I'm trying to parse a String into Data, I create the DataParser, in according to date format, the code I wrote is this:
String date_s = "04-May-2017 17:28:27";
DateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss");
Date date;
try {
date = formatter.parse(date_s);
System.out.println(date);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
When I execute this, I got always an exception
java.text.ParseException: Unparseable date: "04-May-2017 17:28:27"
I don't understand why the data is not parsed, someone can help me?
This thread of answers would not be complete without the modern solution. These days you should no longer use Date and SimpleDateFormat, but switch over to the newer date and time classes:
DateTimeFormatter formatter
= DateTimeFormatter.ofPattern("dd-MMM-yyyy HH:mm:ss", Locale.ENGLISH);
LocalDateTime dateTime;
try {
dateTime = LocalDateTime.parse(date_s, formatter);
System.out.println(dateTime);
} catch (DateTimeParseException e) {
System.err.println(e);
}
This prints
2017-05-04T17:28:27
(LocalDateTime.toString() returns ISO 8601 format) If leaving out Locale.ENGLISH, on my computer I get
Text '04-May-2017 17:28:27' could not be parsed at index 3
Index 3 is where it say May, so the message is somewhat helpful.
LocalDateTime and DateTimeFormatter were introduced in Java 8, but have also been backported to Java 6 and 7.
the string you want to parse is local dependent (the word May is English), so the jvm is not able to infer that may is the month of may in English
define the formatter using the constructor qith the locale.
DateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss",Locale.ENGLISH);
You need another constructor with a Locale that supports MMM (May)
DateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss",Locale.US)
or using standard format dd-MM-yyyy with month digits.
(Sorry, in the meantime the answer was already posted)
Related
I wanted to validate date in client side so I wrote the following code. But instead of getting an exception I am getting a proper date object for 31st of February date string, which is clearly an invalid date.
public class Test {
public static void main(String[] args) {
String dateFormat = "HH:mm:ss MM/dd/yyyy";
String dateString = "11:30:59 02/31/2015";
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern(dateFormat, Locale.US);
try {
LocalDateTime date = LocalDateTime.parse(dateString, dateTimeFormatter);
System.out.println(date);
} catch (Exception e) {
// Throw invalid date message
}
}
}
Output : 2015-02-28T11:30:59
Does anyone know why LocalDateTime is parsing this date instead of throwing an exception.
You just need a strict ResolverStyle.
Parsing a text string occurs in two phases. Phase 1 is a basic text parse according to the fields added to the builder. Phase 2 resolves the parsed field-value pairs into date and/or time objects. This style is used to control how phase 2, resolving, happens.
Sample code - where withResolverStyle(ResolverStyle.STRICT) is the important change, along with the use of uuuu rather than yyyy (where uuuu is "year" and "yyyy" is "year of era", and therefore ambiguous):
import java.time.*;
import java.time.format.*;
import java.util.*;
public class Test {
public static void main(String[] args) {
String dateFormat = "HH:mm:ss MM/dd/uuuu";
String dateString = "11:30:59 02/31/2015";
DateTimeFormatter dateTimeFormatter = DateTimeFormatter
.ofPattern(dateFormat, Locale.US)
.withResolverStyle(ResolverStyle.STRICT);
try {
LocalDateTime date = LocalDateTime.parse(dateString, dateTimeFormatter);
System.out.println(date);
} catch (DateTimeParseException e) {
// Throw invalid date message
System.out.println("Exception was thrown");
}
}
}
The Java 8 DateTimeFormatter uses yyyy to mean YEAR_OF_ERA, and uuuu to mean YEAR. You need to modify your pattern string as follows:
String dateFormat = "HH:mm:ss MM/dd/uuuu";
The DateTimeFormatter defaults to using the SMART resolver style, but you want it to use the STRICT resolver style. Modify your dateTimeFormatter initialization code as follows:
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern(dateFormat, Locale.US)
.withResolverStyle(ResolverStyle.STRICT);
It is not rounding down. February has never had 31 days, and it is impossible to use a validating date / time object to represent a day that doesn't exist.
As a result, it takes the invalid input and gives you the best approximation to the correct date (the last date of February that year).
SimpleDateFormat inherits from DateFormat which has a setLenient(boolean value) method on it. I would expect that if you called setLenient(true) prior to parsing, it would probably complain more, as detailed in the javadocs.
try {
SimpleDateFormat df = new java.text.SimpleDateFormat("HH:mm:ss MM/dd/yyyy");
df.setLenient(false);
System.out.println(df.parse("11:30:59 02/29/2015"));
} catch (java.text.ParseException e) {
System.out.println(e);
}
I found one solution to recognize date as a valid date with DateFormat.setLenient(boolean). If you try to parse any invalid date it will throws parse exception.
Edit:
Java 8, but this will raise exception if a month is not between 1 and 12, if a day is more than 32. Exactly not working. But for month its working.
try {
TemporalAccessor ta = DateTimeFormatter.ofPattern("HH:mm:ss MM/dd/yyyy").parse("11:30:59 02/32/2015");
} catch (Exception e) {
System.out.println(e);
}
Output:
java.time.format.DateTimeParseException: Text '11:30:59 02/32/2015' could not be
parsed: Invalid value for DayOfMonth (valid values 1 - 28/31): 32
LocalDateTime.parse will only throw an error if the String passed in contains invalid characters, a number of days exceeding 31 or a month exceeding 12.
For example, if you modified your code as such:
String dateString = "11:30:59 0zz2/31/2015";
an exception would be thrown caused by the invalid 'zz' characters within your given date. As to why it's 'rounding-down' the date so to speak, that I don't know.
Source: https://docs.oracle.com/javase/8/docs/api/java/time/LocalDateTime.html#parse-java.lang.CharSequence-
This question already has answers here:
Parsing ISO-8601 DateTime with offset with colon in Java
(4 answers)
Closed 3 years ago.
I have a date value: - 2019-09-30T00:00:00.000+05:30
I want to convert into the format - dd MMM yyyy
I have the code:
public static String parseDateAndTimeStringCust(String datestring) {
if(datestring.length()>=10){
SimpleDateFormat dateFormat2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
try {
String fDate = new SimpleDateFormat("dd MMM yyyy").format(dateFormat2.parse(datestring));
return fDate;
} catch (ParseException ex) {
ex.printStackTrace();
}
}
return datestring;
}
Analysis:
My dateFormat2 I am using is wrong
Question:
What is the correct data format i have to use so that I can get the
result in the format dd MMM yyyy
What is the proper reference I can use in future to build such date
formats
You should use classes from the java.time package.
This is what you're looking for.
String str = "2019-09-30T00:00:00.000+05:30";
OffsetDateTime dt = OffsetDateTime.parse(str);
String out = dt.format(DateTimeFormatter.ofPattern("dd MMM yyyy"));
System.out.println(out);
Note that the actual output depends on your locale, but then you could supply the Locale as the second argument to DateTimeFormatter.ofPattern.
Also note that the single-argument version of OffsetDateTime.parse implies the ISO_OFFSET_DATE_TIME format.
Furthermore, whether the actual output of abovementioned method is accurate, depends on how you want to handle the timezone offset, i.e. whether you want to convert it to UTC or ignore it. For instance, the timestamp 2019-09-30T00:00:00.000+05:30 actually falls on the 29th of September if converted to UTC (the time is then 2019-09-29T18:30:00.000Z).
DateTimeFormatter
The documentation of the DateTimeFormatter class contains detailed information about the formatting symbols and how they are parsed. There are many predefined formats for well-known and commonly used patterns, for example ISO_OFFSET_DATE_TIME conforming with the ISO 8601 standard.
public static String parseDateAndTimeStringCust(String datestring) {
Date dataFormated = null;
SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy");
try {
dataFormated = dateFormat.parse(datestring);
} catch (ParseException ex) {
ex.printStackTrace();
}
return dataFormated.toString();
}
Try changing following line:
SimpleDateFormat dateFormat2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
To:
SimpleDateFormat dateFormat2 = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss");
I wanted to validate date in client side so I wrote the following code. But instead of getting an exception I am getting a proper date object for 31st of February date string, which is clearly an invalid date.
public class Test {
public static void main(String[] args) {
String dateFormat = "HH:mm:ss MM/dd/yyyy";
String dateString = "11:30:59 02/31/2015";
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern(dateFormat, Locale.US);
try {
LocalDateTime date = LocalDateTime.parse(dateString, dateTimeFormatter);
System.out.println(date);
} catch (Exception e) {
// Throw invalid date message
}
}
}
Output : 2015-02-28T11:30:59
Does anyone know why LocalDateTime is parsing this date instead of throwing an exception.
You just need a strict ResolverStyle.
Parsing a text string occurs in two phases. Phase 1 is a basic text parse according to the fields added to the builder. Phase 2 resolves the parsed field-value pairs into date and/or time objects. This style is used to control how phase 2, resolving, happens.
Sample code - where withResolverStyle(ResolverStyle.STRICT) is the important change, along with the use of uuuu rather than yyyy (where uuuu is "year" and "yyyy" is "year of era", and therefore ambiguous):
import java.time.*;
import java.time.format.*;
import java.util.*;
public class Test {
public static void main(String[] args) {
String dateFormat = "HH:mm:ss MM/dd/uuuu";
String dateString = "11:30:59 02/31/2015";
DateTimeFormatter dateTimeFormatter = DateTimeFormatter
.ofPattern(dateFormat, Locale.US)
.withResolverStyle(ResolverStyle.STRICT);
try {
LocalDateTime date = LocalDateTime.parse(dateString, dateTimeFormatter);
System.out.println(date);
} catch (DateTimeParseException e) {
// Throw invalid date message
System.out.println("Exception was thrown");
}
}
}
The Java 8 DateTimeFormatter uses yyyy to mean YEAR_OF_ERA, and uuuu to mean YEAR. You need to modify your pattern string as follows:
String dateFormat = "HH:mm:ss MM/dd/uuuu";
The DateTimeFormatter defaults to using the SMART resolver style, but you want it to use the STRICT resolver style. Modify your dateTimeFormatter initialization code as follows:
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern(dateFormat, Locale.US)
.withResolverStyle(ResolverStyle.STRICT);
It is not rounding down. February has never had 31 days, and it is impossible to use a validating date / time object to represent a day that doesn't exist.
As a result, it takes the invalid input and gives you the best approximation to the correct date (the last date of February that year).
SimpleDateFormat inherits from DateFormat which has a setLenient(boolean value) method on it. I would expect that if you called setLenient(true) prior to parsing, it would probably complain more, as detailed in the javadocs.
try {
SimpleDateFormat df = new java.text.SimpleDateFormat("HH:mm:ss MM/dd/yyyy");
df.setLenient(false);
System.out.println(df.parse("11:30:59 02/29/2015"));
} catch (java.text.ParseException e) {
System.out.println(e);
}
I found one solution to recognize date as a valid date with DateFormat.setLenient(boolean). If you try to parse any invalid date it will throws parse exception.
Edit:
Java 8, but this will raise exception if a month is not between 1 and 12, if a day is more than 32. Exactly not working. But for month its working.
try {
TemporalAccessor ta = DateTimeFormatter.ofPattern("HH:mm:ss MM/dd/yyyy").parse("11:30:59 02/32/2015");
} catch (Exception e) {
System.out.println(e);
}
Output:
java.time.format.DateTimeParseException: Text '11:30:59 02/32/2015' could not be
parsed: Invalid value for DayOfMonth (valid values 1 - 28/31): 32
LocalDateTime.parse will only throw an error if the String passed in contains invalid characters, a number of days exceeding 31 or a month exceeding 12.
For example, if you modified your code as such:
String dateString = "11:30:59 0zz2/31/2015";
an exception would be thrown caused by the invalid 'zz' characters within your given date. As to why it's 'rounding-down' the date so to speak, that I don't know.
Source: https://docs.oracle.com/javase/8/docs/api/java/time/LocalDateTime.html#parse-java.lang.CharSequence-
Below is my code to parse the date using SimpleDateFormat with pattern:
String pattern = "yyyy-MM-dd";
SimpleDateFormat format = new SimpleDateFormat(pattern);
try {
Date date = format.parse("05-21-2030");
System.out.println(date);
} catch (ParseException e) {
e.printStackTrace();
}
You can see the date which I passed to parse is different from date format which is specified in SimpleDateFormat. In this case I was expecting kind of excpetion as format is different but it parsed successfully with some different date values. I got the output - Tue Mar 22 00:00:00 IST 12
When I pass the same format like 2030-05-21 it works fine.
Can you guys please let me know how can I prevent such things in my code?
Basically you want SimpleDateFormat to be strict, so set lenient to false.
SimpleDateFormat format = new SimpleDateFormat(pattern);
format.setLenient(false);
If you can afford using Java 8 time API, its formatter works as expected:
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
try {
LocalDate date = LocalDate.parse("2030-05-21", formatter);
System.out.println(date);
LocalDate date2 = LocalDate.parse("05-21-2030", formatter);
System.out.println(date2);
} catch (DateTimeParseException e) {
e.printStackTrace();
}
Output:
2030-05-21
java.time.format.DateTimeParseException: Text '05-21-2030' could not be parsed at index 0
at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1947)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1849)
at java.time.LocalDate.parse(LocalDate.java:400)
at java8.Snippet.main(Snippet.java:25)
I am trying to format dates entered by my application user using SimpleDateFormat but I always get an error:
01/28/2014java.text.ParseException: Unparseable date: "01/28/2014"
The code I am using to format the date is as follows:
Date rDate, dDate;
String Date1 = request.getParameter("Date1");
String Date2 = request.getParameter("Date2");
//Here the date get display for example as 01/29/2014 (i.e. MM/DD/YYYY)
System.out.println("Date1:: "+ Date1);
System.out.println("Date2:: "+ Date2);
SimpleDateFormat parseRDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
SimpleDateFormat parseDDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
try {
//#########Crashes in the next two lines#########...
rDate = (Date)parseRDate.parse(Date1);
dDate = (Date)parseDDate.parse(Date2);
} catch (ParseException e) {
e.printStackTrace();
}
Can someone please help me by telling me what I am doing wrong here?
Thanks for your time
You need to match the DateFormat pattern to your input String
SimpleDateFormat parseRDate = new SimpleDateFormat("MM/dd/yyyy");
Any idea how I can convert the format from MM/dd/YYYY to yyyy-MM-dd HH:mm:ss?
All you need to do is use a separate SimpleDateFormat instance for formatting
SimpleDateFormat output = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
System.out.println(output.format(date1));
As you say, Date1 is of the form MM/dd/yyyy... but you're trying to parse it with a format of yyyy-MM-dd HH:mm:ss.
The pattern you parse to the SimpleDateFormat constructor has to match the format of the data itself. (What did you think you were specifying in the constructor?)
Note that the code you've provided isn't doing and formatting at all - just parsing.
You should also work out which time zone you're interested in, and which Locale. Personally I think it's clearer to specify both of those explicitly - even if you want the system default ones.
(If you're doing any significant amount of date/time work, you should also consider using Joda Time, which is a much more pleasant date/time API. I'd also consider more useful exception handling, and following Java naming conventions...)
You specify the format yyyy-MM-dd HH:mm:ss in the constructor and then accept a completely different format (MM/dd/yyyy) as input. You need to make the actual format match the expected format.
Examine the following (for comparison):
Date rDate, dDate;
SimpleDateFormat parseRDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
SimpleDateFormat parseDDate = new SimpleDateFormat("MM/dd/yyyy");
try {
rDate = (Date)parseRDate.parse("2014-01-28 12:22:22");
dDate = (Date)parseDDate.parse("01/28/2014");
} catch (ParseException e) {
e.printStackTrace();
}
The string passed to the constructor is what tells SimpleDateFormat how to read the input you give it later.