如何在 Java 中以 YYYY-MM-DD HH:MI:Sec.Millisecond 格式获取当前时间？
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How to get the current time in YYYY-MM-DD HH:MI:Sec.Millisecond format in Java?
提问by Sunil Kumar Sahoo
The code below gives me the current time. But it does not tell anything about milliseconds.
下面的代码给了我当前的时间。但它没有说明任何关于毫秒的信息。
public static String getCurrentTimeStamp() {
SimpleDateFormat sdfDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//dd/MM/yyyy
Date now = new Date();
String strDate = sdfDate.format(now);
return strDate;
}
I get date in the format 2009-09-22 16:47:08(YYYY-MM-DD HH:MI:Sec).
我以2009-09-22 16:47:08(YYYY-MM-DD HH:MI:Sec)格式获取日期。
But I want to retrieve the current time in the format 2009-09-22 16:47:08.128((YYYY-MM-DD HH:MI:Sec.Ms)- where 128 tells the millisecond.
但我想以格式2009-09-22 16:47:08.128((YYYY-MM-DD HH:MI:Sec.Ms)-检索当前时间，其中 128 表示毫秒。
SimpleTextFormatwill work fine. Here the lowest unit of time is second, but how do I get millisecond as well?
SimpleTextFormat会正常工作。这里最低的时间单位是秒，但我如何获得毫秒？
采纳答案by JayJay
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
回答by Michael Borgwardt
You only have to add the millisecond field in your date format string:
您只需在日期格式字符串中添加毫秒字段：
new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
The API doc of SimpleDateFormatdescribes the format string in detail.
SimpleDateFormat的API 文档详细描述了格式字符串。
回答by duggu
try this:-
尝试这个：-
http://docs.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html
http://docs.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss.SSS");
Date date = new Date();
System.out.println(dateFormat.format(date));
or
或者
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();
System.out.println(dateFormat.format(cal.getTime()));
回答by Basil Bourque
tl;dr
tl;博士
Instant.now()
.toString()
2016-05-06T23:24:25.694Z
2016-05-06T23:24:25.694Z
ZonedDateTime
.now
(
ZoneId.of( "America/Montreal" )
)
.format( DateTimeFormatter.ISO_LOCAL_DATE_TIME )
.replace( "T" , " " )
2016-05-06 19:24:25.694
2016-05-06 19:24:25.694
java.time
时间
In Java 8 and later, we have the java.timeframework built into Java 8 and later. These new classes supplant the troublesome old java.util.Date/.Calendar classes. The new classes are inspired by the highly successful Joda-Timeframework, intended as its successor, similar in concept but re-architected. Defined by JSR 310. Extended by the ThreeTen-Extraproject. See the Tutorial.
在 Java 8 及更高版本中，我们在 Java 8 及更高版本中内置了java.time框架。这些新类取代了麻烦的旧 java.util.Date/.Calendar 类。新类的灵感来自非常成功的Joda-Time框架，作为其继承者，概念相似但重新构建。由JSR 310定义。由ThreeTen-Extra项目扩展。请参阅教程。
Be aware that java.time is capable of nanosecondresolution (9 decimal places in fraction of second), versus the millisecondresolution (3 decimal places) of both java.util.Date & Joda-Time. So when formatting to display only 3 decimal places, you could be hiding data.
请注意，java.time 具有纳秒分辨率（以秒为单位的9 个小数位），而java.util.Date 和 Joda-Time的毫秒分辨率（3 个小数位）则不同。因此，当格式化为仅显示 3 个小数位时，您可能隐藏了数据。
If you want to eliminate any microseconds or nanoseconds from your data, truncate.
如果要从数据中消除任何微秒或纳秒，请截断。
Instant instant2 = instant.truncatedTo( ChronoUnit.MILLIS ) ;
The java.time classes use ISO 8601format by default when parsing/generating strings. A Zat the end is short for Zulu, and means UTC.
java.time 类在解析/生成字符串时默认使用ISO 8601格式。Z末尾的A是 , 的缩写Zulu，表示UTC。
An Instantrepresents a moment on the timeline in UTC with resolution of up to nanoseconds. Capturing the current momentin Java 8 is limited to milliseconds, with a new implementation in Java 9 capturing up to nanoseconds depending on your computer's hardware clock's abilities.
AnInstant代表 UTC 时间轴上的一个时刻，分辨率高达纳秒。在 Java 8 中捕获当前时刻仅限于毫秒，而 Java 9 中的新实现可以根据计算机硬件时钟的能力捕获最多纳秒。
Instant instant = Instant.now (); // Current date-time in UTC.
String output = instant.toString ();
2016-05-06T23:24:25.694Z
2016-05-06T23:24:25.694Z
Replace the Tin the middle with a space, and the Zwith nothing, to get your desired output.
用T空格替换中间的 ，而Z什么也没有，以获得您想要的输出。
String output = instant.toString ().replace ( "T" , " " ).replace( "Z" , "" ; // Replace 'T', delete 'Z'. I recommend leaving the `Z` or any other such [offset-from-UTC][7] or [time zone][7] indicator to make the meaning clear, but your choice of course.
2016-05-06 23:24:25.694
2016-05-06 23:24:25.694
As you don't care about including the offset or time zone, make a "local" date-time unrelated to any particular locality.
由于您不关心包括偏移量或时区，因此请制作与任何特定地点无关的“本地”日期时间。
String output = LocalDateTime.now ( ).toString ().replace ( "T", " " );
Joda-Time
乔达时间
The highly successful Joda-Time library was the inspiration for the java.time framework. Advisable to migrate to java.time when convenient.
非常成功的 Joda-Time 库是 java.time 框架的灵感来源。建议在方便时迁移到 java.time。
The ISO 8601format includes milliseconds, and is the default for the Joda-Time2.4 library.
在ISO 8601的格式包含毫秒，对于默认的乔达时间2.4库。
System.out.println( "Now: " + new DateTime ( DateTimeZone.UTC ) );
When run…
运行时…
Now: 2013-11-26T20:25:12.014Z
Also, you can ask for the milliseconds fraction-of-a-second as a number, if needed:
此外，如果需要，您可以要求将毫秒分数作为一个数字：
int millisOfSecond = myDateTime.getMillisOfSecond ();
回答by Joram
A Java one liner
一个 Java one liner
public String getCurrentTimeStamp() {
return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").format(new Date());
}
in JDK8 style
JDK8 风格
public String getCurrentLocalDateTimeStamp() {
return LocalDateTime.now()
.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS"));
}
回答by ttb
To complement the above answers, here is a small working example of a program that prints the current time and date, including milliseconds.
为了补充上述答案，这里是一个打印当前时间和日期（包括毫秒）的程序的小工作示例。
import java.text.SimpleDateFormat;
import java.util.Date;
public class test {
public static void main(String argv[]){
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
Date now = new Date();
String strDate = sdf.format(now);
System.out.println(strDate);
}
}
回答by Android Dev
You can simply get it in the format you want.
您可以简单地以您想要的格式获取它。
String date = String.valueOf(android.text.format.DateFormat.format("dd-MM-yyyy", new java.util.Date()));
回答by Usagi Miyamoto
I would use something like this:
我会使用这样的东西：
String.format("%tF %<tT.%<tL", dateTime);
Variable dateTimecould be any date and/or time value, see JavaDoc for Formatter.
变量dateTime可以是任何日期和/或时间值，请参阅JavaDoc forFormatter.
回答by prime
The easiest way was to (prior to Java 8) use,
最简单的方法是（在 Java 8 之前）使用，
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
But SimpleDateFormatis not thread-safe. Neither java.util.Date. This will lead to leading to potential concurrency issues for users. And there are many problems in those existing designs. To overcome these now in Java 8 we have a separate package called java.time. This Java SE 8 Date and Timedocument has a good overview about it.
但SimpleDateFormat不是线程安全的。既不是java.util.Date。这将导致用户面临潜在的并发问题。而那些现有的设计存在很多问题。为了在 Java 8 中克服这些问题，我们有一个名为java.time的单独包。这个Java SE 8 日期和时间文档有一个很好的概述。
So in Java 8 something like below will do the trick (to format the current date/time),
所以在 Java 8 中，像下面这样的东西会起作用（格式化当前日期/时间），
LocalDateTime.now()
.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS"));
And one thing to note is it was developed with the help of the popular third party library joda-time,
需要注意的一件事是它是在流行的第三方库joda-time的帮助下开发的，
The project has been led jointly by the author of Joda-Time (Stephen Colebourne) and Oracle, under JSR 310, and will appear in the new Java SE 8 package java.time.
该项目由 Joda-Time 的作者（Stephen Colebourne）和 Oracle 联合领导，在 JSR 310 下，并将出现在新的 Java SE 8 包 java.time 中。
But now the joda-timeis becoming deprecated and asked the users to migrate to new java.time.
但是现在已经joda-time过时了，并要求用户迁移到新的java.time.
Note that from Java SE 8 onwards, users are asked to migrate to java.time (JSR-310) - a core part of the JDK which replaces this project
请注意，从 Java SE 8 开始，要求用户迁移到 java.time (JSR-310) - JDK 的核心部分，它取代了这个项目
Anyway having said that,
话虽这么说，
If you have a Calendarinstance you can use below to convert it to the new java.time,
如果您有一个Calendar实例，您可以使用下面的方法将其转换为新的java.time，
Calendar calendar = Calendar.getInstance();
long longValue = calendar.getTimeInMillis();
LocalDateTime date =
LocalDateTime.ofInstant(Instant.ofEpochMilli(longValue), ZoneId.systemDefault());
String formattedString = date.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS"));
System.out.println(date.toString()); // 2018-03-06T15:56:53.634
System.out.println(formattedString); // 2018-03-06 15:56:53.634
If you had a Date object,
如果你有一个 Date 对象，
Date date = new Date();
long longValue2 = date.getTime();
LocalDateTime dateTime =
LocalDateTime.ofInstant(Instant.ofEpochMilli(longValue2), ZoneId.systemDefault());
String formattedString = dateTime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS"));
System.out.println(dateTime.toString()); // 2018-03-06T15:59:30.278
System.out.println(formattedString); // 2018-03-06 15:59:30.278
If you just had the epoch milliseconds,
如果你只有纪元毫秒，
LocalDateTime date =
LocalDateTime.ofInstant(Instant.ofEpochMilli(epochLongValue), ZoneId.systemDefault());
回答by ejaenv
The doc in Java 8 names it fraction-of-second, while in Java 6 was named millisecond. This brought me to confusion
