JAVA8新特性随笔

Instant：瞬时实例

LocalDate：本地日期，不包含具体时间。例如：2014-01-14可以用来记录生日、纪念日、加盟日等。

LocalTime：本地时间，不包含日期

LocalDateTime：组合了日期和时间，但不包含时差和时区信息

ZonedDateTime：最完整的日期时间，包含时区和相对UTC或格林威治的时差

日期类和时间类

获取当前时间：LocalDateTime.now();
日期格式化:：LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd hh:mm:ss a"));
获取时间戳：Instant.now()

（Date.from(Instant)将Instant转换成java.util.Date，Date.toInstant()则是将Date类转换成Instant类。）
LocalDateTime转String: LocalDateTime.parse(str,dateTimeFormatter); String转LocalDateTime: localDateTime.format(dateTimeFormatter);
Date转LocalDateTime：LocalDateTime localDateTime = LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault());
LocalDateTime转Date：Date date = Date.from(LocalDateTime.now().atZone(ZoneId.systemDefault()).toInstant());
前端传过来的日期字符串怎么转换并放到数据库

		LocalDate localDate = LocalDate.now();

        System.out.println("LocalDate.now():"+localDate);

        System.out.println("localDate.getYear():"+localDate.getYear());

        System.out.println("localDate.getMonth():"+localDate.getMonth());

        System.out.println("localDate.getMonthValue():"+localDate.getMonthValue());

        System.out.println("localDate.getDayOfMonth():"+localDate.getDayOfMonth());

        System.out.println("localDate.getDayOfWeek():"+localDate.getDayOfWeek());

        System.out.println("localDate.getDayOfWeek().getValue():"+localDate.getDayOfWeek().getValue());

        LocalTime localTime = LocalTime.now();

        System.out.println("当前时间LocalTime.now(): " + localTime);

        System.out.println("当前时间+1小时 localTime.plusHours(1): " + localTime.plusHours(1));

        Clock clock = Clock.systemUTC();

        Clock clock2 = Clock.systemDefaultZone();

        System.out.println("Clock : " + clock.millis());

        System.out.println("clock2 : " + clock2.millis());

        System.out.println("=== 获取当前的时间戳 ===============================================");

        Instant timestamp = Instant.now();

        System.out.println("获取当前的时间戳: "+timestamp);

        System.out.println("=== 格式化日期 ===============================================");

        DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-dd hh:mm:ss a");

        LocalDateTime localDateTime = LocalDateTime.now();

        System.out.println(" LocalDateTime.now(): "+localDateTime);

        System.out.println(" 格式化后的日期："+localDateTime.format(format));

        System.out.println("=== 检查生日等周期性事件 ===============================================");

        LocalDate dateOfBirth = LocalDate.of(2019, 7, 25);

        MonthDay birthday = MonthDay.of(dateOfBirth.getMonth(), dateOfBirth.getDayOfMonth());

        MonthDay currentMonthDay = MonthDay.from(localDate);

        if(currentMonthDay.equals(birthday)){

            System.out.println(" Many Many happy returns of the day !!");

        }else{

            System.out.println(" Sorry, today is not your birthday");

        }

巴特西

JAVA8新特性随笔

日期类和时间类

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