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String to Date Conversion mm/dd/yy to YYYY-MM-DD in java [duplicate]

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Java Date Error
(8 answers)
Closed 4 years ago.
I want to convert String values in the format of mm/dd/yy to YYYY-MM-DD Date. how to do this conversion?
The input parameter is: 03/01/18
Code to convert String to Date is given below
public static Date stringToDateLinen(String dateVlaue) {
Date date = null;
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
try {
date = formatter.parse(dateVlaue);
} catch (ParseException e) {
e.printStackTrace();
}
return date;
}
When tried to convert using this method it shows the following error
java.text.ParseException: Unparseable date: "03/01/18"

As you say the input is in a different format, first convert the String to a valid Date object. Once you have the Date object you can format it into different types , as you want, check.
To Convert as Date,
SimpleDateFormat formatter = new SimpleDateFormat("MM/dd/yy");
date = formatter.parse(dateVlaue);
To Print it out in the other format,
SimpleDateFormat formatter1 = new SimpleDateFormat("yyyy-MM-dd");
dateString = formatter1.format(date)

You are writing it the wrong way. In fact, for the date you want to convert, you need to write
SimpleDateFormat formatter = new SimpleDateFormat("MM/dd/yy");

The format you are passing to SimpleDateFormat is ("yyyy-MM-dd") which expects date to be in form 2013-03-01 and hence the error.
You need to supply the correct format that you are passing your input as something like below
public static Date stringToDateLinen(String dateVlaue) {
Date date = null;
SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yy");
try {
date = formatter.parse(dateVlaue);
} catch (ParseException e) {
e.printStackTrace();
}
return date;
}

The solution for the above problem
Convert the String date value in the Format of "dd/mm/yy" to Date.
By using the converted Date can able to frame the required date format.
The method has given below
public static String stringToDateLinen(String dateVlaue) {
Date date = null;
SimpleDateFormat formatter = new SimpleDateFormat("dd/mm/yy");
String dateString = null;
try {
// convert to Date Format From "dd/mm/yy" to Date
date = formatter.parse(dateVlaue);
// from the Converted date to the required format eg : "yyyy-MM-dd"
SimpleDateFormat formatter1 = new SimpleDateFormat("yyyy-MM-dd");
dateString = formatter1.format(date);
} catch (ParseException e) {
e.printStackTrace();
}
return dateString;
}

EDIT: Your question said “String values in the format of mm/dd/yy”, but I understand from your comments that you meant “my input format is dd/mm/yy as string”, so I have changed the format pattern string in the below code accordingly. Otherwise the code is the same in both cases.
public static Optional<LocalDate> stringToDateLinen(String dateValue) {
DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("dd/MM/yy");
try {
return Optional.of(LocalDate.parse(dateValue, dateFormatter));
} catch (DateTimeParseException dtpe) {
return Optional.empty();
}
}
Try it:
stringToDateLinen("03/01/18")
.ifPresentOrElse(System.out::println,
() -> System.out.println("Could not parse"));
Output:
2018-01-03
I recommend you stay away from SimpleDateFormat. It is long outdated and notoriously troublesome too. And Date is just as outdated. Instead use LocalDate and DateTimeFormatter from java.time, the modern Java date and time API. It is so much nicer to work with. A LocalDate is a date without time of day, so this suites your requirements much more nicely than a Date, which despite its name is a point in time. LocalDate.toString() produces exactly the format you said you desired (though the LocalDate doesn’t have a format in it).
My method interprets your 2-digit year as 2000-based, that is, from 2000 through 2099. Please think twice before deciding that this is what you want.
What would you want to happen if the string cannot be parsed into a valid date? I’m afraid that returning null is a NullPointerException waiting to happen and a subsequent debugging session to track down the root cause. You may consider letting the DateTimeParseException be thrown out of your method (just declare that in Javadoc) so the root cause is in the stack trace. Or even throw an AssertionError if the situation is not supposed to happen. In my code I am returning an Optional, which clearly signals to the caller that there may not be a result, which (I hope) prevents any NullPointerException. In the code calling the method I am using the ifPresentOrElse method introduced in Java 9. If not using Java 9 yet, use ifPresent and/or read more about using Optional elsewhere.
What went wrong in your code?
The other answers are correct: Your format pattern string used for parsing needs to match the input (not your output). The ParseException was thrown because the format pattern contained hyphens and the input slashes. It was good that you got the exception because another problem is that the order of year, month and day doesn’t match, neither does the number of digits in the year.
Link
Oracle tutorial: Date Time explaining how to use java.time.

Convert "mm/yy" to "yyyy-mm-dd" in java

I need to convert "11/17" string date (November 2017) to "2017-11-01" (November 1, 2017).
What is the best way to achieve this in Java?
I tried:
String dayMonthYear = "11/17";
dayMonthYear = "01/" + dayMonthYear;
DateTimeFormatter formatter = DateTimeFormat.forPattern("dd/MM/yy");
DateTime dt = formatter.parseDateTime(dayMonthYear);
dt.year().setCopy(dt.getYear() + 2000);
DateTimeFormatter dtfOut = DateTimeFormat.forPattern("yyyy-MM-dd");
dayMonthYear = dtfOut.print(dt);
System.out.println(dayMonthYear); // "2017-11-01";
And:
SimpleDateFormat dateFormatTwoDigitsYear = new SimpleDateFormat(TWO_DIGITS_YEAR_DATE_FORMAT); //"dd/MM/yy"
SimpleDateFormat dateFormatFourDigitsYear = new SimpleDateFormat(FOUR_DIGITS_YEAR_DATE_FORMAT);// "yyyy-MM-dd"
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.YEAR, -100);//??? I AM NOT SURE WHY DO I NEEED THIS??
dateFormatTwoDigitsYear.set2DigitYearStart(calendar.getTime());
try
{
dayMonthYear = dateFormatFourDigitsYear.format(dateFormatTwoDigitsYear.parse(dayMonthYear));
}
catch (ParseException e)
{
log.error("Error while formatting date in yyyy-MM-dd format. Date is " + dayMonthYear);
}
I am not sure why I need this line in second appproach:
calendar.add(Calendar.YEAR, -100);
Both of them are working. But I am not sure if there is better solution.

You don't need to add values to the year. The 2 digit value (17) is automatically ajusted to 2017. Also, there's no need to append day 1 in the input. When the day is not present, SimpleDateFormat automatically sets to 1:
// input format: MM/yy
SimpleDateFormat parser = new SimpleDateFormat("MM/yy");
// output format: yyyy-MM-dd
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(formatter.format(parser.parse("11/17"))); // 2017-11-01
PS: if you need to set to another day (other than 1), you can set the date to a Calendar and change it before formatting:
// parse the date
Date date = parser.parse("11/17");
// set to a Calendar
Calendar cal = Calendar.getInstance();
cal.setTime(date);
// change to whatever day you want
cal.set(Calendar.DAY_OF_MONTH, whateverDayIwant);
// format it
System.out.println(formatter.format(cal.getTime()));
Joda-Time
The old classes (Date, Calendar and SimpleDateFormat) have lots of problems and design issues, and they're being replaced by the new APIs.
I've seen you're using Joda-Time, so here's how to do it with this API.
In Joda-Time, when you parse to a DateTime, it sets default values for all the missing fields (in this case, day, hour, minute, etc). But this API has lots of other types that can suit best for each use case.
As the input has only month and year, you can parse it to a org.joda.time.YearMonth and then set the day to 1. This will create a org.joda.time.LocalDate, which can be printed directly (as the toString() method already returns the date in the format you want):
DateTimeFormatter parser = DateTimeFormat.forPattern("MM/yy");
// parse to YearMonth
YearMonth ym = YearMonth.parse("11/17", parser);
// set day to 1
System.out.println(ym.toLocalDate(1)); // 2017-11-01
I prefer this approach because you can set it to whatever day you want, and don't need to create a full DateTime object with fields that you don't need/care about (such as hour, minutes, etc).
If you need to store this value in a String, just call the toString() method:
// store "2017-11-01" in a String
String output = ym.toLocalDate(1).toString();
The format yyyy-MM-dd is the default used by toString(). If you need a different format, you can pass it to toString():
// convert to another format (example: dd/MM/yyyy)
String output = ym.toLocalDate(1).toString("dd/MM/yyyy"); // 01/11/2017
Or you can use another DateTimeFormatter:
// convert to another format (example: dd/MM/yyyy)
DateTimeFormatter fmt = DateTimeFormat.forPattern("dd/MM/yyyy");
String output = fmt.print(ym.toLocalDate(1)); // 01/11/2017
PS: dt.year().setCopy returns a new object, and as you don't assign it to any variable, this value is lost - this method doesn't change the original DateTime object, so dt is not changed by its line of code.
Java new date/time API
Joda-Time is in maintainance mode and is being replaced by the new APIs, so I don't recommend start a new project with it. Even in joda's website it says: "Note that Joda-Time is considered to be a largely “finished” project. No major enhancements are planned. If using Java SE 8, please migrate to java.time (JSR-310).".
If you can't (or don't want to) migrate from Joda-Time to the new API, you can ignore this section.
If you're using Java 8, consider using the new java.time API. It's easier, less bugged and less error-prone than the old APIs.
If you're using Java 6 or 7, you can use the ThreeTen Backport, a great backport for Java 8's new date/time classes. And for Android, you'll also need the ThreeTenABP (more on how to use it here).
The code below works for both.
The only difference is the package names (in Java 8 is java.time and in ThreeTen Backport (or Android's ThreeTenABP) is org.threeten.bp), but the classes and methods names are the same.
The code is very similar to Joda-Time (the API's are not exactly the same, but they have lots of similarities). You can use a Java 8's java.time.format.DateTimeFormatter and parse the input to a java.time.YearMonth (or, in Java 7's ThreeTen Backport, use a org.threeten.bp.format.DateTimeFormatter and parse to a org.threeten.bp.YearMonth):
DateTimeFormatter parser = DateTimeFormatter.ofPattern("MM/yy");
YearMonth ym = YearMonth.parse("11/17", parser);
System.out.println(ym.atDay(1)); // 2017-11-01
If you need to store this value in a String, just call the toString() method:
// store "2017-11-01" in a String
String output = ym.atDay(1).toString();
The format yyyy-MM-dd is the default used by toString(). If you need a different format, you can use another DateTimeFormatter:
// convert to another format (example: dd/MM/yyyy)
DateTimeFormatter fmt = DateTimeFormatter.ofPattern("dd/MM/yyyy");
String output = fmt.format(ym.atDay(1)); // 01/11/2017

You can define two utility methods one converting the string to date and the other converting it back to string.
static Date stringToDate(String string) throws ParseException
{
DateFormat dateFormat = new SimpleDateFormat("MM/yyyy");
return dateFormat.parse(string);
}
static String dateToString(Date date)
{
DateFormat outputFormatter = new SimpleDateFormat("yyyy-MM-dd");
return outputFormatter.format(date);
}
static String formatString(String string)
{
return dateToString(stringToDate(string));
}
//Just call formatString() with your argument
You can combine them if you only intend to convert the first string type to the second type but I like to keep them separate in case I need a date object from string or string directly from a date object.

String Date Java

// Im new to java programming
I have a String object that represents a date/time in this format : "2013-06-09 14:20:00" (yyyy-MM-dd HH:mm:ss)
I want to convert it to a Date object so i can perform calculations on it but im confused on how to do this.
I tried :
String string = "2013-06-09 14:20:00";
Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(string);
System.out.println(date);
//Prints Mon Dec 31 00:00:00 GMT 2012
Any help appreciated
Ok so I have now updated my code to as follows i'm getting the correct date/time now when I print the date but is this the correct implementation :
DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String string = "2013-06-09 14:20:00";
Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(string);
System.out.println(dateFormat.format(date));
//prints 2013-06-09 14:20:00
Thx to everyone that's answered/commented thus far

The format is wrong. Use this instead:
"yyyy-dd-MM HH:mm:ss"
Indeed your last program version is ok, except you don't need to declare the SimpleDateFormat twice. Simply:
DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String string = "2013-06-09 14:20:00";
Date date = dateFormat.parse(string);
System.out.println(dateFormat.format(date));

String string = "2013-06-09 14:20:00";
and the DATE object format is "yyyy-dd-MM HH:mm:ss"
You can get Date,Day,month and many more by using Date object which is present in
java.util.Date package , like as follows.
Date d = new Date(string);
This will call constructor of Date object for which you are passing 'string' variable which contains date.
d.getDay(); // retrieve day on that particular day
d.getDate(); // retrieve Date
and many more are avaiable like this.

Using java.util.Date
The answer by zzKozak is correct. Well, almost correct. The example code omits required exception handling. Like this…
java.text.DateFormat dateFormat = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String string = "2013-06-09 14:20:00";
Date date = null;
try {
date = dateFormat.parse(string);
} catch ( ParseException e ) {
e.printStackTrace();
}
System.out.println("date: " + dateFormat.format(date));
Don't Use java.util.Date!
Avoid using java.util.Date & Calendar classes bundled with Java. They are notoriously bad in both design and implementation.
Instead use a competent date-time library. In Java that means either:
The third-party open-source Joda-Time
In the forthcoming Java 8, the new java.time.* classes defined by JSR 310 and inspired by Joda-Time.
Time Zone
Your question and code fail to address the issue of time zones. If you ignore time zones, you'll get defaults. That may cause unexpected behaviors when deployed in production. Better practice is to always specify a time zone.
Formatter
If you replace a space with a 'T' per the standard ISO 8601 format, then you can conveniently feed that string directly to a constructor of a Joda-Time DateTime instance.
If you must use that string as-is, then define a formatter to specify that format. You can find many examples of that here on StackOverflow.com.
Example Code
Here is some example code using Joda-Time 2.3, running in Java 7.
I arbitrarily chose a time zone of Montréal.
// © 2013 Basil Bourque. This source code may be used freely forever by anyone taking full responsibility for doing so.
// import org.joda.time.*;
// import org.joda.time.format.*;
// Specify a time zone rather than rely on default.
// Necessary to handle Daylight Saving Time (DST) and other anomalies.
DateTimeZone timeZone = DateTimeZone.forID( "America/Montreal" );
DateTime dateTime = new DateTime( "2013-06-09T14:20:00", timeZone ); // Or pass DateTimeZone.UTC as time zone for UTC/GMT.
System.out.println( "dateTime: " + dateTime );
When run…
dateTime: 2013-06-09T14:20:00.000-04:00

java create date object using a value string

I am using this to get the current time :
java.util.Calendar cal = java.util.Calendar.getInstance();
System.out.println(new java.text.SimpleDateFormat("EEEE, dd/MM/yyyy/hh:mm:ss")
.format(cal.getTime()));
I want to put the value (which I print it) into a date object, I tried this:
Date currentDate = new Date(value);
but eclipse tells me that this function is not good.
Edit
the value is the value that I printed to you using system.out.println

Whenever you want to convert a String to Date object then use SimpleDateFormat#parse
Try to use
String dateInString = new java.text.SimpleDateFormat("EEEE, dd/MM/yyyy/hh:mm:ss")
.format(cal.getTime())
SimpleDateFormat formatter = new SimpleDateFormat("EEEE, dd/MM/yyyy/hh:mm:ss");
Date parsedDate = formatter.parse(dateInString);
.Additional thing is if you want to convert a Date to String then you should use SimpleDateFormat#format function.Now the Point for you is
new Date(String) is deprecated and not recommended now.Now whenever anyone wants to parse , then he/she should use SimpleDateFormat#parse.
refer the official doc for more Date and Time Patterns used in SimpleDateFormat options.

Use SimpleDateFormat parse method:
import java.text.DateFormat;
import java.text.SimpleDateFormat;
String inputString = "11-11-2012";
DateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy");
Date inputDate = dateFormat.parse(inputString, dateFormat );
Since we have Java 8 with LocalDate I would suggest use next:
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
String inputString = "11-11-2012";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd-MM-yyyy");
LocalDate inputDate = LocalDate.parse(inputString,formatter);

import java.util.Date;
import java.text.SimpleDateFormat;
Above is the import method, below is the simple code for Date
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = new Date();
system.out.println((dateFormat.format(date)));

FIRST OF ALL KNOW THE REASON WHY ECLIPSE IS DOING SO.
Date has only one constructor Date(long date) which asks for date in long data type.
The constructor you are using
Date(String s)
Deprecated. As of JDK version 1.1, replaced by DateFormat.parse(String s).
Thats why eclipse tells that this function is not good.
See this official docs
http://docs.oracle.com/javase/6/docs/api/java/util/Date.html
Deprecated methods from your context -- Source -- http://www.coderanch.com/t/378728/java/java/Deprecated-methods
There are a number of reasons why a method or class may become deprecated. An API may not be easily extensible without breaking backwards compatibility, and thus be superseded by a more powerful API (e.g., java.util.Date has been deprecated in favor of Calendar, or the Java 1.0 event model). It may also simply not work or produce incorrect results under certain circumstances (e.g., some of the java.io stream classes do not work properly with some encodings). Sometimes an API is just ill-conceived (SingleThreadModel in the servlet API), and gets replaced by nothing. And some of the early calls have been replaced by "Java Bean"-compatible methods (size by getSize, bounds by getBounds etc.)
SEVRAL SOLUTIONS ARE THERE JUST GOOGLE IT--
You can use date(long date) By converting your date String into long milliseconds and stackoverflow has so many post for that purpose.
converting a date string into milliseconds in java

Try this :-
try{
String valuee="25/04/2013";
Date currentDate =new SimpleDateFormat("dd/MM/yyyy").parse(valuee);
System.out.println("Date is ::"+currentDate);
}catch(Exception e){
System.out.println("Error::"+e);
e.printStackTrace();
}
Output:-
Date is ::Thu Apr 25 00:00:00 GMT+05:30 2013
Your value should be proper format.
In your question also you have asked for this below :-
Date currentDate = new Date(value);
This style of date constructor is already deprecated.So, its no more use.Being we know that Date has 6 constructor.Read more

Here is the optimized solution to do it with SimpleDateFormat parse() method.
SimpleDateFormat formatter = new SimpleDateFormat(
"EEEE, dd/MM/yyyy/hh:mm:ss");
String strDate = formatter.format(new Date());
try {
Date pDate = formatter.parse(strDate);
} catch (ParseException e) { // note: parse method can throw ParseException
e.printStackTrace();
}
Few things to notice
We don't need to create a Calendar instance to get the current date
& time instead use new Date()
Also it doesn't require 2 instances of SimpleDateFormat as
found in the most voted answer for this question. It's just a
waste of memory
Furthermore, catching a generic exception like Exception is a bad practice when we know that the parse method only stands a chance to throw a ParseException. We need to be as specific as possible when dealing with Exceptions. You can refer, throws Exception bad practice?

try this, it worked for me.
String inputString = "01-01-1900";
Date inputDate= null;
try {
inputDate = new SimpleDateFormat("dd-MM-yyyy").parse(inputString);
} catch (ParseException e) {
e.printStackTrace();
}
dp.getDatePicker().setMinDate(inputDate.getTime());

It is because value coming String (Java Date object constructor for getting string is deprecated)
and Date(String) is deprecated.
Have a look at jodatime or you could put #SuppressWarnings({“deprecation”}) outside the method calling the Date(String) constructor.

What you're basically trying to do is this:-
Calendar cal = Calendar.getInstance();
Date date = cal.getTime();
The reason being, the String which you're printing is just a String representation of the Date in your required format. If you try to convert it to date, you'll eventually end up doing what I've mentioned above.
Formatting Date(cal.getTime()) to a String and trying to get back a Date from it - makes no sense. Date has no format as such. You can only get a String representation of that using the SDF.

different date format in java after fetching from oracle

In my db max date is as : 27-FEB-12
when i am fetching data by java from db that is:
select to_char(max(CREATE_DT),'dd-mm-yyyy') from PROFILE_DETAILS;
gives me 2012-02-27 00:00:00.0
How can i convert it to: 27-FEB-12( i am trying to use indian date format)
Any idea please

I don't know why you need to_char function in your query. If you are fetching data by jdbc, oracle could give you Date object. It is in your case much easier to convert into different format (String) in future.
anyway based on your current requirement, with to_char, you get a String 2012-02-27 00:00:00.0. now you want to get another string 27-FEB-12. you could do something like below(exception handling was omitted):
final String s = "2012-02-27 00:00:00.0";
String newDateString = new SimpleDateFormat("dd-MMM-yy").format(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S").parse(s));
this will give you 27-Feb-12

String strDate = "2012-02-27 00:00:00.0";
String TimeZoneIds = TimeZone.getDefault().getID();
SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss.S");
SimpleDateFormat sdf2 = new SimpleDateFormat("dd-MMM-yyyy");
sdf2.setTimeZone(TimeZone.getTimeZone(TimeZoneIds));
try {
Date date = sdf1.parse(strDate);
String strFinalDate = sdf2.format(date);
System.out.println(strFinalDate);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

In an Oracle DATE column there is no format; the string representation you see when you select max(create_dt)) from profile_details in SQL*Plus, say, is using an implicit format mask from your NLS settings, which appears to be DD-MON-RR in that client.
You JDBC call is applying an explicit format mask, which is the right thing to do if you want Java to treat it as a String, not least because it may have different NLS settings. But your mask doesn't match what you say you want; you're specifying DD-MM-YYYY when you want DD-MON-RR.
But it also looks like you're probably retrieving the value from the JDBC call with a getDate() call, and it's being implicitly cast back to a Java Date object type. If you want to treat it as a Date in Java, then you don't need the to_char in your select, and you need to use Java tools (e.g. SimpleDateFormat as #Andrew Logvinov suggests) to turn it into a String as needed. If you're only ever treating it as a String - for immediate display, say - then use getString() instead, and fix your date format mask in the query.
Edit
If you retrieve the value from JDBC with getDate() and want to see the value as a String in the format you specified, you need to do something like:
Date raw_date;
String string_date;
SimpleDateFormat sdf = new SimpleDateFormat("dd-MMM-yy");
raw_date = <resultSet>.getDate(1);
string_date = sdf.format(raw_date);

select to_char(max(CREATE_DT),'dd-MON-yy') from PROFILE_DETAILS;