LocalDate,LocalDateTime,Date,日期串相互转换

LocalDate,LocalDateTime,Date,日期串相互转换

1. 获取当前时间 XXX.now()

public void testCurrentDate() {
  LocalDate curLocalDate = LocalDate.now();
  System.out.println("地心侠士: "+curLocalDate.toString());
  LocalTime curLoacalTime = LocalTime.now();
  System.out.println("地心侠士: "+curLoacalTime.toString());
  LocalDateTime curLocalDateTime = LocalDateTime.now();
  System.out.println("地心侠士: "+curLocalDateTime.toString());
  Instant curInstant = Instant.now();
  System.out.println("地心侠士: "+ curInstant.toString());
}

输出结果

地心侠士: 2026-02-04
地心侠士: 17:15:59.715639800
地心侠士: 2026-02-04T17:15:59.715639800
地心侠士: 2026-02-04T09:15:59.715639800Z

说明:

• LocalDate,LocalTime,LocalDateTime都是当前时区对应日期或时间
• Instant获取到的是UTC+0 日期和时间
• Z 代表零时区（UTC+0） T 日期和时间的分割符

2. 时间戳转成LocalDateTime

public void testTimestamp() {
  Long timeStamp = 1769577638767L;
  Instant instant = Instant.ofEpochMilli(timeStamp);
  System.out.println("地心侠士: " + instant.toString());
  LocalDateTime cvLocalDate = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
  System.out.println("地心侠士: " + cvLocalDate.toString());
  LocalDateTime localDateT1 = LocalDateTime.ofEpochSecond(timeStamp / 1000, 0, ZoneOffset.ofHours(8));
  System.out.println("地心侠士: " + localDateT1.toString());
}

输出结果

地心侠士: 2026-01-28T05:20:38.767Z
地心侠士: 2026-01-28T13:20:38.767
地心侠士: 2026-01-28T13:20:38

说明:

• 使用方法 LocalDateTime.ofInstant 或者 LocalDateTime.ofEpochSecond
• 使用 ofInstant ,毫秒时间戳可以直接使用
• 使用 ofEpochSecond ,毫秒时间戳需要除以1000
• ofInstant 使用 ZoneId.systemDefault() 获取当时区
• OfEpochSecond 使用 ZoneOffset.ofHours(8) 指定需要的时区
• ZoneId.systemDefault() 当前时区,等同的有 ZoneId.of("Asia/Shanghai") ZoneId.of("GMT+8") ZoneId.of("UTC+08:00") ZoneId.of("+08:00")

3. 时间串转换成LocalDateTime

public void testDateStr() {
  DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS");
  String dateStr = "2026-01-28 18:20:38.767";
  LocalDateTime localDateTime = LocalDateTime.parse(dateStr, df);
  System.out.println("地心侠士: " + localDateTime.toString());
  LocalDateTime defaultParse = LocalDateTime.parse("2026-01-28T18:20:38");
  System.out.println("地心侠士: " + defaultParse.toString());
  DateTimeFormatterBuilder dfBuild = new DateTimeFormatterBuilder();
  DateTimeFormatter dynmicDf = dfBuild.appendPattern("yyyy-MM-dd")
  		.optionalStart()
  		.appendLiteral(' ')
  		.optionalEnd()
  		.optionalStart()
  		.appendLiteral('T')
  		.optionalEnd()
  		.appendPattern("HH:mm:ss")
  		.toFormatter();
  LocalDateTime dynamic1 = LocalDateTime.parse("2026-01-28T18:20:38", dynmicDf);
  System.out.println("地心侠士: " + dynamic1.toString());
  LocalDateTime dynamc2 = LocalDateTime.parse("2026-01-28 18:20:38", dynmicDf);
  System.out.println("地心侠士: " + dynamc2.toString());
}

输出结果:

地心侠士: 2026-01-28T18:20:38.767
地心侠士: 2026-01-28T18:20:38
地心侠士: 2026-01-28T18:20:38
地心侠士: 2026-01-28T18:20:38

说明:

• 使用方法LocalDateTime.parse结合DateTimeFormatter转换
• 默认转换格式为yyyy-MM-ddTHH:mm:ss
• 使用 DateTimeFormatterBuilder 可以实现多种日期串转换成LocalDateTime

4. LocalDateTime转换成成LocalDate和Date

public void testDateConvert() {
  LocalDateTime dt = LocalDateTime.now();
  System.out.println("地心侠士 " + dt.toString());
  System.out.println("LocalDateTime=>LocalDate");
  LocalDate localDate = dt.toLocalDate();
  System.out.println("地心侠士 " + localDate.toString());
  System.out.println("LocalDateTime=>Date");
  Instant instant = dt.toInstant(ZoneOffset.ofHours(8));
  Date d = Date.from(instant);
  System.out.println("地心侠士 " + d);
}

输出结果:

地心侠士 2026-02-06T19:09:35.092605300
LocalDateTime=>LocalDate
地心侠士 2026-02-06
LocalDateTime=>Date
地心侠士 Fri Feb 06 19:09:35 CST 2026

5. Date 转换成LocalDateTime

public void testDateConvert2() {
  Date date = new Date();
  System.out.println("地心侠士 " + date.toString());
  System.out.println("Date=>LocalDateTime");
  Instant instant = date.toInstant();
  LocalDateTime lcd = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
  System.out.println("地心侠士 " + lcd.toString());
}

输出结果:

地心侠士 Fri Feb 06 19:15:38 CST 2026
Date=>LocalDateTime
地心侠士 2026-02-06T19:15:38.122

6. 北京时间时区表示

public void testZone() {
  ZoneId zonidGMT8 = ZoneId.of("GMT+8");
  LocalDateTime gmt8 = LocalDateTime.ofInstant(Instant.now(), zonidGMT8);
  System.out.println("地心侠士: " + gmt8.toString());
  ZoneId zonidAS = ZoneId.of("Asia/Shanghai");
  LocalDateTime as = LocalDateTime.ofInstant(Instant.now(), zonidAS);
  System.out.println("地心侠士: " + as.toString());
  ZoneId zonidUTC8 = ZoneId.of("UTC+08:00");
  LocalDateTime utc = LocalDateTime.ofInstant(Instant.now(), zonidUTC8);
  System.out.println("地心侠士: " + utc.toString());
  ZoneId zonid8 = ZoneId.of("+08:00");
  LocalDateTime ad8= LocalDateTime.ofInstant(Instant.now(), zonid8);
  System.out.println("地心侠士: " + ad8.toString());
}

输出结果:

地心侠士: 2026-02-06T18:35:26.921795200
地心侠士: 2026-02-06T18:35:26.928776600
地心侠士: 2026-02-06T18:35:26.928776600
地心侠士: 2026-02-06T18:35:26.928776600

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