Java string to date conversion
That's the hard way, and those java.util.Date
setter methods have been deprecated since Java 1.1 (1997). Moreover, the whole java.util.Date
class was de-facto deprecated (discommended) since introduction of java.time
API in Java 8 (2014).
Simply format the date using DateTimeFormatter
with a pattern matching the input string (the tutorial is available here).
In your specific case of "January 2, 2010" as the input string:
- "January" is the full text month, so use the
MMMM
pattern for it - "2" is the short day-of-month, so use the
d
pattern for it. - "2010" is the 4-digit year, so use the
yyyy
pattern for it.
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
Note: if your format pattern happens to contain the time part as well, then use LocalDateTime#parse(text, formatter)
instead of LocalDate#parse(text, formatter)
. And, if your format pattern happens to contain the time zone as well, then use ZonedDateTime#parse(text, formatter)
instead.
Here's an extract of relevance from the javadoc, listing all available format patterns:
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; |
Convert String to Date with Milliseconds
The Date class stores the time as milliseconds, and if you look into your date object you will see that it actually has a time of 1598515567413 milliseconds.
You are fooled by the System.out.println() which uses Date's toString() method. This method is using the "EEE MMM dd HH:mm:ss zzz yyyy" format to display the date and simply omits all milliseconds.
If you use your formatter, which has milliseconds in its format string, you will see that the milliseconds are correct:
System.out.println(formatter.format(dateFormatter));
outputs 2020-08-27T10:06:07.413
How can i convert String to Date when it has TRT in it
Where your code failed:
SimpleDateFormat sdf1=new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");
String dateStr = "06.08.2020";
sdf1.parse(dateStr);
As you can see, the pattern of the SimpleDateFormat
and that of the date
string do not match and therefore, this code will throw ParseException
.
How to make it work?
SimpleDateFormat sdf = new SimpleDateFormat("dd.MM.yyyy");
String dateStr = "06.08.2020";
Date date = sdf.parse(dateStr);
You must have already got why it worked. It worked because the pattern of the SimpleDateFormat
matches with that of the dateStr
string.
Can I format the Date
object (i.e. date
) into the original string?
Yes, just use the same format which you used to parse the original string as shown below:
SimpleDateFormat sdf = new SimpleDateFormat("dd.MM.yyyy");
String dateStr = "06.08.2020";
Date date = sdf.parse(dateStr);
// Display in the default format
System.out.println(date);
// Format into the string
dateStr = sdf.format(date);
System.out.println(dateStr);
A piece of advice:
I recommend you switch from the outdated and error-prone java.util
date-time API and SimpleDateFormat
to the modern java.time
date-time API and the corresponding formatting API (package, java.time.format
). Learn more about the modern date-time API from Trail: Date Time.
Using the modern date-time API:
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd.MM.yyyy");
String dateStr = "06.08.2020";
LocalDate date = LocalDate.parse(dateStr, formatter);
// Display in the default format
System.out.println(date);
// Format into the string
dateStr = formatter.format(date);
System.out.println(dateStr);
I don't see any difference using the legacy API and the modern API:
That's true for this simple example but when you will need to do complex operations using date and time, you will find the modern date-time API smart and clean while the legacy API complex and error-prone.
Demo:
import java.time.LocalDateTime;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
public class Main {
public static void main(String[] args) {
// Given date-time string
String strDate = "Thu Aug 06 00:00:00 TRT 2020";
// Replace TRT with standard time-zone string
strDate = strDate.replace("TRT", "Europe/Istanbul");
// Define formatter
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss zzzz yyyy");
// Parse the date-time string into ZonedDateTime
ZonedDateTime zdt = ZonedDateTime.parse(strDate, formatter);
System.out.println(zdt);
// If you wish, convert ZonedDateTime into LocalDateTime
LocalDateTime ldt = zdt.toLocalDateTime();
System.out.println(ldt);
}
}
Output:
2020-08-06T00:00+03:00[Europe/Istanbul]
2020-08-06T00:00
convert string to date without changing timezone in the string using java
Just omit the timezone format from the end of the String (letter Z
).
For example, this will print Thu Nov 12 06:30:00 CET 2020
String s = "2020-11-12T6:30:00-0800";
DateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss");
var date = format.parse(s);
System.out.println(date);
But if I add the letter Z
at the end, it will interpret the given timezone and change time to my local timezone, when printed. So this will print Thu Nov 12 15:30:00 CET 2020
String s = "2020-11-12T6:30:00-0800";
DateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ssZ");
var date = format.parse(s);
System.out.println(date);
More about the patterns can be found in the JavaDoc of SimpleDateFormat.
how to convert java string to Date object
You basically effectively converted your date in a string format to a date object. If you print it out at that point, you will get the standard date formatting output. In order to format it after that, you then need to convert it back to a date object with a specified format (already specified previously)
String startDateString = "06/27/2007";
DateFormat df = new SimpleDateFormat("MM/dd/yyyy");
Date startDate;
try {
startDate = df.parse(startDateString);
String newDateString = df.format(startDate);
System.out.println(newDateString);
} catch (ParseException e) {
e.printStackTrace();
}
Convert String Date to String date different format
SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat format2 = new SimpleDateFormat("dd-MM-yyyy");
Date date = format1.parse("2013-02-21");
System.out.println(format2.format(date));
Java convert string to date not converting correctly
You were using the wrong date format mask. From the documentation, Y
corresponds to the week year, and D
is the day in year.
Try this version:
Date dateCommence = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
.parse("2021-01-06 00:00:00");
System.out.println(dateCommence);
This prints:
Wed Jan 06 00:00:00 CET 2021
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