Java8中LocalDate的使用---项目中日期处理

r囧r小猫 2022-05-26 05:50 270阅读 0赞

// 获取当前日期
            LocalDate now = LocalDate.now();
            // 设置日期
            LocalDate now2 = LocalDate.of(2099, 2, 28);
            // 解析日期，格式必须是yyyy-MM-dd
            LocalDate now3 = LocalDate.parse("2018-01-12");
            DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy/MM/dd");
            String formatRs = now.format(dtf);
            // 取本月第一天
            LocalDate firstDay = now.with(TemporalAdjusters.firstDayOfMonth());
            LocalDate firstDay2 = now.withDayOfMonth(1);
            // 取本月第2天
            LocalDate secondDay = now.withDayOfMonth(2);
            LocalDate nextMonthDay = now.with(TemporalAdjusters.firstDayOfNextMonth());
            LocalDate nextYearDay = now.with(TemporalAdjusters.firstDayOfNextYear());
            // 明年的这一天
            LocalDate localDate = now.plusYears(1);
            // 当前日期加上往后推20天
            LocalDate plusDate = now.plus(20, ChronoUnit.DAYS);
            LocalDate plusYear = now.plus(10, ChronoUnit.YEARS);
            // 当前日期往前推10天
            LocalDate minusDay = now.minusDays(10);
            LocalDate minusYear = now.minus(10, ChronoUnit.YEARS);
            //localDate转Date
            ZoneId zoneId = ZoneId.systemDefault();
            ZonedDateTime zdt = now.atStartOfDay(zoneId);
            Instant instant = zdt.toInstant();
            Date fromDate = Date.from(instant);
            // Date转LocalDate
            Date date = new Date();
            Instant instantToUse = date.toInstant();
            ZoneId zoneIdToUse = ZoneId.systemDefault();
            LocalDate localDateToShow = instantToUse.atZone(zoneIdToUse).toLocalDate();
            // 比较日期大小
            boolean b1 = localDateToShow.equals(LocalDate.of(2018, 04, 27));
            boolean b2= localDateToShow.equals(LocalDate.of(2018, 04, 26));
            // 判断日期前后  -> false
            boolean b3 = localDateToShow.isAfter(LocalDate.of(2018, 04, 26));//false
            boolean b4 = localDateToShow.isAfter(LocalDate.of(2018, 04, 25));//true
            boolean b5 = localDateToShow.isBefore(LocalDate.of(2018, 04, 26));//false
            boolean b6 = localDateToShow.isBefore(LocalDate.of(2018, 04, 25));//false
            boolean b7 = localDateToShow.isBefore(LocalDate.of(2018, 04, 27));//true
            // 计算两个日期之间的时间间隔   格式为：x年x月x天
            Period between = Period.between(localDateToShow, LocalDate.of(2018, 05, 28));
            long bwDays = ChronoUnit.DAYS.between(localDateToShow, LocalDate.of(2018, 05, 28));

目前已知：

1、最新JDBC映射将把数据库的日期类型和Java 8的新类型关联起来：

SQL -> Java
    --------------------------
    date -> LocalDate
    time -> LocalTime
    timestamp -> LocalDateTime

2、框架支持

spring4以支持，mybatis3不支持。