Unable to parse with DateTimeFormatter [duplicate] - java

This question already has answers here:
How to format LocalDate object to MM/dd/yyyy and have format persist
(4 answers)
Unable to Convert String to localDate with custom pattern [duplicate]
(1 answer)
Closed 1 year ago.
I am trying to parse the date in a specific pattern but every time it is showing date in only format. Here what I am doing. Output is written in comments in front of the line.
String dat = "20-06-2021";
String newFormatLocaleDate = "MMM dd yyyy";
String newFormattedDate = convertToNewFormat(dat,currentFormat,newFormatLocaleDate); //Jun 20 2021
DateTimeFormatter formatter1 = DateTimeFormatter.ofPattern(newFormatLocaleDate);
LocalDate parse1 = java.time.LocalDate.parse(newFormattedDate,formatter1); //2021-06-20
System.out.println("Using parse1 Pattern Only "+parse1); //2021-06-20
Date date1 = java.sql.Date.valueOf(parse1);
System.out.println("Using Date Pattern Only "+date1); //2021-06-20
The pattern in which date is required is given and in the string form it giving the correct value but when I am trying to parse it with LocaleDate it is changing the format for all dates to the above mentioned (yyyy-MM-dd) format irrespective of the newFormatLocaleDate pattern.
Thanks

You should not expect the line
System.out.println("Using parse1 Pattern Only "+parse1);
to output something different than 2021-06-20 it literally is exactly what the docs say what will be out putted.
The output will be in the ISO-8601 format uuuu-MM-dd.
So regardless of the format you used while parsing the LocalDate value the toString method will always output a data in the format uuuu-MM-dd.
If you want a different format use the instance method format.

Please note that you are printing the LocalDate and Date instances (using their toString() implementation), therefore not formatted according to your desired template. If you want to print out your parsed date in a particular format, you need to apply a formatter again, for example like this:
System.out.println(parse1.format(DateTimeFormatter.ofPattern("MMM dd yyyy")))

Related

Java iso 8601 universal date time format [duplicate]

This question already has an answer here:
in java I need define date in this format 1999-05-31T13:20:00-05:00 [duplicate]
(1 answer)
Closed 5 years ago.
I want this result on date time: 2008-10-31T15:07:38.6875000-05:00, please help me how i get this result?
I am using following code but unable to get required response.
TimeZone tzone = TimeZone.getTimeZone("UTC");
DateFormat dateformat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm'Z'");
String nowAsISO = dateformat.format(new Date());
You are quite right:
Your format expression is missing seconds :ss, millisecond .SSS (many S for how many digit you want) and the Z timezone tag without '
Using single quote ' in the expression will exclude everything included in them from parsing, ergo you will have it printed like a string.
TimeZone tzone = TimeZone.getTimeZone("UTC");
DateFormat dateformat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSSSSSZ");
String nowAsISO = dateformat.format(new Date());
You can see every possible pattern here

convert String to date using java 8 and format -> 'uuuu-MM-dd'

I want to convert from string to date using Java 8.
I can easily convert using SimpleDateFormat and yyyy-MM-dd format
String startDate2="2017-03-24";
SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(new java.sql.Date(sdf1.parse(startDate2).getTime()));
output:
2017-03-24
String startDate2="2017-03-24";
SimpleDateFormat sdf1 = new SimpleDateFormat("uuuu-MM-dd");
System.out.println(new java.sql.Date(sdf1.parse(startDate2).getTime()));
But when I use 'uuuu-MM-dd' instead of 'yyyy-MM-dd'
output :
1970-03-24(wrong)
now in Java 8:
String startDate1="2017-03-23";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("uuuu-MM-dd");
But I don't know how I can get the date which would be sql date type same as above correct output.
java.sql.Date has a static valueOf method that takes a Java 8 LocalDate so you can do:
String startDate1 = "2017-03-23";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("uuuu-MM-dd");
LocalDate date = LocalDate.parse(startDate1, formatter);
java.sql.Date sqlDate = java.sql.Date.valueOf(date);
As far as I can see, you have a text in yyyy-MM-dd format and you want it in uuuu-MM-dd format. So you need two formats:
String startDate2="2017-03-24";
SimpleDateFormat sourceFormat = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat targetFormat = new SimpleDateFormat("uuuu-MM-dd");
java.sql.Date date = new java.sql.Date(sourceFormat.parse(startDate2).getTime());
String formattedAsDayOfWeek = targetFormat.format(date);
System.out.println(formattedAsDayOfWeek);
Bottom line is that Date contains a millisecond value. java.sql.Date.toString() uses the yyyy-MM-dd format regardless how you parsed it. java.util.sql.Date uses another format: EEE MMM dd hh:mm:ss zzz yyyy with English Locale.
You can do other formatting with DateFormat -s.
I presume you need the uuuu-MM-dd format for inserting data to the database. What does that logic look like?
You don’t want a java.sql.Date. You want a LocalDate. Your SQL database wants one too.
String startDate2 = "2017-03-24";
LocalDate date = LocalDate.parse(startDate2);
System.out.println(date);
Output is:
2017-03-24
I am exploiting the fact that your string is in ISO 8601 format. The classes of java.time including LocalDate parse this format as their default, that is, without any explicit formatter.
You also note that we don’t need any explicit formatter for formatting back into uuuu-MM-dd format for the output. The toString method implicitly called from System..out.println() produces ISO 8601 format back.
Assuming that you are using a JDBC 4.2 compliant driver (I think we all are now), I am taking the way to pass it on to your SQL database from this question: Insert & fetch java.time.LocalDate objects to/from an SQL database such as H2:
myPreparedStatement.setObject ( 1 , date ); // Automatic detection and conversion of data type.
Refer to the linked question for much more detail.
The java.sql.Date class is poorly designed, a true hack on top of the already poorly designed java.util.Date class. Both classes are long outdated. Don’t use any of them anymore.
One more link: Wikipedia article: ISO 8601

parse String to 'yyyy-mm-ddThh:mm:ss.SSSZ' ISODate java [duplicate]

This question already has answers here:
Java / convert ISO-8601 (2010-12-16T13:33:50.513852Z) to Date object
(4 answers)
Closed 6 years ago.
How to convert String to ISODate format using SimpleDateFormat, which means that i want to finally get Date in java.util.Date format.
My string will look like 2017-02-17T09:28:03.000Z, i want to convert it to date formt. I can do this in Joda date format, but since i am using mongoDB, it does not accept joda format.
String startDateString1 = "2017-02-17T04:23:17.452Z";
DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
Date startDate = df.parse(startDateString1);
String newDateString = df.format(startDate);
above code is not working.
Your code is not working since Z is a reserved character used to interpret RFC-822 time zones :
RFC 822 time zone: For formatting, the RFC 822 4-digit time zone format is used:
RFC822TimeZone:
Sign TwoDigitHours Minutes
TwoDigitHours:
Digit Digit
Since Java 7, you can use X to interpret ISO-8601 time zones https://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html . The following works :
DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSX");
However, on my computer,
System.out.println(newDateString);
results in the following output :
2017-02-17T05:23:17.452+01
Alternatively, if you are sure to have only UTC dates, you could escape the Z letter with simple quotes :
DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
And here is the displayed result :
2017-02-17T04:23:17.452Z
You can do it in Java 8 like below.
Instant instant = Instant.parse("2017-02-17T09:28:03.000Z");
Date date = Date.from(instant);
You could use javax.xml.bind.DatatypeConverter.parseDateTime("2017-02-17T04:23:17.452Z") which will return a Calendar object. You can call getTime() on it to get a Date object.

Parsing String to Date without using SimpleDateFormat?

I am developing a spring application and in one of my controller i have following lines to parse from string to date and format the parsed date to required format. But again i need to parse back formatted string into date without using any SimpleDateFormat, so is it possible to do so ?
SimpleDateFormat dateFormat = new SimpleDateFormat("MM-dd-yyyy");
SimpleDateFormat dateFormat2 = new SimpleDateFormat("yyyy-MM-dd");
Date pick=dateFormat.parse(request.getParameter("pickDate"));
String pick_date=dateFormat2.format(pick);
Edit:
I found in the wikipedia that china has the locale yyyy-MM-dd. check this reference date format by country
set locale to China you'll get the required date format
Try this
String d1="12-27-2010";
Stirng[] splitdata=d1.split("-");
int month=Integer.parseInt(splitdata[0]);
int day=Integer.parseInt(splitdata[1]);
int year=Integer.parseInt(splitdata[2]);
Calender cal=Calender.getInstance(Locale.CHINA);
cal.set(year,month,day);
Date d=cal.getTime();
This should work
If you know your data format you can do that. by using simple string operations
Ex:
if your data format is
MM-dd-yyyy
then you can convert to yyyy-MM-dd like this
String d1="12-27-2010";
Stirng[] splitdata=d1.split("-");
String s2= splitdate[2]+"-"+splitdate[0]+"-"+splitdate[1];
You can use Concatenation Operator(+) for that
Yes possible; just write the code to do the parsing. Should not be that difficult ...

Date Format Confusion

in my App User Selects Date like 2013-01-02
but in MySql DB the column format is like 02-Jan-2013 so want change the Date Format
my code is:
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-mm-dd");
SimpleDateFormat formatter1 = new SimpleDateFormat("dd-mmm-yyyy");
Date start_date = (Date)formatter.parse(GBRF.getStart_date());//GBRF.getStart_date() returns Form Data as 2013-01-02
String dt=formatter1.format(start_date);
Date sd=(Date)formatter1.parse(dt);
at the End sd print Date like this Wed Jan 02 00:01:00 IST 2013
i dont want that format..
just i want like 02-Jan-2013
give me an idea..
Thanks in Advance
You can format Date into String with SimpleDateFormat, after that if you try to print date instance it will invoke toString() method of Date class which has no change in output and you can't alter that output because it is coming from toString() implmentation
Note: in your format you need to use M for month (note capital M)
A Date object does not have a format in itself. It holds just a point in time. The format comes into play when you convert it to or from a String.
Also note that m in the format is used for minutes not months. So you probably want a format like dd-MMM-yyyy.
Try
System.out.println(formatter1.format(sd));
to get the date printed as you like it.
You need to change your date format first :
`SimpleDateFormat formatter1 = new SimpleDateFormat("dd-MMM-yyyy");`
In your case, if you just print dt, it should print date in the required format instead of converting it into Date object again i.e. sd
When you are printing sd, without any formatting it will print the default String implementation of Date object which is exactly what you are seeing as an output

Categories