lit*_*leK 847 java string time date data-conversion
将String"2010年1月2日"格式转换为DateJava 格式的最佳方法是什么？
最终,我希望将月份,日期和年份作为整数分解,以便我可以使用
Date date = new Date();
date.setMonth()..
date.setYear()..
date.setDay()..
date.setlong currentTime = date.getTime();
将日期转换为时间.
Bal*_*usC 1593
这是困难的方法,java.util.Date自Java 1.1(1997)以来,这些setter方法已被弃用.只需SimpleDateFormat使用与输入字符串匹配的格式模式格式化日期.
在您的"2010年1月2日"的特定情况下作为输入字符串:
MMMM模式d模式.yyyy模式.String string = "January 2, 2010";
DateFormat format = new SimpleDateFormat("MMMM d, yyyy", Locale.ENGLISH);
Date date = format.parse(string);
System.out.println(date); // Sat Jan 02 00:00:00 GMT 2010
请注意显式Locale参数的重要性.如果省略它,那么它将使用默认语言环境,该语言环境不一定是输入字符串的月份名称中使用的英语.如果语言环境与输入字符串不匹配,那么java.text.ParseException即使格式模式看起来有效,您也会感到困惑.
以下是javadoc的相关摘录,列出了所有可用的格式模式:
Letter Date or Time Component Presentation Examples
------ ---------------------- ------------------ -------------------------------------
G Era designator Text AD
y Year Year 1996; 96
Y Week year Year 2009; 09
M/L Month in year Month July; Jul; 07
w Week in year Number 27
W Week in month Number 2
D Day in year Number 189
d Day in month Number 10
F Day of week in month Number 2
E Day in week Text Tuesday; Tue
u Day number of week Number 1
a Am/pm marker Text PM
H Hour in day (0-23) Number 0
k Hour in day (1-24) Number 24
K Hour in am/pm (0-11) Number 0
h Hour in am/pm (1-12) Number 12
m Minute in hour Number 30
s Second in minute Number 55
S Millisecond Number 978
z Time zone General time zone Pacific Standard Time; PST; GMT-08:00
Z Time zone RFC 822 time zone -0800
X Time zone ISO 8601 time zone -08; -0800; -08:00
请注意,模式区分大小写,并且基于文本的四个或更多字符的模式表示完整形式; 否则,如果可用,则使用简短或缩写形式.因此,例如MMMMM或更多是不必要的.
以下是SimpleDateFormat解析给定字符串的有效模式的一些示例:
Input string Pattern
------------------------------------ ----------------------------
2001.07.04 AD at 12:08:56 PDT yyyy.MM.dd G 'at' HH:mm:ss z
Wed, Jul 4, '01 EEE, MMM d, ''yy
12:08 PM h:mm a
12 o'clock PM, Pacific Daylight Time hh 'o''clock' a, zzzz
0:08 PM, PDT K:mm a, z
02001.July.04 AD 12:08 PM yyyyy.MMMM.dd GGG hh:mm aaa
Wed, 4 Jul 2001 12:08:56 -0700 EEE, d MMM yyyy HH:mm:ss Z
010704120856-0700 yyMMddHHmmssZ
2001-07-04T12:08:56.235-0700 yyyy-MM-dd'T'HH:mm:ss.SSSZ
2001-07-04T12:08:56.235-07:00 yyyy-MM-dd'T'HH:mm:ss.SSSXXX
2001-W27-3 YYYY-'W'ww-u
一个重要的注意的是,SimpleDateFormat是不是线程安全的.换句话说,您永远不应声明并将其指定为静态或实例变量,然后从不同的方法/线程重用它.您应该始终在方法本地范围内创建全新的.
如果您恰好使用的是Java 8或更高版本,请使用DateTimeFormatter(此处,单击链接以查看所有预定义的格式化程序和可用的格式模式; 此处提供了该教程).这个新API的灵感来自JodaTime.
String string = "January 2, 2010";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMMM d, yyyy", Locale.ENGLISH);
LocalDate date = LocalDate.parse(string, formatter);
System.out.println(date); // 2010-01-02
注意:如果您的格式模式恰好也包含时间部分,那么请使用LocalDateTime#parse(text, formatter)而不是LocalDate#parse(text, formatter).而且,如果您的格式模式恰好也包含时区,那么请ZonedDateTime#parse(text, formatter)改用.
以下是javadoc的相关摘录,列出了所有可用的格式模式:
Symbol Meaning Presentation Examples
------ -------------------------- ------------ ----------------------------------------------
G era text AD; Anno Domini; A
u year year 2004; 04
y year-of-era year 2004; 04
D day-of-year number 189
M/L month-of-year number/text 7; 07; Jul; July; J
d day-of-month number 10
Q/q quarter-of-year number/text 3; 03; Q3; 3rd quarter
Y week-based-year year 1996; 96
w week-of-week-based-year number 27
W week-of-month number 4
E day-of-week text Tue; Tuesday; T
e/c localized day-of-week number/text 2; 02; Tue; Tuesday; T
F week-of-month number 3
a am-pm-of-day text PM
h clock-hour-of-am-pm (1-12) number 12
K hour-of-am-pm (0-11) number 0
k clock-hour-of-am-pm (1-24) number 0
H hour-of-day (0-23) number 0
m minute-of-hour number 30
s second-of-minute number 55
S fraction-of-second fraction 978
A milli-of-day number 1234
n nano-of-second number 987654321
N nano-of-day number 1234000000
V time-zone ID zone-id America/Los_Angeles; Z; -08:30
z time-zone name zone-name Pacific Standard Time; PST
O localized zone-offset offset-O GMT+8; GMT+08:00; UTC-08:00;
X zone-offset 'Z' for zero offset-X Z; -08; -0830; -08:30; -083015; -08:30:15;
x zone-offset offset-x +0000; -08; -0830; -08:30; -083015; -08:30:15;
Z zone-offset offset-Z +0000; -0800; -08:00;
请注意,它有更多流行模式的预定义格式化程序.因此DateTimeFormatter.ofPattern("EEE, d MMM yyyy HH:mm:ss Z", Locale.ENGLISH);,您可以使用DateTimeFormatter.RFC_1123_DATE_TIME.这是可能的,因为它们与SimpleDateFormat线程安全相反.如有必要,您也可以定义自己的.
对于特定的输入字符串格式,您不需要使用显式DateTimeFormatter:标准ISO 8601日期,如2016-09-26T17:44:57Z,可以直接解析,LocalDateTime#parse(text)因为它已经使用了ISO_LOCAL_DATE_TIME格式化程序.同样,LocalDate#parse(text)解析没有时间组件的ISO日期(请参阅参考资料ISO_LOCAL_DATE),并ZonedDateTime#parse(text)解析添加了偏移量和时区的ISO日期(请参阅参考资料ISO_ZONED_DATE_TIME).
pn1*_*ude 72
啊,再次是Java Date的讨论.为了处理日期操作,我们使用Date,Calendar,GregorianCalendar和SimpleDateFormat.例如,使用1月日期作为输入:
Calendar mydate = new GregorianCalendar();
String mystring = "January 2, 2010";
Date thedate = new SimpleDateFormat("MMMM d, yyyy", Locale.ENGLISH).parse(mystring);
mydate.setTime(thedate);
//breakdown
System.out.println("mydate -> "+mydate);
System.out.println("year -> "+mydate.get(Calendar.YEAR));
System.out.println("month -> "+mydate.get(Calendar.MONTH));
System.out.println("dom -> "+mydate.get(Calendar.DAY_OF_MONTH));
System.out.println("dow -> "+mydate.get(Calendar.DAY_OF_WEEK));
System.out.println("hour -> "+mydate.get(Calendar.HOUR));
System.out.println("minute -> "+mydate.get(Calendar.MINUTE));
System.out.println("second -> "+mydate.get(Calendar.SECOND));
System.out.println("milli -> "+mydate.get(Calendar.MILLISECOND));
System.out.println("ampm -> "+mydate.get(Calendar.AM_PM));
System.out.println("hod -> "+mydate.get(Calendar.HOUR_OF_DAY));
然后你可以通过以下方式操纵它:
Calendar now = Calendar.getInstance();
mydate.set(Calendar.YEAR,2009);
mydate.set(Calendar.MONTH,Calendar.FEBRUARY);
mydate.set(Calendar.DAY_OF_MONTH,25);
mydate.set(Calendar.HOUR_OF_DAY,now.get(Calendar.HOUR_OF_DAY));
mydate.set(Calendar.MINUTE,now.get(Calendar.MINUTE));
mydate.set(Calendar.SECOND,now.get(Calendar.SECOND));
// or with one statement
//mydate.set(2009, Calendar.FEBRUARY, 25, now.get(Calendar.HOUR_OF_DAY), now.get(Calendar.MINUTE), now.get(Calendar.SECOND));
System.out.println("mydate -> "+mydate);
System.out.println("year -> "+mydate.get(Calendar.YEAR));
System.out.println("month -> "+mydate.get(Calendar.MONTH));
System.out.println("dom -> "+mydate.get(Calendar.DAY_OF_MONTH));
System.out.println("dow -> "+mydate.get(Calendar.DAY_OF_WEEK));
System.out.println("hour -> "+mydate.get(Calendar.HOUR));
System.out.println("minute -> "+mydate.get(Calendar.MINUTE));
System.out.println("second -> "+mydate.get(Calendar.SECOND));
System.out.println("milli -> "+mydate.get(Calendar.MILLISECOND));
System.out.println("ampm -> "+mydate.get(Calendar.AM_PM));
System.out.println("hod -> "+mydate.get(Calendar.HOUR_OF_DAY));
Rut*_*war 46
String str_date = "11-June-07";
DateFormat formatter;
Date date;
formatter = new SimpleDateFormat("dd-MMM-yy");
date = formatter.parse(str_date);
mic*_*cha 39
使用Java 8,我们获得了一个新的Date/Time API(JSR 310).
以下方法可用于在不依赖Joda-Time的情况下解析Java 8中的日期:
String str = "January 2nd, 2010";
// if we 2nd even we have changed in pattern also it is not working please workout with 2nd
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMMM Q, yyyy", Locale.ENGLISH);
LocalDate date = LocalDate.parse(str, formatter);
// access date fields
int year = date.getYear(); // 2010
int day = date.getDayOfMonth(); // 2
Month month = date.getMonth(); // JANUARY
int monthAsInt = month.getValue(); // 1
LocalDate是用于表示日期(没有时间)的标准Java 8类.如果要解析包含日期和时间信息的值,则应使用LocalDateTime.对于具有时区的值,请使用ZonedDateTime.两者都提供parse()类似于以下的方法LocalDate:
LocalDateTime dateWithTime = LocalDateTime.parse(strWithDateAndTime, dateTimeFormatter);
ZonedDateTime zoned = ZonedDateTime.parse(strWithTimeZone, zoneFormatter);
DateTimeFormatter Javadoc中的列表格式化字符:
All letters 'A' to 'Z' and 'a' to 'z' are reserved as pattern letters.
The following pattern letters are defined:
Symbol Meaning Presentation Examples
------ ------- ------------ -------
G era text AD; Anno Domini; A
u year year 2004; 04
y year-of-era year 2004; 04
D day-of-year number 189
M/L month-of-year number/text 7; 07; Jul; July; J
d day-of-month number 10
Q/q quarter-of-year number/text 3; 03; Q3; 3rd quarter
Y week-based-year year 1996; 96
w week-of-week-based-year number 27
W week-of-month number 4
E day-of-week text Tue; Tuesday; T
e/c localized day-of-week number/text 2; 02; Tue; Tuesday; T
F week-of-month number 3
a am-pm-of-day text PM
h clock-hour-of-am-pm (1-12) number 12
K hour-of-am-pm (0-11) number 0
k clock-hour-of-am-pm (1-24) number 0
H hour-of-day (0-23) number 0
m minute-of-hour number 30
s second-of-minute number 55
S fraction-of-second fraction 978
A milli-of-day number 1234
n nano-of-second number 987654321
N nano-of-day number 1234000000
V time-zone ID zone-id America/Los_Angeles; Z; -08:30
z time-zone name zone-name Pacific Standard Time; PST
O localized zone-offset offset-O GMT+8; GMT+08:00; UTC-08:00;
X zone-offset 'Z' for zero offset-X Z; -08; -0830; -08:30; -083015; -08:30:15;
x zone-offset offset-x +0000; -08; -0830; -08:30; -083015; -08:30:15;
Z zone-offset offset-Z +0000; -0800; -08:00;
Bas*_*que 25
虽然一些答案在技术上是正确的,但它们是不可取的.
关于Joda-Time的几点说明如下.
在Joda-Time中,DateTime对象确实知道自己指定的时区.这与java.util.Date类形成对比,后者似乎有一个时区但没有.
请注意下面的示例代码中我们如何将时区对象传递给解析字符串的格式化程序.该时区用于将该日期时间解释为已在该时区中发生.因此,您需要考虑并确定该字符串输入所代表的时区.
由于输入字符串中没有时间部分,因此Joda-Time会将指定时区的第一时刻指定为时间.通常这意味着00:00:00但不总是因为夏令时(DST)或其他异常.顺便说一下,您可以通过调用对任何DateTime实例执行相同的操作withTimeAtStartOfDay.
格式化程序模式中使用的字符在Joda-Time中与java.util.Date/Calendar中的字符相似,但不完全相同.仔细阅读文档.
我们通常在Joda-Time中使用不可变类.我们不是修改现有的Date-Time对象,而是调用基于另一个对象创建新的实例的方法,复制了大多数方面,除非需要进行更改.一个例子是withZone下面最后一行的调用.不可变性有助于使Joda-Time非常安全,并且可以使一些工作更加清晰.
您将需要java.util.Date对象与其他不了解Joda-Time对象的类/框架一起使用.幸运的是,来回移动非常容易.
从java.util.Date对象(此处命名date)到Joda-Time DateTime ...
org.joda.time.DateTime dateTime = new DateTime( date, timeZone );
从Joda-Time转向java.util.Date对象的另一个方向......
java.util.Date date = dateTime.toDate();
String input = "January 2, 2010";
java.util.Locale locale = java.util.Locale.US;
DateTimeZone timeZone = DateTimeZone.forID( "Pacific/Honolulu" ); // Arbitrarily chosen for example.
DateTimeFormatter formatter = DateTimeFormat.forPattern( "MMMM d, yyyy" ).withZone( timeZone ).withLocale( locale );
DateTime dateTime = formatter.parseDateTime( input );
System.out.println( "dateTime: " + dateTime );
System.out.println( "dateTime in UTC/GMT: " + dateTime.withZone( DateTimeZone.UTC ) );
跑的时候......
dateTime: 2010-01-02T00:00:00.000-10:00
dateTime in UTC/GMT: 2010-01-02T10:00:00.000Z
小智 20
在处理SimpleDateFormat类时,重要的是要记住Date不是线程安全的,并且您不能与多个线程共享一个Date对象.
"m"和"M"之间也有很大的区别,其中小案例用于分钟,大写情况用于月份.与"d"和"D"相同.这可能会导致经常被忽视的细微错误.有关更多详细信息,请参阅Javadoc或Java中将字符串转换为日期的指南.
Lun*_*ong 17
DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
Date date;
try {
date = dateFormat.parse("2013-12-4");
System.out.println(date.toString()); // Wed Dec 04 00:00:00 CST 2013
String output = dateFormat.format(date);
System.out.println(output); // 2013-12-04
}
catch (ParseException e) {
e.printStackTrace();
}
这对我来说可以.
小智 6
我们使用的简单两种格式化程序:
我们解析完整的日期到时间格式:
date="2016-05-06 16:40:32";
public static String setDateParsing(String date) throws ParseException {
// This is the format date we want
DateFormat mSDF = new SimpleDateFormat("hh:mm a");
// This format date is actually present
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-mm-dd hh:mm");
return mSDF.format(formatter.parse(date));
}
我谦虚的测试计划.我使用它来玩我在日志文件中找到的格式化程序和查找长日期(但是谁把它们放在那里......).
我的测试程序:
package be.test.package.time;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.TimeZone;
public class TimeWork {
public static void main(String[] args) {
TimeZone timezone = TimeZone.getTimeZone("UTC");
List<Long> longs = new ArrayList<>();
List<String> strings = new ArrayList<>();
//Formatting a date needs a timezone - otherwise the date get formatted to your system time zone.
//Use 24h format HH. In 12h format hh can be in range 0-11, which makes 12 overflow to 0.
DateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss.SSS");
formatter.setTimeZone(timezone);
Date now = new Date();
//Test dates
strings.add(formatter.format(now));
strings.add("01-01-1970 00:00:00.000");
strings.add("01-01-1970 00:00:01.000");
strings.add("01-01-1970 00:01:00.000");
strings.add("01-01-1970 01:00:00.000");
strings.add("01-01-1970 10:00:00.000");
strings.add("01-01-1970 12:00:00.000");
strings.add("01-01-1970 24:00:00.000");
strings.add("02-01-1970 00:00:00.000");
strings.add("01-01-1971 00:00:00.000");
strings.add("01-01-2014 00:00:00.000");
strings.add("31-12-1969 23:59:59.000");
strings.add("31-12-1969 23:59:00.000");
strings.add("31-12-1969 23:00:00.000");
//Test data
longs.add(now.getTime());
longs.add(-1L);
longs.add(0L); //Long date presentation at - midnight 1/1/1970 UTC - The timezone is important!
longs.add(1L);
longs.add(1000L);
longs.add(60000L);
longs.add(3600000L);
longs.add(36000000L);
longs.add(43200000L);
longs.add(86400000L);
longs.add(31536000000L);
longs.add(1388534400000L);
longs.add(7260000L);
longs.add(1417706084037L);
longs.add(-7260000L);
System.out.println("===== String to long =====");
//Show the long value of the date
for (String string: strings) {
try {
Date date = formatter.parse(string);
System.out.println("Formated date : " + string + " = Long = " + date.getTime());
} catch (ParseException e) {
e.printStackTrace();
}
}
System.out.println("===== Long to String =====");
//Show the date behind the long
for (Long lo : longs) {
Date date = new Date(lo);
String string = formatter.format(date);
System.out.println("Formated date : " + string + " = Long = " + lo);
}
}
}
检测结果:
===== String to long =====
Formated date : 05-12-2014 10:17:34.873 = Long = 1417774654873
Formated date : 01-01-1970 00:00:00.000 = Long = 0
Formated date : 01-01-1970 00:00:01.000 = Long = 1000
Formated date : 01-01-1970 00:01:00.000 = Long = 60000
Formated date : 01-01-1970 01:00:00.000 = Long = 3600000
Formated date : 01-01-1970 10:00:00.000 = Long = 36000000
Formated date : 01-01-1970 12:00:00.000 = Long = 43200000
Formated date : 01-01-1970 24:00:00.000 = Long = 86400000
Formated date : 02-01-1970 00:00:00.000 = Long = 86400000
Formated date : 01-01-1971 00:00:00.000 = Long = 31536000000
Formated date : 01-01-2014 00:00:00.000 = Long = 1388534400000
Formated date : 31-12-1969 23:59:59.000 = Long = -1000
Formated date : 31-12-1969 23:59:00.000 = Long = -60000
Formated date : 31-12-1969 23:00:00.000 = Long = -3600000
===== Long to String =====
Formated date : 05-12-2014 10:17:34.873 = Long = 1417774654873
Formated date : 31-12-1969 23:59:59.999 = Long = -1
Formated date : 01-01-1970 00:00:00.000 = Long = 0
Formated date : 01-01-1970 00:00:00.001 = Long = 1
Formated date : 01-01-1970 00:00:01.000 = Long = 1000
Formated date : 01-01-1970 00:01:00.000 = Long = 60000
Formated date : 01-01-1970 01:00:00.000 = Long = 3600000
Formated date : 01-01-1970 10:00:00.000 = Long = 36000000
Formated date : 01-01-1970 12:00:00.000 = Long = 43200000
Formated date : 02-01-1970 00:00:00.000 = Long = 86400000
Formated date : 01-01-1971 00:00:00.000 = Long = 31536000000
Formated date : 01-01-2014 00:00:00.000 = Long = 1388534400000
Formated date : 01-01-1970 02:01:00.000 = Long = 7260000
Formated date : 04-12-2014 15:14:44.037 = Long = 1417706084037
Formated date : 31-12-1969 21:59:00.000 = Long = -7260000
小智 5
您可以使用SimpleDateformat更改字符串到目前为止
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String strDate = "2000-01-01";
Date date = new Date(sdf.parse(strDate).getTime());