I know how to use file.lastModified();.
When I println that I get (for example): Sat Mar 17 09:24:33 GMT+01:00 2012.
But is it possible that I only get the day, month and year as numbers, for example: 17 03 2012
Is their a way to do this, maybe a filter, or an other function to get last modified date in numbers?
is file a java.io.File object?
lastModified should return time in milliseconds. You can create a Date object with the lastModified return value and the format the output with a SimpleDateFormat
Date date = new Date(file.lastModified());
System.out.println(date);
SimpleDateFormat sdf = new SimpleDateFormat("d M y");
System.out.println(sdf.format(date));
You can use SimpleDateFormat class, i.e.
package com.example.file;
import java.io.File;
import java.text.SimpleDateFormat;
public class GetFileLastModifiedExample
{
public static void main(String[] args)
{
File file = new File("\\somefile.txt");
System.out.println("Before Format : " + file.lastModified());
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
System.out.println("After Format : " + sdf.format(file.lastModified()));
}
}
Try this,
long longDate = file.lastModified();
Date date = new Date(longDate);
SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy");
String newDate = formatter.format(date);
System.out.println("Formatted date " + newDate);
according to the documentation
File.lastModifed()
should return a long value representing the time the file was last modified, measured in milliseconds since the epoch. Yon can use the long value in conjunction with Calendar
Calendar rightNow = Calendar.getInstance()
rightNow.setTimeInMillis(longValue)
and use rightNow.get(...)
to retrive day, month and year
Related
Let's have the following:
Date inDbDate = null;
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
inDbDate = sdf.parse("2015-09-27 23:24:28.035");
Now, when I output the inDbDate I receive the following:
Sun Sep 27 23:24:28 EEST 2015
So, If I have two dates with millisecond differences, there would be no way to find out or to display it.
How do I compare two Dates with this format - 2015-09-27 23:24:28.035 ?
If you want to compare two Date variables, there are some methods provided after(), before(), equals().
private void someMethod(){
final String dateFormat = "yyyy-MM-dd HH:mm:ss.SSS";
Date firstDate = new Date();
Date secondDate = new Date();
SimpleDateFormat sdf = new SimpleDateFormat(dateFormat);
try {
firstDate = sdf.parse("2015-09-27 23:24:28.035");
secondDate = sdf.parse("2015-09-27 23:24:28.036");
} catch (ParseException pe) {
pe.getMessage();
}
if(firstDate.after(secondDate)) {
System.out.println("The first date is after the second date");
} else{
System.out.println("The first date is before the second date");
}
}
You can copy and paste the above method into your IDE, then try changing the time in the Date variables and see what the outcome is as well as changing the check performed in the if statement.
If you look at the values in one of the Date objects in your debugger you can see the milliseconds are there, just not shown when printed out in a certain format.
1/ you should parse inDbDate with date format ==> inDbDate = sdf.parse("2015-11-11 23:24:28.035");
2/ you can now compare the two dates
if (inDbDate.compareTo(new Date()) > 0) {
System.out.println("inDbDate is after the current date !!");
}
3/ if you want to display, you format it
System.out.println("current time = " + sdf.format(new Date()));
i have written this code to convert the current system date and time to some other timezone. I am not getting any error but i am not getting my output as expected. Like if i execute my program at a particular time.. My output is ::
The current time in India is :: Fri Feb 24 16:09:23 IST 2012
The date and time in :: Central Standard Time is :: Sat Feb 25 03:39:23 IST 2012
And the actual Time according to CST time zone is ::
Friday, 24 February 4:39:16 a.m(GMT - 6:00)
So there's some time gap. and i don't know why this is happening. Any help will be appreciated.. The code is ::
package MyPackage;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
public class Temp2 {
public static void main(String[] args) {
try {
Calendar currentdate = Calendar.getInstance();
String strdate = null;
DateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
strdate = formatter.format(currentdate.getTime());
TimeZone obj = TimeZone.getTimeZone("CST");
formatter.setTimeZone(obj);
//System.out.println(strdate);
//System.out.println(formatter.parse(strdate));
Date theResult = formatter.parse(strdate);
System.out.println("The current time in India is :: " +currentdate.getTime());
System.out.println("The date and time in :: "+ obj.getDisplayName() + "is ::" + theResult);
} catch (ParseException e) {
e.printStackTrace();
}
}
}
It's over the web. Could have googled. Anyways, here is a version for you (shamelessly picked and modified from here):
Calendar calendar = Calendar.getInstance();
TimeZone fromTimeZone = calendar.getTimeZone();
TimeZone toTimeZone = TimeZone.getTimeZone("CST");
calendar.setTimeZone(fromTimeZone);
calendar.add(Calendar.MILLISECOND, fromTimeZone.getRawOffset() * -1);
if (fromTimeZone.inDaylightTime(calendar.getTime())) {
calendar.add(Calendar.MILLISECOND, calendar.getTimeZone().getDSTSavings() * -1);
}
calendar.add(Calendar.MILLISECOND, toTimeZone.getRawOffset());
if (toTimeZone.inDaylightTime(calendar.getTime())) {
calendar.add(Calendar.MILLISECOND, toTimeZone.getDSTSavings());
}
System.out.println(calendar.getTime());
Your mistake is to call parse instead of format.
You call parse to parse a Date from a String, but in your case you've got a Date and need to format it using the correct Timezone.
Replace your code with
Calendar currentdate = Calendar.getInstance();
DateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
TimeZone obj = TimeZone.getTimeZone("CST");
formatter.setTimeZone(obj);
System.out.println("Local:: " +currentdate.getTime());
System.out.println("CST:: "+ formatter.format(currentdate.getTime()));
and I hope you'll get the output you are expecting.
SimpleDateFormat#setTimezone() is the answer. One formatter with ETC timezone you use for parsing, another with UTC for producing output string:
DateFormat dfNy = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.ROOT);
dfNy.setTimeZone(TimeZone.getTimeZone("EST"));
DateFormat dfUtc = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.ROOT);
dfUtc.setTimeZone(TimeZone.getTimeZone("UTC"));
try {
return dfUtc.format(dfNy.parse(input));
} catch (ParseException e) {
return null; // invalid input
}
Handling dates in Java in my daily work is a non-trivial task. I suggest you to use Joda-Time that simplify our coding days and you don't have to "re-invent the wheel".
You can use two SimpleDateFormat, one for parse the date string with EST timezone, one for print the date with UTC timezone
String format = "yyyy-MM-dd HH:mm:ss";
SimpleDateFormat estFormatter = new SimpleDateFormat(format);
estFormatter.setTimeZone(TimeZone.getTimeZone("EST"));
Date date = estFormatter.parse("2015-11-01 01:00:00");
SimpleDateFormat utcFormatter = new SimpleDateFormat(format);
utcFormatter.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println(utcFormatter.format(date));
You can just use "CST6CDT"
because in some countries they follow CDT in summer and CST in winter
public static String getDateInCST() {
Calendar calendar = Calendar.getInstance();
DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
formatter.setTimeZone(TimeZone.getTimeZone( "CST6CDT"));
String strdate = formatter.format(calendar.getTime());
TimeZone.getAvailableIDs();
return strdate;
}
Problem is when you print date obj it call toString method and it will print in your machines default time zone. Try this code and see difference.
Calendar currentdate = Calendar.getInstance();
String strdate = null;
DateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ssz");
strdate = formatter.format(currentdate.getTime());
System.out.println("strdate=>" + strdate);
TimeZone obj = TimeZone.getTimeZone("CST");
formatter.setTimeZone(obj);
strdate = formatter.format(currentdate.getTime());
Date theResult = formatter.parse(strdate);
System.out.println("The current time in India is :: " +currentdate.getTime());
System.out.println("The date and time in :: " + obj.getDisplayName() + "is ::" + theResult);
System.out.println("The date and time in :: " + obj.getDisplayName() + "is ::" + strdate);
First message, don’t handle your date and time as strings in your code. Just as you don’t handle numbers and Boolean values as strings (I hope). Use proper date-time objects.
java.time
Sometimes we get date and time as string input. It may be from a text file, from the user or from data exchange with another system, for example. In those cases parse into a proper date-time object first thing. Second message, use java.time, the modern Java date and time API, for your date and time work.
DateTimeFormatter formatter
= DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss");
String input = "2015-11-01 01:00:00";
ZonedDateTime nyTime = LocalDateTime.parse(input, formatter)
.atZone(ZoneId.of("America/New_York"));
System.out.println("Time in New York: " + nyTime);
Output from this snippet is:
Time in New York: 2015-11-01T01:00-04:00[America/New_York]
To convert to GMT:
OffsetDateTime gmtTime = nyTime.toOffsetDateTime()
.withOffsetSameInstant(ZoneOffset.UTC);
System.out.println("GMT Time: " + gmtTime);
GMT Time: 2015-11-01T05:00Z
If you need to give string output, format using a date-time formatter. Here’s an example of formatting for an American audience:
DateTimeFormatter userFormatter
= DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM)
.withLocale(Locale.US);
String formattedDateTime = gmtTime.format(userFormatter);
System.out.println("GMT Time formatted for user: " + formattedDateTime);
GMT Time formatted for user: Nov 1, 2015, 5:00:00 AM
You additionally asked:
Between the two results below, which one should you take?
I understand that you ask because both are valid answers. On November 1, 2015 summer time (DST) ended at 2 AM. That is, after 01:59:59 came 01:00:00 a second time. So when we have got 2015-11-01 01:00:00 as input, it is ambiguous. It could be in Eastern Daylight Time, equal to 05:00 GMT, or it could be in Eastern Standard Time, one hour later, hence equal to 06:00 GMT. There is no way that I can tell you which of them is correct in your case. You may control which result you get using withEarlierOffsetAtOverlap() or withLaterOffsetAtOverlap(). Above we got the DST interpretation. So to get the standard time interpretation:
nyTime = nyTime.withLaterOffsetAtOverlap();
System.out.println("Alternate time in New York: " + nyTime);
Alternate time in New York: 2015-11-01T01:00-05:00[America/New_York]
We notice that the hour of day is still 01:00, but the offset is now -05:00 instead of -04:00. This also gives us a different GMT time:
GMT Time: 2015-11-01T06:00Z
GMT Time formatted for user: Nov 1, 2015, 6:00:00 AM
Avoid SimpleDateFormat and friends
While the other answers are generally correct, the classes DateFormat, SimpleDateFormat, Date and Calendar used there are poorly designed and long outdated. The first two are particularly troublesome. I recommend you avoid all of them. I frankly find the modern API so much nicer to work with.
Link
Oracle tutorial: Date Time explaining how to use java.time.
Please refer to below mentioned code.
DateFormat utcConverter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
utcConverter.setTimeZone(TimeZone.getTimeZone("GMT"));
String sampleDateTime = "2015-11-01 01:00:00";
DateFormat nyConverter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
nyConverter.setTimeZone(TimeZone.getTimeZone("EST"));
Calendar nyCal = Calendar.getInstance();
nyCal.setTime(nyConverter.parse(sampleDateTime));
System.out.println("NY TIME :" +nyConverter.format(nyCal.getTime()));
System.out.println("GMT TIME :" +utcConverter.format(nyCal.getTime()));
2020 Answer Here
If you want the new java.time.* feature but still want to mess with java.util.Date:
public static Date convertBetweenTwoTimeZone(Date date, String fromTimeZone, String toTimeZone) {
ZoneId fromTimeZoneId = ZoneId.of(fromTimeZone);
ZoneId toTimeZoneId = ZoneId.of(toTimeZone);
ZonedDateTime fromZonedDateTime =
ZonedDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault()).withZoneSameLocal(fromTimeZoneId);
ZonedDateTime toZonedDateTime = fromZonedDateTime
.withZoneSameInstant(toTimeZoneId)
.withZoneSameLocal(ZoneId.systemDefault())
;
return Date.from(toZonedDateTime.toInstant());
}
for java.sql.Timestamp
public static Timestamp convertBetweenTwoTimeZone(Timestamp timestamp, String fromTimeZone, String toTimeZone) {
ZoneId fromTimeZoneId = ZoneId.of(fromTimeZone);
ZoneId toTimeZoneId = ZoneId.of(toTimeZone);
LocalDateTime localDateTimeBeforeDST = timestamp.toLocalDateTime();
ZonedDateTime fromZonedDateTime = ZonedDateTime.of(localDateTimeBeforeDST, fromTimeZoneId);
ZonedDateTime toZonedDateTime = fromZonedDateTime.withZoneSameInstant(toTimeZoneId);
return Timestamp.valueOf(toZonedDateTime.toLocalDateTime());
}
For google calendar API
private String getFormatedDate(Date date)
{
DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss+05:30");
df.setTimeZone(TimeZone.getTimeZone("GMT+05:30"));
return df.format(date);
}
And how to print it as a string.
I tried this but I get the date in (YYYMMMMDDD HHSSMM) format:
System.out.println(LocalDateTime.now());
What is the easiest way to get the current date in (YYYYMMDD) format?
is that what you are looking for?
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd");
System.out.println(LocalDate.now().format(formatter));
This does the trick but may not be the easiest:
import java.util.*;
import java.text.*;
class Test {
public static void main (String[] args) {
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd");
Date date = new Date();
System.out.println(dateFormat.format(date));
}
}
DateTimeFormatter.BASIC_ISO_DATE.format(LocalDate.now());
This is a very old question but gets me every time. There is a much simpler way now in one line:
String now = Instant.now().atZone(ZoneOffset.UTC).format(DateTimeFormatter.ISO_LOCAL_DATE);
System.out.println(now);
outputs: 2020-07-09
Just use: SimpleDateFormat
// Create an instance of SimpleDateFormat used for formatting
// the string representation of date (month/day/year)
DateFormat df = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
// Get the date today using Calendar object.
Date today = Calendar.getInstance().getTime();
// Using DateFormat format method we can create a string
// representation of a date with the defined format.
String reportDate = df.format(today);
// Print what date is today!
System.out.println("Report Date: " + reportDate);
http://www.mkyong.com/java/how-to-convert-string-to-date-java/
i have written this code to convert the current system date and time to some other timezone. I am not getting any error but i am not getting my output as expected. Like if i execute my program at a particular time.. My output is ::
The current time in India is :: Fri Feb 24 16:09:23 IST 2012
The date and time in :: Central Standard Time is :: Sat Feb 25 03:39:23 IST 2012
And the actual Time according to CST time zone is ::
Friday, 24 February 4:39:16 a.m(GMT - 6:00)
So there's some time gap. and i don't know why this is happening. Any help will be appreciated.. The code is ::
package MyPackage;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
public class Temp2 {
public static void main(String[] args) {
try {
Calendar currentdate = Calendar.getInstance();
String strdate = null;
DateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
strdate = formatter.format(currentdate.getTime());
TimeZone obj = TimeZone.getTimeZone("CST");
formatter.setTimeZone(obj);
//System.out.println(strdate);
//System.out.println(formatter.parse(strdate));
Date theResult = formatter.parse(strdate);
System.out.println("The current time in India is :: " +currentdate.getTime());
System.out.println("The date and time in :: "+ obj.getDisplayName() + "is ::" + theResult);
} catch (ParseException e) {
e.printStackTrace();
}
}
}
It's over the web. Could have googled. Anyways, here is a version for you (shamelessly picked and modified from here):
Calendar calendar = Calendar.getInstance();
TimeZone fromTimeZone = calendar.getTimeZone();
TimeZone toTimeZone = TimeZone.getTimeZone("CST");
calendar.setTimeZone(fromTimeZone);
calendar.add(Calendar.MILLISECOND, fromTimeZone.getRawOffset() * -1);
if (fromTimeZone.inDaylightTime(calendar.getTime())) {
calendar.add(Calendar.MILLISECOND, calendar.getTimeZone().getDSTSavings() * -1);
}
calendar.add(Calendar.MILLISECOND, toTimeZone.getRawOffset());
if (toTimeZone.inDaylightTime(calendar.getTime())) {
calendar.add(Calendar.MILLISECOND, toTimeZone.getDSTSavings());
}
System.out.println(calendar.getTime());
Your mistake is to call parse instead of format.
You call parse to parse a Date from a String, but in your case you've got a Date and need to format it using the correct Timezone.
Replace your code with
Calendar currentdate = Calendar.getInstance();
DateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
TimeZone obj = TimeZone.getTimeZone("CST");
formatter.setTimeZone(obj);
System.out.println("Local:: " +currentdate.getTime());
System.out.println("CST:: "+ formatter.format(currentdate.getTime()));
and I hope you'll get the output you are expecting.
SimpleDateFormat#setTimezone() is the answer. One formatter with ETC timezone you use for parsing, another with UTC for producing output string:
DateFormat dfNy = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.ROOT);
dfNy.setTimeZone(TimeZone.getTimeZone("EST"));
DateFormat dfUtc = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.ROOT);
dfUtc.setTimeZone(TimeZone.getTimeZone("UTC"));
try {
return dfUtc.format(dfNy.parse(input));
} catch (ParseException e) {
return null; // invalid input
}
Handling dates in Java in my daily work is a non-trivial task. I suggest you to use Joda-Time that simplify our coding days and you don't have to "re-invent the wheel".
You can use two SimpleDateFormat, one for parse the date string with EST timezone, one for print the date with UTC timezone
String format = "yyyy-MM-dd HH:mm:ss";
SimpleDateFormat estFormatter = new SimpleDateFormat(format);
estFormatter.setTimeZone(TimeZone.getTimeZone("EST"));
Date date = estFormatter.parse("2015-11-01 01:00:00");
SimpleDateFormat utcFormatter = new SimpleDateFormat(format);
utcFormatter.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println(utcFormatter.format(date));
You can just use "CST6CDT"
because in some countries they follow CDT in summer and CST in winter
public static String getDateInCST() {
Calendar calendar = Calendar.getInstance();
DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
formatter.setTimeZone(TimeZone.getTimeZone( "CST6CDT"));
String strdate = formatter.format(calendar.getTime());
TimeZone.getAvailableIDs();
return strdate;
}
Problem is when you print date obj it call toString method and it will print in your machines default time zone. Try this code and see difference.
Calendar currentdate = Calendar.getInstance();
String strdate = null;
DateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ssz");
strdate = formatter.format(currentdate.getTime());
System.out.println("strdate=>" + strdate);
TimeZone obj = TimeZone.getTimeZone("CST");
formatter.setTimeZone(obj);
strdate = formatter.format(currentdate.getTime());
Date theResult = formatter.parse(strdate);
System.out.println("The current time in India is :: " +currentdate.getTime());
System.out.println("The date and time in :: " + obj.getDisplayName() + "is ::" + theResult);
System.out.println("The date and time in :: " + obj.getDisplayName() + "is ::" + strdate);
First message, don’t handle your date and time as strings in your code. Just as you don’t handle numbers and Boolean values as strings (I hope). Use proper date-time objects.
java.time
Sometimes we get date and time as string input. It may be from a text file, from the user or from data exchange with another system, for example. In those cases parse into a proper date-time object first thing. Second message, use java.time, the modern Java date and time API, for your date and time work.
DateTimeFormatter formatter
= DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss");
String input = "2015-11-01 01:00:00";
ZonedDateTime nyTime = LocalDateTime.parse(input, formatter)
.atZone(ZoneId.of("America/New_York"));
System.out.println("Time in New York: " + nyTime);
Output from this snippet is:
Time in New York: 2015-11-01T01:00-04:00[America/New_York]
To convert to GMT:
OffsetDateTime gmtTime = nyTime.toOffsetDateTime()
.withOffsetSameInstant(ZoneOffset.UTC);
System.out.println("GMT Time: " + gmtTime);
GMT Time: 2015-11-01T05:00Z
If you need to give string output, format using a date-time formatter. Here’s an example of formatting for an American audience:
DateTimeFormatter userFormatter
= DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM)
.withLocale(Locale.US);
String formattedDateTime = gmtTime.format(userFormatter);
System.out.println("GMT Time formatted for user: " + formattedDateTime);
GMT Time formatted for user: Nov 1, 2015, 5:00:00 AM
You additionally asked:
Between the two results below, which one should you take?
I understand that you ask because both are valid answers. On November 1, 2015 summer time (DST) ended at 2 AM. That is, after 01:59:59 came 01:00:00 a second time. So when we have got 2015-11-01 01:00:00 as input, it is ambiguous. It could be in Eastern Daylight Time, equal to 05:00 GMT, or it could be in Eastern Standard Time, one hour later, hence equal to 06:00 GMT. There is no way that I can tell you which of them is correct in your case. You may control which result you get using withEarlierOffsetAtOverlap() or withLaterOffsetAtOverlap(). Above we got the DST interpretation. So to get the standard time interpretation:
nyTime = nyTime.withLaterOffsetAtOverlap();
System.out.println("Alternate time in New York: " + nyTime);
Alternate time in New York: 2015-11-01T01:00-05:00[America/New_York]
We notice that the hour of day is still 01:00, but the offset is now -05:00 instead of -04:00. This also gives us a different GMT time:
GMT Time: 2015-11-01T06:00Z
GMT Time formatted for user: Nov 1, 2015, 6:00:00 AM
Avoid SimpleDateFormat and friends
While the other answers are generally correct, the classes DateFormat, SimpleDateFormat, Date and Calendar used there are poorly designed and long outdated. The first two are particularly troublesome. I recommend you avoid all of them. I frankly find the modern API so much nicer to work with.
Link
Oracle tutorial: Date Time explaining how to use java.time.
Please refer to below mentioned code.
DateFormat utcConverter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
utcConverter.setTimeZone(TimeZone.getTimeZone("GMT"));
String sampleDateTime = "2015-11-01 01:00:00";
DateFormat nyConverter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
nyConverter.setTimeZone(TimeZone.getTimeZone("EST"));
Calendar nyCal = Calendar.getInstance();
nyCal.setTime(nyConverter.parse(sampleDateTime));
System.out.println("NY TIME :" +nyConverter.format(nyCal.getTime()));
System.out.println("GMT TIME :" +utcConverter.format(nyCal.getTime()));
2020 Answer Here
If you want the new java.time.* feature but still want to mess with java.util.Date:
public static Date convertBetweenTwoTimeZone(Date date, String fromTimeZone, String toTimeZone) {
ZoneId fromTimeZoneId = ZoneId.of(fromTimeZone);
ZoneId toTimeZoneId = ZoneId.of(toTimeZone);
ZonedDateTime fromZonedDateTime =
ZonedDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault()).withZoneSameLocal(fromTimeZoneId);
ZonedDateTime toZonedDateTime = fromZonedDateTime
.withZoneSameInstant(toTimeZoneId)
.withZoneSameLocal(ZoneId.systemDefault())
;
return Date.from(toZonedDateTime.toInstant());
}
for java.sql.Timestamp
public static Timestamp convertBetweenTwoTimeZone(Timestamp timestamp, String fromTimeZone, String toTimeZone) {
ZoneId fromTimeZoneId = ZoneId.of(fromTimeZone);
ZoneId toTimeZoneId = ZoneId.of(toTimeZone);
LocalDateTime localDateTimeBeforeDST = timestamp.toLocalDateTime();
ZonedDateTime fromZonedDateTime = ZonedDateTime.of(localDateTimeBeforeDST, fromTimeZoneId);
ZonedDateTime toZonedDateTime = fromZonedDateTime.withZoneSameInstant(toTimeZoneId);
return Timestamp.valueOf(toZonedDateTime.toLocalDateTime());
}
For google calendar API
private String getFormatedDate(Date date)
{
DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss+05:30");
df.setTimeZone(TimeZone.getTimeZone("GMT+05:30"));
return df.format(date);
}
I have written a small program in which a user enters minutes and program shows the current Date and Time + minutes entered by the user.
final String DATE_FORMAT_NOW = "MM/dd/yyyy HH:mm:ss";
final DateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss", Locale.US);
Calendar cal = Calendar.getInstance();
cal.add(Calendar.MINUTE, Integer.valueOf(sample.getMinutes()));
SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
String dt = sdf.format(cal.getTime());
System.out.println(" Date and time with added Minutes : " + (dateFormat.parse(dt));
Sample
private String minutes;
//getter and setter
I am getting this exception
java.lang.NumberFormatException: For input string: ""
What I am doing wrong here?
Should I use
Integer.parseInt
or
Integer.valueOf(Integer.parseInt(sample.getMinutes())));?
With current date and time.
public static void main(String[] args)
{
try
{
final String DATE_FORMAT_NOW = "MM/dd/yyyy HH:mm:ss";
final DateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss", Locale.US);
Date sample = new Date();
int iMinutes = 30;//minutes added by the user
Calendar cal = Calendar.getInstance();
cal.add(Calendar.MINUTE, Integer.valueOf(sample.getMinutes()));
SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
String dt = sdf.format(cal.getTime());
System.out.println("Current Date and time:"+sample);
System.out.println("Date and time with added Minutes : " + (dateFormat.parse(dt)));
}
catch (ParseException ex)
{
Logger.getLogger(NewMain.class.getName()).log(Level.SEVERE, null, ex);
}
}
The output will be displays as:
Current Date and time:Tue Jun 12 15:57:55 IST 2012
Date and time with added Minutes : Tue Jun 12 16:54:55 IST 2012
Here the minutes "57" was added to the calendar and the time has moved forward by "30" mins.And that is the your result(Date and time with added Minutes).
With user in input minutes.
public static void main(String[] args)
{
try
{
final String DATE_FORMAT_NOW = "MM/dd/yyyy HH:mm:ss";
final DateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss", Locale.US);
int iMinutes = 30;//minutes added by the user
Calendar cal = Calendar.getInstance();
cal.add(Calendar.MINUTE, iMinutes);
SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
String dt = sdf.format(cal.getTime());
System.out.println("Current Date and time:"+sample);
System.out.println("Date and time with added Minutes : " + (dateFormat.parse(dt)));
}
catch (ParseException ex)
{
Logger.getLogger(NewMain.class.getName()).log(Level.SEVERE, null, ex);
}
}
This will work as per your desire first you take the minutes from the user and assign that minutes to the "iMinutes" variable of the code it will add that much minutes to the calander.
The output will be displayed as:
Current Date and time:Tue Jun 12 16:07:55 IST 2012
Date and time with added Minutes : Tue Jun 12 16:37:55 IST 2012
And if you want to set the minutes then use "set" instead of "add" in the "cal.add".
Hope this will solve your problem.
Regards.
Check if the returned string from sample.getMinutes() is a number or not. It must be a number without any white space to be parsed, otherwise you will get a NumberFormatException.
The problem you're having is that an empty string is not a valid integer. Your application should catch the exception, and set a sensible default instead.
"" is an empty string and it cannot be parsed into a valid integer given any circumstances
java.lang.NumberFormatException: For input string: ""
An empty String cannot be parsed to a number.
You need to check it first (using something like String#length() or StringUtils#isBlank()) and decide what to do with this case (for example treat it as zero).
java.lang.NumberFormatException: For input string: ""
Seems like you never set the minutes String
java.lang.NumberFormatException: For input string: ""
input String "" can not be converted into valid Integer.
before using Integer.parseInt, you ensure you are getting an integer by the following ways.
1.provide javascript validation for checking int
or/and
2.provide a server side validation for checking non-integer Strings
also see how to avoid NumberFormatException
Add some sort of checking:
final String DATE_FORMAT_NOW = "MM/dd/yyyy HH:mm:ss";
final DateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss", Locale.US);
Calendar cal = Calendar.getInstance();
final String minutes = sample.getMinutes()
cal.add(Calendar.MINUTE, Integer.valueOf((minutes != null && !minutes.isEmpty()) ? minutes : 0);
SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
String dt = sdf.format(cal.getTime());
System.out.println(" Date and time with added Minutes : " + (dateFormat.parse(dt));
There is nothing unusal here. Read the java docs for parseInt() and valueOf which clearly states that a NumberFormatException is thrown if the String does not contain a parsable integer. And an empty string "" is not a parsable int.
It is up to you how you handle such cases for which a NumberFormatException is thrown.