Java中LocalDate,LocalDateTime,Date,日期串相互转换_Java

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: