSeconds());
        System.out.println("相差的总毫秒数："+between.toMillis());
        System.out.println("相差的总纳秒数："+between.toNanos());
        System.out.println("不够一秒的纳秒数："+between.getNano());
    }
    @Test
    public void test03(){
        //Duration:用于计算两个“时间”间隔，以秒和纳秒为基准
    LocalTime localTime = LocalTime.now();
    LocalTime localTime1 = LocalTime.of(15, 23, 32);
    //between():静态方法，返回Duration对象，表示两个时间的间隔
    Duration duration = Duration.between(localTime1, localTime);
    System.out.println(duration);
    System.out.println(duration.getSeconds());
    System.out.println(duration.getNano());
    LocalDateTime localDateTime = LocalDateTime.of(2016, 6, 12, 15, 23, 32);
    LocalDateTime localDateTime1 = LocalDateTime.of(2017, 6, 12, 15, 23, 32);
    Duration duration1 = Duration.between(localDateTime1, localDateTime);
    System.out.println(duration1.toDays());
    }
    @Test
    public void test4(){
        //Period:用于计算两个“日期”间隔，以年、月、日衡量
    LocalDate localDate = LocalDate.now();
    LocalDate localDate1 = LocalDate.of(2028, 3, 18);
    Period period = Period.between(localDate, localDate1);
    System.out.println(period);
    System.out.println(period.getYears());
    System.out.println(period.getMonths());
    System.out.println(period.getDays());
    Period period1 = period.withYears(2);
    System.out.println(period1);
    }
}

@Test
public void test1(){
    // TemporalAdjuster:时间校正器
  // 获取当前日期的下一个周日是哪天？
  TemporalAdjuster temporalAdjuster = TemporalAdjusters.next(DayOfWeek.SUNDAY);
  LocalDateTime localDateTime = LocalDateTime.now().with(temporalAdjuster);
  System.out.println(localDateTime);
  // 获取下一个工作日是哪天？
  LocalDate localDate = LocalDate.now().with(new TemporalAdjuster() {
      @Override
      public Temporal adjustInto(Temporal temporal) {
          LocalDate date = (LocalDate) temporal;
          if (date.getDayOfWeek().equals(DayOfWeek.FRIDAY)) {
              return date.plusDays(3);
          } else if (date.getDayOfWeek().equals(DayOfWeek.SATURDAY)) {
              return date.plusDays(2);
          } else {
              return date.plusDays(1);
          }
      }
  });
  System.out.println("下一个工作日是：" + localDate);
}