In this tutorial, we will show you how to convert a String to java.util.Date
. Many Java beginners are stuck in the Date conversion, hope this summary guide will helps you in some ways.
// String -> Date
SimpleDateFormat.parse(String);
// Date -> String
SimpleDateFormat.format(date);
Refer to table below for some of the common date and time patterns used in java.text.SimpleDateFormat
, refer to this JavaDoc
Letter | Description | Examples |
y | Year | 2013 |
M | Month in year | July, 07, 7 |
d | Day in month | 1-31 |
E | Day name in week | Friday, Sunday |
a | Am/pm marker | AM, PM |
H | Hour in day | 0-23 |
h | Hour in am/pm | 1-12 |
m | Minute in hour | 0-60 |
s | Second in minute | 0-60 |
Note
You may interest at this Java 8 example – How to convert String to LocalDate
1. String = 7-Jun-2013
If 3 ‘M’, then the month is interpreted as text (Mon-Dec), else number (01-12).
TestDateExample1.java
package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class TestDateExample1 {
public static void main(String[] argv) {
SimpleDateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy");
String dateInString = "7-Jun-2013";
try {
Date date = formatter.parse(dateInString);
System.out.println(date);
System.out.println(formatter.format(date));
} catch (ParseException e) {
e.printStackTrace();
}
}
}
Output
Fri Jun 07 00:00:00 MYT 2013
07-Jun-2013
2. String = 07/06/2013
TestDateExample2.java
package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class TestDateExample2 {
public static void main(String[] argv) {
SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
String dateInString = "07/06/2013";
try {
Date date = formatter.parse(dateInString);
System.out.println(date);
System.out.println(formatter.format(date));
} catch (ParseException e) {
e.printStackTrace();
}
}
}
Output
Fri Jun 07 00:00:00 MYT 2013
07/06/2013
3. String = Fri, June 7 2013
TestDateExample3.java
package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class TestDateExample3 {
public static void main(String[] argv) {
SimpleDateFormat formatter = new SimpleDateFormat("E, MMM dd yyyy");
String dateInString = "Fri, June 7 2013";
try {
Date date = formatter.parse(dateInString);
System.out.println(date);
System.out.println(formatter.format(date));
} catch (ParseException e) {
e.printStackTrace();
}
}
}
Output
Fri Jun 07 00:00:00 MYT 2013
Fri, Jun 07 2013
4. String = Friday, Jun 7, 2013 12:10:56 PM
TestDateExample4.java
package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class TestDateExample4 {
public static void main(String[] argv) {
SimpleDateFormat formatter = new SimpleDateFormat("EEEE, MMM dd, yyyy HH:mm:ss a");
String dateInString = "Friday, Jun 7, 2013 12:10:56 PM";
try {
Date date = formatter.parse(dateInString);
System.out.println(date);
System.out.println(formatter.format(date));
} catch (ParseException e) {
e.printStackTrace();
}
}
}
Output
Fri Jun 07 12:10:56 MYT 2013
Friday, Jun 07, 2013 12:10:56 PM
5. String = 2014-10-05T15:23:01Z
Z suffix means UTC, java.util.SimpleDateFormat
doesn’t parse it correctly, you need to replace the suffix Z with ‘+0000’.
TestDateExample5.java
package com.mkyong.date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class TestDateExample5 {
public static void main(String[] argv) {
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ");
String dateInString = "2014-10-05T15:23:01Z";
try {
Date date = formatter.parse(dateInString.replaceAll("Z$", "+0000"));
System.out.println(date);
System.out.println("time zone : " + TimeZone.getDefault().getID());
System.out.println(formatter.format(date));
} catch (ParseException e) {
e.printStackTrace();
}
}
}
Output
Sun Oct 05 23:23:01 MYT 2014
time zone : Asia/Kuala_Lumpur
2014-10-05T23:23:01+0800
In Java 8, you can convert it into a java.time.Instant
object, and display it with a specified time zone.
TestDateExample6.java
package com.mkyong.date;
import java.time.*;
public class TestDateExample6 {
public static void main(String[] argv) {
String dateInString = "2014-10-05T15:23:01Z";
Instant instant = Instant.parse(dateInString);
System.out.println(instant);
//get date time only
LocalDateTime result = LocalDateTime.ofInstant(instant, ZoneId.of(ZoneOffset.UTC.getId()));
System.out.println(result);
//get date time + timezone
ZonedDateTime zonedDateTime = instant.atZone(ZoneId.of("Africa/Tripoli"));
System.out.println(zonedDateTime);
//get date time + timezone
ZonedDateTime zonedDateTime2 = instant.atZone(ZoneId.of("Europe/Athens"));
System.out.println(zonedDateTime2);
}
}
Output
2014-10-05T15:23:01Z
2014-10-05T15:23:01
2014-10-05T17:23:01+02:00[Africa/Tripoli]
2014-10-05T18:23:01+03:00[Europe/Athens]
6.String = 2019/4/1 13:00:00 PM
String d = "2019/4/1 13:00:00 PM";
DateTimeFormatter builder = DateTimeFormat.forPattern("yyyy/MM/dd HH:mm:ss a").withLocale(Locale.ENGLISH);
System.out.println(builder.parseDateTime(d).toString("yyyy-MM-dd HH:mm:ss"));
output:
2019/4/1 13:00:00
References
- SimpleDateFormat JavaDoc
- Java 8 – How to convert String to LocalDate
- Stackoverflow : simpledateformat parsing date with ‘Z’ literal
- Wikipedia : ISO 8601
- Time Zone and Offset Classes
- GMT VS UTC
- What is a Time Zone?
- Joda Time
来源:oschina
链接:https://my.oschina.net/u/2391658/blog/3123068