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  • java8新特性 日期

    1. LocalDateTime

    2. Instant

    package com.atguigu.java8;
    
    import java.time.DayOfWeek;
    import java.time.Duration;
    import java.time.Instant;
    import java.time.LocalDate;
    import java.time.LocalDateTime;
    import java.time.OffsetDateTime;
    import java.time.Period;
    import java.time.ZoneId;
    import java.time.ZoneOffset;
    import java.time.ZonedDateTime;
    import java.time.format.DateTimeFormatter;
    import java.time.temporal.TemporalAdjusters;
    import java.util.Set;
    
    import org.junit.Test;
    
    public class TestLocalDateTime {
        
        //6.ZonedDate、ZonedTime、ZonedDateTime : 带时区的时间或日期
        @Test
        public void test7(){
            LocalDateTime ldt = LocalDateTime.now(ZoneId.of("Asia/Shanghai"));
            System.out.println(ldt);
            
            ZonedDateTime zdt = ZonedDateTime.now(ZoneId.of("US/Pacific"));
            System.out.println(zdt);
        }
        
        @Test
        public void test6(){
            Set<String> set = ZoneId.getAvailableZoneIds();
            set.forEach(System.out::println);
        }
    
        
        //5. DateTimeFormatter : 解析和格式化日期或时间
        @Test
        public void test5(){
    //        DateTimeFormatter dtf = DateTimeFormatter.ISO_LOCAL_DATE;
            
            DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy年MM月dd日 HH:mm:ss E");
            
            LocalDateTime ldt = LocalDateTime.now();
            String strDate = ldt.format(dtf);
            
            System.out.println(strDate);
            
            LocalDateTime newLdt = ldt.parse(strDate, dtf);
            System.out.println(newLdt);
        }
        
        //4. TemporalAdjuster : 时间校正器
        @Test
        public void test4(){
        LocalDateTime ldt = LocalDateTime.now();
            System.out.println(ldt);
            
            LocalDateTime ldt2 = ldt.withDayOfMonth(10);
            System.out.println(ldt2);
            
            LocalDateTime ldt3 = ldt.with(TemporalAdjusters.next(DayOfWeek.SUNDAY));
            System.out.println(ldt3);
            
            //自定义:下一个工作日
            LocalDateTime ldt5 = ldt.with((l) -> {
                LocalDateTime ldt4 = (LocalDateTime) l;
                
                DayOfWeek dow = ldt4.getDayOfWeek();
                
                if(dow.equals(DayOfWeek.FRIDAY)){
                    return ldt4.plusDays(3);
                }else if(dow.equals(DayOfWeek.SATURDAY)){
                    return ldt4.plusDays(2);
                }else{
                    return ldt4.plusDays(1);
                }
            });
            
            System.out.println(ldt5);
            
        }
        
        //3.
        //Duration : 用于计算两个“时间”间隔
        //Period : 用于计算两个“日期”间隔
        @Test
        public void test3(){
            Instant ins1 = Instant.now();
            
            System.out.println("--------------------");
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
            }
            
            Instant ins2 = Instant.now();
            
            System.out.println("所耗费时间为:" + Duration.between(ins1, ins2));
            
            System.out.println("----------------------------------");
            
            LocalDate ld1 = LocalDate.now();
            LocalDate ld2 = LocalDate.of(2011, 1, 1);
            
            Period pe = Period.between(ld2, ld1);
            System.out.println(pe.getYears());
            System.out.println(pe.getMonths());
            System.out.println(pe.getDays());
        }
        
        //2. Instant : 时间戳。 (使用 Unix 元年  1970年1月1日 00:00:00 所经历的毫秒值)
        @Test
        public void test2(){
            Instant ins = Instant.now();  //默认使用 UTC 时区
            System.out.println(ins);
            
            OffsetDateTime odt = ins.atOffset(ZoneOffset.ofHours(8));
            System.out.println(odt);
            
            System.out.println(ins.getNano());
            
            Instant ins2 = Instant.ofEpochSecond(5);
            System.out.println(ins2);
        }
        
        //1. LocalDate、LocalTime、LocalDateTime
        @Test
        public void test1(){
            LocalDateTime ldt = LocalDateTime.now();
            System.out.println(ldt);
            
            LocalDateTime ld2 = LocalDateTime.of(2016, 11, 21, 10, 10, 10);
            System.out.println(ld2);
            
            LocalDateTime ldt3 = ld2.plusYears(20);
            System.out.println(ldt3);
            
            LocalDateTime ldt4 = ld2.minusMonths(2);
            System.out.println(ldt4);
            
            System.out.println(ldt.getYear());
            System.out.println(ldt.getMonthValue());
            System.out.println(ldt.getDayOfMonth());
            System.out.println(ldt.getHour());
            System.out.println(ldt.getMinute());
            System.out.println(ldt.getSecond());
        }
    
    }

    以上代码仅供学习参考使用

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  • 原文地址:https://www.cnblogs.com/mengjianzhou/p/9044070.html
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