Java 如何将 Joda-Time DateTime 格式化为只有 mm/dd/yyyy？

How to format Joda-Time DateTime to only mm/dd/yyyy?

提问by iCodeLikeImDrunk

I have a string "11/15/2013 08:00:00", I want to format it to "11/15/2013", what is the correct DateTimeFormatterpattern?

我有一个字符串“ 11/15/2013 08:00:00”，我想将它格式化为“ 11/15/2013”，正确的DateTimeFormatter模式是什么？

I've tried many and googled and still unable to find the correct pattern.

我已经尝试了很多并用谷歌搜索，但仍然无法找到正确的模式。

edit: I am looking for Joda-TimeDateTimeFormatter, not Java's SimpleDateFormat..

编辑：我正在寻找Joda-TimeDateTimeFormatter，而不是 Java 的 SimpleDateFormat ..

采纳答案by DeltaLima

Joda time

乔达时间

Create a DateTimeFormatterusing DateTimeFormat.forPattern(String)

创建一个DateTimeFormatter使用DateTimeFormat.forPattern(String)

Using Joda time you would do it like this:

使用 Joda 时间，您可以这样做：

String dateTime = "11/15/2013 08:00:00";
// Format for input
DateTimeFormatter dtf = DateTimeFormat.forPattern("MM/dd/yyyy HH:mm:ss");
// Parsing the date
DateTime jodatime = dtf.parseDateTime(dateTime);
// Format for output
DateTimeFormatter dtfOut = DateTimeFormat.forPattern("MM/dd/yyyy");
// Printing the date
System.out.println(dtfOut.print(jodatime));

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Standard Java ≥ 8

标准 Java ≥ 8

Java 8 introduced a new Date and Time library, making it easier to deal with dates and times. If you want to use standard Java version 8 or beyond, you would use a DateTimeFormatter. Since you don't have a time zone in your String, a java.time.LocalDateTimeor a LocalDate, otherwise the time zoned varieties ZonedDateTimeand ZonedDatecould be used.

Java 8 引入了一个新的日期和时间库，可以更轻松地处理日期和时间。如果要使用标准 Java 版本 8 或更高版本，则应使用DateTimeFormatter。由于您的String、java.time.LocalDateTime或LocalDate中没有时区，否则可以使用时区变体ZonedDateTime和ZonedDate。

// Format for input
DateTimeFormatter inputFormat = DateTimeFormatter.ofPattern("MM/dd/yyyy HH:mm:ss");
// Parsing the date
LocalDate date = LocalDate.parse(dateTime, inputFormat);
// Format for output
DateTimeFormatter outputFormat = DateTimeFormatter.ofPattern("MM/dd/yyyy");
// Printing the date
System.out.println(date.format(outputFormat));

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Standard Java < 8

标准 Java < 8

Before Java 8, you would use the a SimpleDateFormatand java.util.Date

在 Java 8 之前，您将使用SimpleDateFormat和java.util.Date

String dateTime = "11/15/2013 08:00:00";
// Format for input
SimpleDateFormat dateParser = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
// Parsing the date
Date date7 = dateParser.parse(dateTime);
// Format for output
SimpleDateFormat dateFormatter = new SimpleDateFormat("MM/dd/yyyy");
// Printing the date
System.out.println(dateFormatter.format(date7));

回答by Clad Clad

I have a very dumb but working option. if you have the String fullDate = "11/15/2013 08:00:00";

我有一个非常愚蠢但可行的选择。如果你有 String fullDate = "11/15/2013 08:00:00";

   String finalDate = fullDate.split(" ")[0];

That should work easy and fast. :)

这应该可以轻松快速地工作。:)

回答by The Guy with The Hat

Another way of doing that is:

另一种方法是：

String date = dateAndTime.substring(0, dateAndTime.indexOf(" "));

I'm not exactly certain, but I think this might be faster/use less memory than using the .split()method.

我不确定，但我认为这可能比使用该.split()方法更快/使用更少的内存。

回答by The Guy with The Hat

I think this will work, if you are using JodaTime:

如果您使用 JodaTime，我认为这会起作用：

String strDateTime = "11/15/2013 08:00:00";
DateTime dateTime = DateTime.parse(strDateTime);
DateTimeFormatter fmt = DateTimeFormat.forPattern("MM/dd/YYYY");
String strDateOnly = fmt.print(dateTime);

I got part of this from here.

我从这里得到了一部分。

回答by Eddie

This works

这有效

String x = "22/06/2012";
String y = "25/10/2014";

String datestart = x;
String datestop = y;

//DateTimeFormatter format = DateTimeFormat.forPattern("dd/mm/yyyy");
SimpleDateFormat  format = new SimpleDateFormat("dd/mm/yyyy");

Date d1 = null;
Date d2 = null;

try {
    d1 =  format.parse(datestart);
    d2 = format.parse(datestop);

    DateTime dt1 = new DateTime(d1);
    DateTime dt2 = new DateTime(d2);

    //Period
    period = new Period (dt1,dt2);

    //calculate days
    int days = Days.daysBetween(dt1, dt2).getDays();


} catch (ParseException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

回答by sebastian krüger

DateTime date = DateTime.now().withTimeAtStartOfDay();
date.toString("HH:mm:ss")

回答by Chad Bingham

I am adding this here even though the other answers are completely acceptable. JodaTime has parsers pre built in DateTimeFormat:

即使其他答案是完全可以接受的，我还是在这里添加了这个。JodaTime 在 DateTimeFormat 中预先构建了解析器：

dateTime.toString(DateTimeFormat.longDate());

This is most of the options printed out with their format:

这是打印出的大多数选项及其格式：

shortDate:         11/3/16
shortDateTime:     11/3/16 4:25 AM
mediumDate:        Nov 3, 2016
mediumDateTime:    Nov 3, 2016 4:25:35 AM
longDate:          November 3, 2016
longDateTime:      November 3, 2016 4:25:35 AM MDT
fullDate:          Thursday, November 3, 2016
fullDateTime:      Thursday, November 3, 2016 4:25:35 AM Mountain Daylight Time

回答by Hymany.cheng

UPDATED:

更新：

You can: create a constant:

您可以： 创建一个常量：

private static final DateTimeFormatter DATE_FORMATTER_YYYY_MM_DD =
          DateTimeFormat.forPattern("yyyy-MM-dd"); // or whatever pattern that you need.

This DateTimeFormat is importing from: (be careful with that)

这个 DateTimeFormat 是从以下导入的：（小心）

import org.joda.time.format.DateTimeFormat; import org.joda.time.format.DateTimeFormatter;

导入 org.joda.time.format.DateTimeFormat; 导入 org.joda.time.format.DateTimeFormatter;

Parse the Date with:

解析日期：

DateTime.parse(dateTimeScheduled.toString(), DATE_FORMATTER_YYYY_MM_DD);

Before:
DateTime.parse("201711201515",DateTimeFormat.forPattern("yyyyMMddHHmm")).toString("yyyyMMdd");

之前：
DateTime.parse("201711201515",DateTimeFormat.forPattern("yyyyMMddHHmm")).toString("yyyyMMdd");

if want datetime:

如果想要日期时间：

DateTime.parse("201711201515", DateTimeFormat.forPattern("yyyyMMddHHmm")).withTimeAtStartOfDay();