我正在尝试将ISO 8601格式的字符串转换为java.util.Date。

我发现模式yyyy-MM-dd'T'HH:mm:ssZ是符合iso8601的,如果使用区域设置(比较样本)。

然而,使用java.text。SimpleDateFormat,我无法转换正确格式化的字符串2010-01-01T12:00:00+01:00。我必须首先将其转换为2010-01-01T12:00:00+0100,不带冒号。

目前的解决方案是

SimpleDateFormat ISO8601DATEFORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.GERMANY);
String date = "2010-01-01T12:00:00+01:00".replaceAll("\\+0([0-9]){1}\\:00", "+0$100");
System.out.println(ISO8601DATEFORMAT.parse(date));

这显然不太好。是我错过了什么,还是有更好的解决方案?


回答

感谢JuanZe的评论,我发现了Joda-Time魔法,这里也有描述。

所以解是

DateTimeFormatter parser2 = ISODateTimeFormat.dateTimeNoMillis();
String jtdate = "2010-01-01T12:00:00+01:00";
System.out.println(parser2.parseDateTime(jtdate));

或者更简单地说,通过构造函数使用默认解析器:

DateTime dt = new DateTime( "2010-01-01T12:00:00+01:00" ) ;

对我来说,这很好。


当前回答

我很惊讶,甚至没有一个java库支持所有ISO 8601日期格式https://en.wikipedia.org/wiki/ISO_8601。Joda DateTime支持其中大部分,但不是全部,因此我添加了自定义逻辑来处理所有这些。这是我的实现。

import java.text.ParseException; import java.util.Date; import org.apache.commons.lang3.time.DateUtils; import org.joda.time.DateTime; public class ISO8601DateUtils { /** * It parses all the date time formats from https://en.wikipedia.org/wiki/ISO_8601 and returns Joda DateTime. * Zoda DateTime does not support dates of format 20190531T160233Z, and hence added custom logic to handle this using SimpleDateFormat. * @param dateTimeString ISO 8601 date time string * @return */ public static DateTime parse(String dateTimeString) { try { return new DateTime( dateTimeString ); } catch(Exception e) { try { Date dateTime = DateUtils.parseDate(dateTimeString, JODA_NOT_SUPPORTED_ISO_DATES); return new DateTime(dateTime.getTime()); } catch (ParseException e1) { throw new RuntimeException(String.format("Date %s could not be parsed to ISO date", dateTimeString)); } } } private static String[] JODA_NOT_SUPPORTED_ISO_DATES = new String[] { // upto millis "yyyyMMdd'T'HHmmssSSS'Z'", "yyyyMMdd'T'HHmmssSSSZ", "yyyyMMdd'T'HHmmssSSSXXX", "yyyy-MM-dd'T'HHmmssSSS'Z'", "yyyy-MM-dd'T'HHmmssSSSZ", "yyyy-MM-dd'T'HHmmssSSSXXX", // upto seconds "yyyyMMdd'T'HHmmss'Z'", "yyyyMMdd'T'HHmmssZ", "yyyyMMdd'T'HHmmssXXX", "yyyy-MM-dd'T'HHmmss'Z'", "yyyy-MM-dd'T'HHmmssZ", "yyyy-MM-dd'T'HHmmssXXX", // upto minutes "yyyyMMdd'T'HHmm'Z'", "yyyyMMdd'T'HHmmZ", "yyyyMMdd'T'HHmmXXX", "yyyy-MM-dd'T'HHmm'Z'", "yyyy-MM-dd'T'HHmmZ", "yyyy-MM-dd'T'HHmmXXX", //upto hours is already supported by Joda DateTime }; }

其他回答

博士tl;

OffsetDateTime.parse ( "2010-01-01T12:00:00+01:00" )

或者对于Java 12+,使用Instant。解析见Arvind Kumar Avinash的答案。

使用java.time

新的java。Java 8中的time包,后来受到Joda-Time的启发。

OffsetDateTime类表示时间轴上的一个时刻,该时刻具有与utc的偏移量,而不是时区。

OffsetDateTime odt = OffsetDateTime.parse ( "2010-01-01T12:00:00+01:00" );

调用toString生成标准ISO 8601格式的字符串:

2010 - 01 - 01 - t12:00 + 01:00

要通过UTC的镜头看到相同的值,提取一个Instant或将偏移量从+01:00调整为00:00。

Instant instant = odt.toInstant();  

…or…

OffsetDateTime odtUtc = odt.withOffsetSameInstant( ZoneOffset.UTC );

根据需要调整时区。时区是一个区域的utc偏移值的历史记录,并带有一组处理异常(如夏令时)的规则。因此,尽可能应用时区,而不仅仅是偏移量。

ZonedDateTime zonedDateTimeMontréal = odt.atZoneSameInstant( ZoneId.of( "America/Montreal" ) );

对于只有日期的值,使用LocalDate。

LocalDate ld = LocalDate.of( 2010 , Month.JANUARY , 1 ) ;

Or:

LocalDate ld = LocalDate.parse( "2010-01-01" ) ;

关于java.time

java。时间框架内置于Java 8及更高版本中。这些类取代了麻烦的旧遗留日期-时间类,如java.util。日期,日历和简单日期格式。

要了解更多,请参阅Oracle教程。搜索Stack Overflow可以找到很多例子和解释。规范是JSR 310。

Joda-Time项目现在处于维护模式,建议迁移到java。时间类。

你可以交换java。Time对象直接使用数据库。使用符合JDBC 4.2或更高版本的JDBC驱动程序。不需要字符串,不需要java。sql。*类。Hibernate 5和JPA 2.2支持java.time。

从哪里获取java。时间类?

Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation. Java 9 brought some minor features and fixes. Java SE 6 and Java SE 7 Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport. Android Later versions of Android (26+) bundle implementations of the java.time classes. For earlier Android (<26), the process of API desugaring brings a subset of the java.time functionality not originally built into Android. If the desugaring does not offer what you need, the ThreeTenABP project adapts ThreeTen-Backport (mentioned above) to Android. See How to use ThreeTenABP….


一个小测试,展示了如何解析ISO8601中的日期,以及LocalDateTime不能处理DSTs。

 @Test
    public void shouldHandleDaylightSavingTimes() throws ParseException {

        //ISO8601 UTC date format
        SimpleDateFormat utcFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSXXX");

        // 1 hour of difference between 2 dates in UTC happening at the Daylight Saving Time
        Date d1 = utcFormat.parse("2019-10-27T00:30:00.000Z");
        Date d2 = utcFormat.parse("2019-10-27T01:30:00.000Z");

        //Date 2 is before date 2
        Assert.assertTrue(d1.getTime() < d2.getTime());
        // And there is 1 hour difference between the 2 dates
        Assert.assertEquals(1000*60*60, d2.getTime() - d1.getTime());

        //Print the dates in local time
        SimpleDateFormat localFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm z Z", Locale.forLanguageTag("fr_CH"));
        localFormat.setTimeZone(TimeZone.getTimeZone("Europe/Zurich"));

        //Both dates are at 02h30 local time (because of DST), but one is CEST +0200 and the other CET +0100 (clock goes backwards)
        Assert.assertEquals("2019-10-27 02:30 CEST +0200", localFormat.format(d1));
        Assert.assertEquals("2019-10-27 02:30 CET +0100", localFormat.format(d2));

        //Small test that shows that LocalDateTime does not handle DST (and should not be used for storing timeseries data)
        LocalDateTime ld1 = LocalDateTime.ofInstant(d1.toInstant(), ZoneId.of("Europe/Zurich"));
        LocalDateTime ld2 = LocalDateTime.ofInstant(d2.toInstant(), ZoneId.of("Europe/Zurich"));

        //Note that a localdatetime does not handle DST, therefore the 2 dates are the same
        Assert.assertEquals(ld1, ld2);

        //They both have the following local values
        Assert.assertEquals(2019, ld1.getYear());
        Assert.assertEquals(27, ld1.getDayOfMonth());
        Assert.assertEquals(10, ld1.getMonthValue());
        Assert.assertEquals(2, ld1.getHour());
        Assert.assertEquals(30, ld1.getMinute());
        Assert.assertEquals(0, ld1.getSecond());

    }

像这样使用字符串 LocalDate.parse (((String) data.get(“d_iso8601”)),DateTimeFormatter.ISO_DATE)

我很惊讶,甚至没有一个java库支持所有ISO 8601日期格式https://en.wikipedia.org/wiki/ISO_8601。Joda DateTime支持其中大部分,但不是全部,因此我添加了自定义逻辑来处理所有这些。这是我的实现。

import java.text.ParseException; import java.util.Date; import org.apache.commons.lang3.time.DateUtils; import org.joda.time.DateTime; public class ISO8601DateUtils { /** * It parses all the date time formats from https://en.wikipedia.org/wiki/ISO_8601 and returns Joda DateTime. * Zoda DateTime does not support dates of format 20190531T160233Z, and hence added custom logic to handle this using SimpleDateFormat. * @param dateTimeString ISO 8601 date time string * @return */ public static DateTime parse(String dateTimeString) { try { return new DateTime( dateTimeString ); } catch(Exception e) { try { Date dateTime = DateUtils.parseDate(dateTimeString, JODA_NOT_SUPPORTED_ISO_DATES); return new DateTime(dateTime.getTime()); } catch (ParseException e1) { throw new RuntimeException(String.format("Date %s could not be parsed to ISO date", dateTimeString)); } } } private static String[] JODA_NOT_SUPPORTED_ISO_DATES = new String[] { // upto millis "yyyyMMdd'T'HHmmssSSS'Z'", "yyyyMMdd'T'HHmmssSSSZ", "yyyyMMdd'T'HHmmssSSSXXX", "yyyy-MM-dd'T'HHmmssSSS'Z'", "yyyy-MM-dd'T'HHmmssSSSZ", "yyyy-MM-dd'T'HHmmssSSSXXX", // upto seconds "yyyyMMdd'T'HHmmss'Z'", "yyyyMMdd'T'HHmmssZ", "yyyyMMdd'T'HHmmssXXX", "yyyy-MM-dd'T'HHmmss'Z'", "yyyy-MM-dd'T'HHmmssZ", "yyyy-MM-dd'T'HHmmssXXX", // upto minutes "yyyyMMdd'T'HHmm'Z'", "yyyyMMdd'T'HHmmZ", "yyyyMMdd'T'HHmmXXX", "yyyy-MM-dd'T'HHmm'Z'", "yyyy-MM-dd'T'HHmmZ", "yyyy-MM-dd'T'HHmmXXX", //upto hours is already supported by Joda DateTime }; }

Jackson-databind库也有ISO8601DateFormat类可以做到这一点(在ISO8601Utils中实际实现。

ISO8601DateFormat df = new ISO8601DateFormat();
Date d = df.parse("2010-07-28T22:25:51Z");