1、LocalDate、LocalTime、LocalDateTime
package demo; import java.time.LocalDate; import java.time.LocalDateTime; import java.time.LocalTime; /** * @description: demo17 * @author: liuyang * @create: 2021-08-30 16:21 */ public class Demo17 { public static void main(String[] args) { // 当前日期 LocalDate localDate = LocalDate.now(); // 当前时间 LocalTime localTime = LocalTime.now(); // 当前日期+时间 LocalDateTime localDateTime = LocalDateTime.now(); System.out.println(localDate); System.out.println(localTime); System.out.println(localDateTime); // 创建指定日期对象 LocalDate localDate1 = LocalDate.of(2019, 8, 30); // 创建指定日期时间对象 LocalDateTime localDateTime1 = LocalDateTime.of(2021, 8, 30, 16, 31, 50); System.out.println(localDate1); System.out.println(localDateTime1); // 一个月的第几天 System.out.println(localDateTime1.getDayOfMonth()); // 一周的第几天 System.out.println(localDateTime1.getDayOfWeek()); // 月份英文 System.out.println(localDateTime1.getMonth()); // 月份数字 System.out.println(localDateTime1.getMonthValue()); // 时间中的分钟 System.out.println(localDateTime1.getMinute()); // 在localDate1的基础上得到一个新的日期对象且为一个月的第18天 LocalDate localDate2 = localDate1.withDayOfMonth(18); // 在localDateTime2的基础上得到一个新的日期时间对象且小时数为18 LocalDateTime localDateTime2 = localDateTime1.withHour(18); System.out.println(localDate2); System.out.println(localDateTime2); // 在localDate3的基础上得到一个新的日期对象且新日期在原来日期上加1天 LocalDate localDate3 = localDate1.plusDays(1); // 在localDateTime3的基础上得到一个新的日期时间对象且在原来的小时上减去4小时 LocalDateTime localDateTime3 = localDateTime1.minusHours(4); System.out.println(localDate3); System.out.println(localDateTime3); } }
2、Instant(瞬时点)
package demo; import java.time.Instant; import java.time.OffsetDateTime; import java.time.ZoneOffset; /** * @description: demo18 * @author: liuyang * @create: 2021-08-30 16:54 */ public class Demo18 { public static void main(String[] args) { // 获取本初子午线对应的标准时间 Instant instant = Instant.now(); // 获取东八区对应的时间 OffsetDateTime offsetDateTime = instant.atOffset(ZoneOffset.ofHours(8)); System.out.println(instant); System.out.println(offsetDateTime); // 获取瞬时点对应的毫秒数 long epochMilli = instant.toEpochMilli(); System.out.println(epochMilli); // 某个毫秒数对应的瞬时点 Instant instant1 = Instant.ofEpochMilli(epochMilli); System.out.println(instant1); } }
3、日期时间的格式化和解析
package demo; import java.time.LocalDate; import java.time.LocalDateTime; import java.time.LocalTime; import java.time.format.DateTimeFormatter; import java.time.format.FormatStyle; /** * @description: demo19 * @author: liuyang * @create: 2021-08-30 17:55 */ public class Demo19 { public static void main(String[] args) { /** * 预定义的标准格式 * DateTimeFormatter.ISO_LOCAL_DATE * DateTimeFormatter.ISO_LOCAL_TIME * DateTimeFormatter.ISO_LOCAL_DATE_TIME */ LocalDateTime localDateTime = LocalDateTime.now(); DateTimeFormatter formatter = DateTimeFormatter.ISO_LOCAL_DATE; String result = formatter.format(localDateTime); System.out.println(result); // 2021-08-30 LocalDate localDate = LocalDate.parse("2021-08-30", formatter); System.out.println(localDate); // 2021-08-30 DateTimeFormatter formatter1 = DateTimeFormatter.ISO_LOCAL_TIME; String result1 = formatter1.format(localDateTime); System.out.println(result1); // 17:59:23.012 LocalTime localTime = LocalTime.parse("17:59:23.012", formatter1); System.out.println(localTime); // 17:59:23.012 DateTimeFormatter formatter2 = DateTimeFormatter.ISO_LOCAL_DATE_TIME; String result2 = formatter2.format(localDateTime); System.out.println(result2); // 2021-08-30T18:00:24.774 LocalDateTime localDateTime1 = LocalDateTime.parse("2021-08-30T18:00:24.774", formatter2); System.out.println(localDateTime1); // 2021-08-30T18:00:24.774 /** * 本地相关的格式 * 适用于LocalDate的格式： * FormatStyle.FULL、FormatStyle.LONG、FormatStyle.MEDIUM、FormatStyle.SHORT * 适用于LocalDateTime的格式： * FormatStyle.LONG、FormatStyle.MEDIUM、FormatStyle.SHORT */ // LocalDate开始 LocalDate localDate1 = LocalDate.now(); DateTimeFormatter formatter3 = DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL); String result3 = formatter3.format(localDate1); System.out.println(result3); // 2021年8月30日 星期一 DateTimeFormatter formatter4 = DateTimeFormatter.ofLocalizedDate(FormatStyle.LONG); String result4 = formatter4.format(localDate1); System.out.println(result4); // 2021年8月30日 DateTimeFormatter formatter5 = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM); String result5 = formatter5.format(localDate1); System.out.println(result5); // 2021-8-30 DateTimeFormatter formatter6 = DateTimeFormatter.ofLocalizedDate(FormatStyle.SHORT); String result6 = formatter6.format(localDate1); System.out.println(result6); // 21-8-30 // LocalDateTime开始 LocalDateTime localDateTime2 = LocalDateTime.now(); DateTimeFormatter formatter7 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.LONG); String result7 = formatter7.format(localDateTime2); System.out.println(result7); // 2021年8月30日 下午06时37分36秒 DateTimeFormatter formatter8 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM); String result8 = formatter8.format(localDateTime2); System.out.println(result8); // 2021-8-30 18:38:20 DateTimeFormatter formatter9 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.SHORT); String result9 = formatter9.format(localDateTime2); System.out.println(result9); // 21-8-30 下午6:39 DateTimeFormatter formatter10 = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"); String result10 = formatter10.format(LocalDateTime.now()); System.out.println(result10); // 2021-08-30 18:50:07 LocalDateTime localDateTime3 = LocalDateTime.parse("2021-08-30 18:49:39", formatter10); System.out.println(localDateTime3); // 2021-08-30T18:49:39 } }