SimpleDateFormat vs DateTimeFormatter - java

I have a use case where I have to compare 2 string dates such as
final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(dateFormat.parse("2019-07-07").compareTo(dateFormat.parse("2019-07-07 23:59:59"))>0);
The above statement using SimpleDateFormat works perfectly fine, now I try doing it using DateTimeFormatter
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
System.out.println( LocalDate.parse("2019-07-07", formatter).compareTo(LocalDate.parse("2019-07-07 23:59:59", formatter))>=0);
This fails with exception:-
Exception in thread "main" java.time.format.DateTimeParseException: Text '2019-07-07 23:59:59' could not be parsed, unparsed text found at index 10
at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1952)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
at java.time.LocalDate.parse(LocalDate.java:400)
at com.amazon.payrollcalculationengineservice.builder.EmployeeJobDataBuilder.main(EmployeeJobDataBuilder.java:226)
How can I avoid this using DateTimeFormatter, the Strings which I pass as input can be in any format like yyyy-mm-dd or yyyy-mm-dd hh:mm:ss , I dont want to write explicitly checks for format , so can I do using DateTimeFormatter as I am able to do this using the SimpleDateFormat library.

You can use [] to specify an optional part of the pattern:
DateTimeFormatter.ofPattern("yyyy-MM-dd[ HH:mm:ss]");
Alternatively, use the overload of parse that takes a ParsePosition, which won't try to parse the entire string if not necessary.
var formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
var localDate = LocalDate.from(formatter.parse("2019-07-07 23:59:59", new ParsePosition(0)))

Related

error java.time.format.DateTimeParseException: Text '2020-10-16T18:04:59+0300' could not be parsed at index 24

I´m trying to pase the next String using LocalDateTime, but I always get de unparsed text found error:
java.time.format.DateTimeParseException: Text '2020-10-16T18:04:59+0300' could not be parsed at index 24
Need: from 2020-10-16T18:04:59+0300 to 2020-10-16 18:04.
My code:
public String getFormattingData(String sourceData) {
DateTimeFormatter sourceFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssZ''e", Locale.ENGLISH);
DateTimeFormatter newFormatter = DateTimeFormatter.ofPattern("dd-MM-yyy HH:mm", Locale.ENGLISH);
LocalDate date = LocalDate.parse("2020-10-16T18:04:59+0300", sourceFormatter);
return newFormatter.format(date);
}
What am I doing wrong?
See the related question: Format a date using the new date time API
The source format you are looking for is: "yyyy-MM-dd'T'HH:mm:ssZ" (as mentioned by #Sweeper in his comment)
If you want the HH:mm in the output format, you need to use a LocalDateTime rather than a LocalDate
The code below works for me:
public String getFormattingData(String sourceData) {
DateTimeFormatter sourceFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssZ", Locale.ENGLISH);
DateTimeFormatter newFormatter = DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm", Locale.ENGLISH);
LocalDateTime date = LocalDateTime.parse("2020-10-16T18:04:59+0300", sourceFormatter);
return newFormatter.format(date);
result:
16-10-2020 18:04
You just need to correct the date pattern of source date like this:
public static String formatDate(String strDate, String srcPattern, String tgtPattern) {
DateTimeFormatter srcFormatter = DateTimeFormatter.ofPattern(srcPattern, Locale.ENGLISH);
DateTimeFormatter tgtFormatter = DateTimeFormatter.ofPattern(tgtPattern, Locale.ENGLISH);
return tgtFormatter.format(LocalDateTime.parse(strDate, srcFormatter));
}
You can also use SimpleDateFormat:
public static String formatDate(String strDate, String srcPattern,
String tgtPattern) throws ParseException {
SimpleDateFormat srcFormatter = new SimpleDateFormat(srcPattern, Locale.ENGLISH);
SimpleDateFormat tgtFormatter = new SimpleDateFormat(tgtPattern, Locale.ENGLISH);
return tgtFormatter.format(srcFormatter.parse(strDate));
}
And then call it with any pattern that you want:
System.out.println(formatDate("2020-10-16T18:04:59+0300", "yyyy-MM-dd'T'HH:mm:ssZ", "dd-MM-yyy HH:mm"));
Don’t write a method that converts a date and time from a string in one format to a string in a different format. In your program keep dates and times as proper date-time objects. Just like you don’t keep numbers and Boolean values in strings (I hope!) When you receive string input, parse into a date-time object at once. Only when you need to give string output, format into an appropriate string.
When I receive a string containing date, time and UTC offset, like yours does, I prefer to parse it into a OffsetDateTime so I get all the information. It’s easier to throw unneeded information away later than to invent the information that we neglected to parse. Also a LocalDate will not work for your purpose since it doesn’t contain time of day. So you cannot format one into 2020-10-16 18:04 format.
For parsing your string I would use:
DateTimeFormatter formatter = new DateTimeFormatterBuilder()
.append(DateTimeFormatter.ISO_LOCAL_DATE)
.appendLiteral('T')
.append(DateTimeFormatter.ISO_LOCAL_TIME)
.appendOffset("+HHmm", "Z")
.toFormatter();
String sourceData = "2020-10-16T18:04:59+0300";
OffsetDateTime dateTime = OffsetDateTime.parse(sourceData, formatter);
System.out.println(dateTime);
Output is:
2020-10-16T18:04:59+03:00
The definition of the formatter is longish but has the advantage of reusing predefined formatters for date and time.
For displaying a formatted date and time to the user, don’t you want to use the user’s time zone rather then the offset that happened to be in the string (+03:00 in your case)?
ZoneId zone = ZoneId.of("Antarctica/South_Pole");
DateTimeFormatter newFormatter = DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm", Locale.ENGLISH);
String formatted = dateTime.atZoneSameInstant(zone).format(newFormatter);
System.out.println(formatted);
17-10-2020 04:04
What went wrong in your code?
As others have said, yyyy-MM-dd'T'HH:mm:ssZ in your format pattern string for parsing parses your entire date-time string of 2020-10-16T18:04:59+0300 nicely. The ''e at the end of the format pattern is the culprit. This would require an additional single quote (apostrophe) and the number of the day of the week to be present (pattern letter e is for localized day of week). Since Java had successfully parsed 24 chars and then failed to parse an apostrophe, it threw the exception mentioning thst the string could not be parsed at index 24.

java.time.format.DateTimeParseException for dd-MMM-yy format

I am trying for hours now to parse this String to LocalDate and I just can't find where my pattern is wrong.
public void parseDate() {
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd'-'MMM'-'yy");
LocalDate date = LocalDate.parse("05-Sep-20", formatter);
}
I get the following exception:
java.time.format.DateTimeParseException: Text '05-Sep-20' could not be parsed at index 3
It works fine when using the pattern dd'-'MMMM'-'yy or dd'-'MM'-'yy, but it just won't work for MMM
I used the single quotes around the dash, because otherwise I was getting a parsing exception at a different index.
I am using Java1.8 and java.time
It could be your locale. Try this:
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd'-'MMM'-'yy", Locale.US);
LocalDate date = LocalDate.parse("05-Sep-20", formatter);
ref: https://stackoverflow.com/a/44928297

Java String to Date object of the format “MM/dd/yyyy HH:mm:ss a”

I need to convert a String containing a date into a date object.
The String will be in the format "yyyy-mm-dd HH:mm:ss" and I want the "MM/dd/yyyy HH:mm:ss a " format as result.
String dateString = "2018-03-20 09:31:31";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MM/dd/yyyy HH:mm:ss a",
Locale.ENGLISH);
LocalDate date = LocalDate.parse(dateString , formatter);
The code above is throwing an exception.
You have to use two Formatter, one to covert String to LocalDateTime and the other to format this date as you want :
From String to LocalDateTime :
String dateString = "2018-03-20 09:31:31";
LocalDateTime date = LocalDateTime.parse(
dateString,
DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss", Locale.ENGLISH)
);
Now From LocalDateTime to String :
DateTimeFormatter formatter = DateTimeFormatter.ofPattern(
"MM/dd/yyyy HH:mm:ss a", Locale.ENGLISH
);
String newDate = date.format(formatter);
System.out.println(newDate);// 03/20/2018 09:31:31 AM
Note : You have to use LocalDateTime instead of just LocalDate, your format contain both date and time, not just date, else you will get an error :
java.time.temporal.UnsupportedTemporalTypeException: Unsupported field: HourOfDay
That's a common error, based on the misconception that dates have formats - but they actually don't.
Date/time objects have only values, and those values - usually numerical - represent the concept of a date (a specific point in the calendar) and a time (a specific moment of the day).
If you have a String, then you don't actually have a date. You have a text (a sequence of characters) that represents a date. Note that all of the strings below are different (they have a different sequence of characters), but all represent the same date (the same values, the same point in the calendar):
2018-03-20 09:31:31
03/20/2018 9:31:31 AM (using USA's format: month/day/year)
Tuesday, March 20th 2018, 09:31:31 am
and many others...
What you want to do is to get one format (one String, one text representing a date) and transform it to another format (anoter String, another different sequence of characters that represents the same date).
In Java (and in many other languages - if not all - btw) you must do it in 2 steps:
convert the String to a date/time object (convert the text to the numerical values) - that's what the parse method does
convert the date/time object to another format (convert the numerical values to another text)
That said, when you call the parse method, you're trying to transform a String (a text, a sequence of characters) into a date/time object. This means that the DateTimeFormatter must have a pattern that matches the input.
The input is 2018-03-20 09:31:31, which is year-month-day hour:minute:second. And the formatter you used to parse it has the pattern MM/dd/yyyy HH:mm:ss a (month/day/year hour:minute:second am/pm).
You used the output pattern (the one that should be used in step 2) to parse the input. That's why you've got an exception: the formatter tried to parse a month with 2 digits followed by a / when the input actually contains a year with 4 digits followed by a -.
You must use a different DateTimeFormatter for each step, using the correct pattern for each case. YCF_L's answer has the code that does the job, I'd just like to add one little detail. The formatter used for the output (step 2) is:
DateTimeFormatter formatter = DateTimeFormatter.ofPattern(
"MM/dd/yyyy HH:mm:ss a", Locale.ENGLISH
);
Note that HH is used for the hours. Take a look at the javadoc and you'll see that uppercase HH represents the hour-of-day fields (values from 0 to 23 - so 1 AM is printed as 01 and 1 PM is printed as 13).
But you're also printing the AM/PM field (the a in the pattern), so maybe what you need is actually the lowercase hh, which is the clock-hour-of-am-pm (values from 1 to 12) or even KK (hour-of-am-pm (values from 0 to 11)).
String dateString = "2018-03-20 09:31:31";
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
try {
Date date = formatter.parse(dateInString);
DateFormat df = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
String reportDate = df.format(date );
} catch (ParseException e) {
e.printStackTrace();
}
You need to do a 2 steps conversion:
from your String date time in the wrong format to a (tempoary) LocalDateTime object.
if you still want to only extract the date (Year-Month-day) do a LocalDateTime.toLocalDate()
From this LocalDateTime object into the your String object in the right format
String dateString = "2018-03-20 09:31:31";
DateTimeFormatter formatterForWrongFormat = new DateTimeFormatterBuilder()
.append(DateTimeFormatter.ISO_LOCAL_DATE)
.appendLiteral(" ")
.append(DateTimeFormatter.ISO_LOCAL_TIME)
.toFormatter();
//1- from String(wrong format) into datetime object
LocalDateTime dateTime = LocalDateTime.parse(dateString , formatterForWrongFormat);
// 1.1 extract date object (Optional)
LocalDate myDate = dateTime.toLocalDate();
// 2- now from your LocalDateTime to the String in the RIGHT format
DateTimeFormatter formatterForRightFormat = DateTimeFormatter.ofPattern("MM/dd/yyyy HH:mm:ss a",
Locale.ENGLISH);
System.out.println("right format: "+dateTime.format(formatterForRightFormat));
you can test this code here
You can use the SimpleDateFormatter which is easier to implement and permit you to change the format of your date easily.
More here : What are the date formats available in SimpleDateFormat class?
Hope this will help you !

Parsing timestamp with timezone in java?

I'm trying to parse a string of format timestamp with timezone obtained from a DB. The String is as follows :
SimpleDateFormat mdyFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSSSZ");
SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy");
Date d1 = mdyFormat.parse("2014-04-01 15:19:49.31146+05:30");
String mdx = sdf.format(d1);
System.out.println(mdx);
Problem is, I get an error saying :
Exception in thread "main" java.text.ParseException: Unparseable date: "2014-04-01 15:19:49.31146+05:30"
at java.text.DateFormat.parse(DateFormat.java:357)
at com.karthik.Timestampvalidate.main(Timestampvalidate.java:31)
Does anyone know how to fix this ?
You need to use X instead of Z:
SimpleDateFormat mdyFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSSSX");
See the javadoc for more info.
Note: only available in Java 7+.
If you get to use the new JSR 310 date/time APIs in Java 8, you can use the XXX format to parse the timezone. You need three Xs to get the specific colon-separated offset that you're using.
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSSSXXX");
TemporalAccessor dateTime = formatter.parse("2014-04-01 15:19:49.31146+05:30");
// returns: {OffsetSeconds=19800},ISO resolved to 2014-04-01T15:19:49.311460

convert string into date format in java

I want to convert this string to the following date format.
String s = "2-26-2013";
Date date = new SimpleDateFormat("EEEE, MMMM/dd/yyyy").parse(s);
System.out.println(date);
I'm getting this error:
Exception in thread "main" java.text.ParseException: Unparseable date: "2-26-2013"
at java.text.DateFormat.parse(DateFormat.java:357)
Well yes. The argument you pass into the constructor of SimpleDateFormat says the format you expect the date to be in.
"EEEE, MMMM/dd/yyyy" would be valid for input like "Tuesday, February/26/2013". It's not even slightly valid for "2-26-2013". You do understand that you're parsing the text at the moment, not formatting it?
It looks like you want a format string of "M-dd-yyyy" or possibly "M-d-yyyy".
If you're trying to convert from one format to another, you need to first specify the format to parse, and then specify the format to format with:
SimpleDateFormat parser = new SimpleDateFormat("M-dd-yyyy");
SimpleDateFormat formatter = new SimpleDateFormat("EEEE, MMMM/dd/yyyy");
Date date = parser.parse(input);
String output = formatter.format(date);
Date date = new SimpleDateFormat("MM-dd-yyyy").parse(s);
The argument to SimpleDateFormat defines the format your date it in. The above line matches your format, and works. Your example does not match.
Instead of using MMMM/dd/yyyy you need to used MM-dd-yyyy. SimpleDateFormat expects the pattern to match what its trying to parse.

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