Convert hour interval to 24h interval - java

I would like to convert "9:00 am – 11:00 pm" -> "9:00 - 23:00", how can I do that? What I've tried so far:
if(input.contains("am")) { //This because I have a string with other kind of items too (not only these interval of hours but names, etc)
DateFormat df = new SimpleDateFormat("h:mm a – h:mm a");
DateFormat outputformat = new SimpleDateFormat("HH:mm - HH:mm");
Date date = null;
String output = null;
date= df.parse(input);
input = outputformat.format(date);
System.out.println("Output: "+output);
}
but the output is wrong, in the example 23:00 - 23:00 because it doesn't recognize the first and the second hour
I tried also something like:
DateFormat df = new SimpleDateFormat("h:mm a" +" - "+ "h:mm a");
DateFormat outputformat = new SimpleDateFormat("HH:mm"+" - "+ "HH:mm");
but I got a parse error then


Try this:
String dateToParse = "9:00 am – 11:00 pm";
String splitDate[] = dateToParse.split("–");
DateFormat df = new SimpleDateFormat("h:mm a");
DateFormat outputformat = new SimpleDateFormat("HH:mm");
Date date1 = null, date2 = null;
String output1 = null, output2 = null;
try {
date1 = df.parse(splitDate[0].trim());
date2 = df.parse(splitDate[1].trim());
} catch (ParseException e) {
e.printStackTrace();
}
output1 = outputformat.format(date1);
output2 = outputformat.format(date2);
System.out.println("Output: " + output1 + " – " + output2);


Go object-oriented and use java.time
Don’t convert your interval from one string format to another. Design an Interval class for storing and manipulating your time intervals. I suggest that you include a convenience constructor that accepts a string and a toString method that produces your desired format.
I furthermore recommend that you use java.time, the modern Java date and time API, for your time work.
public class Interval {
private static final String middlePart = " – ";
private static final DateTimeFormatter amPmFormatter = new DateTimeFormatterBuilder()
.parseCaseInsensitive()
.appendPattern("h:mm a")
.toFormatter(Locale.ENGLISH);
private LocalTime begin;
private LocalTime end;
public Interval(String intervalString) {
String[] timeStrings = intervalString.split(middlePart);
if (timeStrings.length != 2) {
throw new IllegalArgumentException("Improper format");
}
begin = LocalTime.parse(timeStrings[0], amPmFormatter);
end = LocalTime.parse(timeStrings[1], amPmFormatter);
}
#Override
public String toString() {
return "" + begin + middlePart + end;
}
}
To try it out:
Interval testInterval = new Interval("9:00 am – 11:00 pm");
System.out.println(testInterval);
Output is:
09:00 – 23:00
What went wrong in your code?
Date is the completely wrong class to use for your interval. The class is poorly designed and long outdated. A date represents a point in time, not a time of day and certainly not an interval of two times of day.
SimpleDateFormat — a notorious troublemaker of a class — tried to parse your string into a time of January 1, 1970 in your time zone. It should have objected because a time on that day cannot be both 9 AM and 11 PM — you were contradicting yourself. But no, SimpleDateFormat gives you one of those times, keeps its mouth shut and pretends all is well. Possibly an attempt to be nice, but if so, IMHO a completely misunderstood attempt.
Link
Oracle tutorial: Date Time explaining how to use java.time.

Related

How can I get a date to be put into input? Then how can I get it to make a due date based on an undetermined rental period inputed by the user? [duplicate]

I've a String representing a date.
String date_s = "2011-01-18 00:00:00.0";
I'd like to convert it to a Date and output it in YYYY-MM-DD format.
2011-01-18
How can I achieve this?
Okay, based on the answers I retrieved below, here's something I've tried:
String date_s = " 2011-01-18 00:00:00.0";
SimpleDateFormat dt = new SimpleDateFormat("yyyyy-mm-dd hh:mm:ss");
Date date = dt.parse(date_s);
SimpleDateFormat dt1 = new SimpleDateFormat("yyyyy-mm-dd");
System.out.println(dt1.format(date));
But it outputs 02011-00-1 instead of the desired 2011-01-18. What am I doing wrong?

Use LocalDateTime#parse() (or ZonedDateTime#parse() if the string happens to contain a time zone part) to parse a String in a certain pattern into a LocalDateTime.
String oldstring = "2011-01-18 00:00:00.0";
LocalDateTime datetime = LocalDateTime.parse(oldstring, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.S"));
Then use LocalDateTime#format() (or ZonedDateTime#format()) to format a LocalDateTime into a String in a certain pattern.
String newstring = datetime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd"));
System.out.println(newstring); // 2011-01-18
Or, when you're not on Java 8 yet, use SimpleDateFormat#parse() to parse a String in a certain pattern into a Date.
String oldstring = "2011-01-18 00:00:00.0";
Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S").parse(oldstring);
Then use SimpleDateFormat#format() to format a Date into a String in a certain pattern.
String newstring = new SimpleDateFormat("yyyy-MM-dd").format(date);
System.out.println(newstring); // 2011-01-18
See also:
Java string to date conversion
Update: as per your failed attempt which you added to the question after this answer was posted; the patterns are case sensitive. Carefully read the java.text.SimpleDateFormat javadoc what the individual parts stands for. So stands for example M for months and m for minutes. Also, years exist of four digits yyyy, not five yyyyy. Look closer at the code snippets I posted here above.

Formatting are CASE-SENSITIVE so USE MM for month not mm (this is for minute) and yyyy
For Reference you can use following cheatsheet.
G Era designator Text AD
y Year Year 1996; 96
Y Week year Year 2009; 09
M Month in year Month July; Jul; 07
w Week in year Number 27
W Week in month Number 2
D Day in year Number 189
d Day in month Number 10
F Day of week in month Number 2
E Day name in week Text Tuesday; Tue
u Day number of week (1 = Monday, ..., 7 = Sunday) Number 1
a Am/pm marker Text PM
H Hour in day (0-23) Number 0
k Hour in day (1-24) Number 24
K Hour in am/pm (0-11) Number 0
h Hour in am/pm (1-12) Number 12
m Minute in hour Number 30
s Second in minute Number 55
S Millisecond Number 978
z Time zone General time zone Pacific Standard Time; PST; GMT-08:00
Z Time zone RFC 822 time zone -0800
X Time zone ISO 8601 time zone -08; -0800; -08:00
Examples:
"yyyy.MM.dd G 'at' HH:mm:ss z" 2001.07.04 AD at 12:08:56 PDT
"EEE, MMM d, ''yy" Wed, Jul 4, '01
"h:mm a" 12:08 PM
"hh 'o''clock' a, zzzz" 12 o'clock PM, Pacific Daylight Time
"K:mm a, z" 0:08 PM, PDT
"yyyyy.MMMMM.dd GGG hh:mm aaa" 02001.July.04 AD 12:08 PM
"EEE, d MMM yyyy HH:mm:ss Z" Wed, 4 Jul 2001 12:08:56 -0700
"yyMMddHHmmssZ" 010704120856-0700
"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'" 2001-07-04T12:08:56.235-0700
"yyyy-MM-dd'T'HH:mm:ss.SSSXXX" 2001-07-04T12:08:56.235-07:00
"YYYY-'W'ww-u" 2001-W27-3

The answer is of course to create a SimpleDateFormat object and use it to parse Strings to Date and to format Dates to Strings. If you've tried SimpleDateFormat and it didn't work, then please show your code and any errors you may receive.
Addendum: "mm" in the format String is not the same as "MM". Use MM for months and mm for minutes. Also, yyyyy is not the same as yyyy. e.g.,:
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class FormateDate {
public static void main(String[] args) throws ParseException {
String date_s = "2011-01-18 00:00:00.0";
// *** note that it's "yyyy-MM-dd hh:mm:ss" not "yyyy-mm-dd hh:mm:ss"
SimpleDateFormat dt = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
Date date = dt.parse(date_s);
// *** same for the format String below
SimpleDateFormat dt1 = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(dt1.format(date));
}
}

Why not simply use this
Date convertToDate(String receivedDate) throws ParseException{
SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy");
Date date = formatter.parse(receivedDate);
return date;
}
Also, this is the other way :
DateFormat df = new SimpleDateFormat("dd/MM/yyyy");
String requiredDate = df.format(new Date()).toString();
or
Date requiredDate = df.format(new Date());

Using the java.time package in Java 8 and later:
String date = "2011-01-18 00:00:00.0";
TemporalAccessor temporal = DateTimeFormatter
.ofPattern("yyyy-MM-dd HH:mm:ss.S")
.parse(date); // use parse(date, LocalDateTime::from) to get LocalDateTime
String output = DateTimeFormatter.ofPattern("yyyy-MM-dd").format(temporal);

[edited to include BalusC's corrections]
The SimpleDateFormat class should do the trick:
String pattern = "yyyy-MM-dd HH:mm:ss.S";
SimpleDateFormat format = new SimpleDateFormat(pattern);
try {
Date date = format.parse("2011-01-18 00:00:00.0");
System.out.println(date);
} catch (ParseException e) {
e.printStackTrace();
}

Please refer "Date and Time Patterns" here. http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html
import java.text.SimpleDateFormat;
import java.util.Date;
import java.text.ParseException;
public class DateConversionExample{
public static void main(String arg[]){
try{
SimpleDateFormat sourceDateFormat = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");
Date date = sourceDateFormat.parse("2011-01-18 00:00:00.0");
SimpleDateFormat targetDateFormat = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(targetDateFormat.format(date));
}catch(ParseException e){
e.printStackTrace();
}
}
}

Other answers are correct, basically you had the wrong number of "y" characters in your pattern.
Time Zone
One more problem though… You did not address time zones. If you intended UTC, then you should have said so. If not, the answers are not complete. If all you want is the date portion without the time, then no issue. But if you do further work that may involve time, then you should be specifying a time zone.
Joda-Time
Here is the same kind of code but using the third-party open-source Joda-Time 2.3 library
// © 2013 Basil Bourque. This source code may be used freely forever by anyone taking full responsibility for doing so.
String date_s = "2011-01-18 00:00:00.0";
org.joda.time.format.DateTimeFormatter formatter = org.joda.time.format.DateTimeFormat.forPattern( "yyyy-MM-dd' 'HH:mm:ss.SSS" );
// By the way, if your date-time string conformed strictly to ISO 8601 including a 'T' rather than a SPACE ' ', you could
// use a formatter built into Joda-Time rather than specify your own: ISODateTimeFormat.dateHourMinuteSecondFraction().
// Like this:
//org.joda.time.DateTime dateTimeInUTC = org.joda.time.format.ISODateTimeFormat.dateHourMinuteSecondFraction().withZoneUTC().parseDateTime( date_s );
// Assuming the date-time string was meant to be in UTC (no time zone offset).
org.joda.time.DateTime dateTimeInUTC = formatter.withZoneUTC().parseDateTime( date_s );
System.out.println( "dateTimeInUTC: " + dateTimeInUTC );
System.out.println( "dateTimeInUTC (date only): " + org.joda.time.format.ISODateTimeFormat.date().print( dateTimeInUTC ) );
System.out.println( "" ); // blank line.
// Assuming the date-time string was meant to be in Kolkata time zone (formerly known as Calcutta). Offset is +5:30 from UTC (note the half-hour).
org.joda.time.DateTimeZone kolkataTimeZone = org.joda.time.DateTimeZone.forID( "Asia/Kolkata" );
org.joda.time.DateTime dateTimeInKolkata = formatter.withZone( kolkataTimeZone ).parseDateTime( date_s );
System.out.println( "dateTimeInKolkata: " + dateTimeInKolkata );
System.out.println( "dateTimeInKolkata (date only): " + org.joda.time.format.ISODateTimeFormat.date().print( dateTimeInKolkata ) );
// This date-time in Kolkata is a different point in the time line of the Universe than the dateTimeInUTC instance created above. The date is even different.
System.out.println( "dateTimeInKolkata adjusted to UTC: " + dateTimeInKolkata.toDateTime( org.joda.time.DateTimeZone.UTC ) );
When run…
dateTimeInUTC: 2011-01-18T00:00:00.000Z
dateTimeInUTC (date only): 2011-01-18
dateTimeInKolkata: 2011-01-18T00:00:00.000+05:30
dateTimeInKolkata (date only): 2011-01-18
dateTimeInKolkata adjusted to UTC: 2011-01-17T18:30:00.000Z

try
{
String date_s = "2011-01-18 00:00:00.0";
SimpleDateFormat simpledateformat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S");
Date tempDate=simpledateformat.parse(date_s);
SimpleDateFormat outputDateFormat = new SimpleDateFormat("yyyy-MM-dd");
System.out.println("Output date is = "+outputDateFormat.format(tempDate));
} catch (ParseException ex)
{
System.out.println("Parse Exception");
}

You can just use:
Date yourDate = new Date();
SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd");
String date = DATE_FORMAT.format(yourDate);
It works perfectly!

public class SystemDateTest {
String stringDate;
public static void main(String[] args) {
SystemDateTest systemDateTest = new SystemDateTest();
// format date into String
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MM-yyyy hh:mm:ss");
systemDateTest.setStringDate(simpleDateFormat.format(systemDateTest.getDate()));
System.out.println(systemDateTest.getStringDate());
}
public Date getDate() {
return new Date();
}
public String getStringDate() {
return stringDate;
}
public void setStringDate(String stringDate) {
this.stringDate = stringDate;
}
}

String str = "2000-12-12";
Date dt = null;
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
try
{
dt = formatter.parse(str);
}
catch (Exception e)
{
}
JOptionPane.showMessageDialog(null, formatter.format(dt));

You could try Java 8 new date, more information can be found on the Oracle documentation.
Or you can try the old one
public static Date getDateFromString(String format, String dateStr) {
DateFormat formatter = new SimpleDateFormat(format);
Date date = null;
try {
date = (Date) formatter.parse(dateStr);
} catch (ParseException e) {
e.printStackTrace();
}
return date;
}
public static String getDate(Date date, String dateFormat) {
DateFormat formatter = new SimpleDateFormat(dateFormat);
return formatter.format(date);
}

You can also use substring()
String date_s = "2011-01-18 00:00:00.0";
date_s.substring(0,10);
If you want a space in front of the date, use
String date_s = " 2011-01-18 00:00:00.0";
date_s.substring(1,11);

private SimpleDateFormat dataFormat = new SimpleDateFormat("dd/MM/yyyy");
#Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
if(value instanceof Date) {
value = dataFormat.format(value);
}
return super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
};

remove one y form the format provide to:
SimpleDateFormat dt1 = new SimpleDateFormat("yyyyy-mm-dd");
It should be:
SimpleDateFormat dt1 = new SimpleDateFormat("yyyy-mm-dd");

We can convert Today's date in the format of 'JUN 12, 2020'.
String.valueOf(DateFormat.getDateInstance().format(new Date())));

/**
* Method will take Date in "MMMM, dd yyyy HH:mm:s" format and return time difference like added: 3 min ago
*
* #param date : date in "MMMM, dd yyyy HH:mm:s" format
* #return : time difference
*/
private String getDurationTimeStamp(String date) {
String timeDifference = "";
//date formatter as per the coder need
SimpleDateFormat sdf = new SimpleDateFormat("MMMM, dd yyyy HH:mm:s");
TimeZone timeZone = TimeZone.getTimeZone("EST");
sdf.setTimeZone(timeZone);
Date startDate = null;
try {
startDate = sdf.parse(date);
} catch (ParseException e) {
MyLog.printStack(e);
}
//end date will be the current system time to calculate the lapse time difference
Date endDate = new Date();
//get the time difference in milliseconds
long duration = endDate.getTime() - startDate.getTime();
long diffInSeconds = TimeUnit.MILLISECONDS.toSeconds(duration);
long diffInMinutes = TimeUnit.MILLISECONDS.toMinutes(duration);
long diffInHours = TimeUnit.MILLISECONDS.toHours(duration);
long diffInDays = TimeUnit.MILLISECONDS.toDays(duration);
if (diffInDays >= 365) {
int year = (int) (diffInDays / 365);
timeDifference = year + mContext.getString(R.string.year_ago);
} else if (diffInDays >= 30) {
int month = (int) (diffInDays / 30);
timeDifference = month + mContext.getString(R.string.month_ago);
}
//if days are not enough to create year then get the days
else if (diffInDays >= 1) {
timeDifference = diffInDays + mContext.getString(R.string.day_ago);
}
//if days value<1 then get the hours
else if (diffInHours >= 1) {
timeDifference = diffInHours + mContext.getString(R.string.hour_ago);
}
//if hours value<1 then get the minutes
else if (diffInMinutes >= 1) {
timeDifference = diffInMinutes + mContext.getString(R.string.min_ago);
}
//if minutes value<1 then get the seconds
else if (diffInSeconds >= 1) {
timeDifference = diffInSeconds + mContext.getString(R.string.sec_ago);
} else if (timeDifference.isEmpty()) {
timeDifference = mContext.getString(R.string.now);
}
return mContext.getString(R.string.added) + " " + timeDifference;
}

Say you want to change 2019-12-20 10:50 AM GMT+6:00 to 2019-12-20 10:50 AM
first of all you have to understand the date format first one date format is
yyyy-MM-dd hh:mm a zzz and second one date format will be yyyy-MM-dd hh:mm a
just return a string from this function like.
public String convertToOnlyDate(String currentDate) {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm a ");
Date date;
String dateString = "";
try {
date = dateFormat.parse(currentDate);
System.out.println(date.toString());
dateString = dateFormat.format(date);
} catch (ParseException e) {
e.printStackTrace();
}
return dateString;
}
This function will return your desire answer. If you want to customize more just add or remove component from the date format.

you have some wrong:
SimpleDateFormat dt1 = new SimpleDateFormat("yyyyy-mm-dd");
first :
should be
new SimpleDateFormat("yyyy-mm-dd");
//yyyy 4 not 5
this display 02011, but yyyy it disply 2011
second:
change your code like this
new SimpleDateFormat("yyyy-MM-dd");
i hope help you

java.time
In March 2014, modern date-time API* API supplanted the error-prone java.util date-time API and their formatting API, SimpleDateFormat. Since then it has been highly recommended to stop using the legacy API.
Also, quoted below is a notice from the home page of Joda-Time:
Note that from Java SE 8 onwards, users are asked to migrate to java.time (JSR-310) - a core part of the JDK which replaces this project.
You do not need DateTimeFormatter for formatting
You need DateTimeFormatter only for parsing your string but you do not need a DateTimeFormatter to get the date in the desired format. The modern Date-Time API is based on ISO 8601 and thus the toString implementation of java.time types return a string in ISO 8601 format. Your desired format is the default format of LocalDate#toString.
Solution using java.time, the modern Date-Time API:
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
public class Main {
public static void main(String[] args) {
String strDate = "2011-01-18 00:00:00.0";
DateTimeFormatter dtfInput = DateTimeFormatter.ofPattern("u-M-d H:m:s.S", Locale.ENGLISH);
LocalDateTime ldt = LocalDateTime.parse(strDate, dtfInput);
// Alternatively,
// LocalDateTime ldt = dtfInput.parse(strDate, LocalDateTime::from);
LocalDate date = ldt.toLocalDate();
System.out.println(date);
}
}
Output:
2011-01-18
ONLINE DEMO
Some important notes about the solution:
java.time made it possible to call parse and format functions on the Date-Time type itself, in addition to the traditional way (i.e. calling parse and format functions on the formatter type, which is DateTimeFormatter in case of java.time API).
Here, you can use y instead of u but I prefer u to y.
Learn more about the modern Date-Time API from Trail: Date Time.
* For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and How to use ThreeTenABP in Android Project.

SimpleDateFormat dt1 = new SimpleDateFormat("yyyy-mm-dd");

Java SimpleDateformatter with 10 decimals after the seconds, cannot convert to Date

I'm trying to convert date string with 10 milliseconds (2018-11-02 6:05:59.1541162159 PM) to date but not able get the exact date.
Code to convert:
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
public class DateFormatCheck {
private static TimeZone tz = TimeZone.getTimeZone("Asia/Colombo");
private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS aa");
public static void main(String[] a){
try {
Calendar cal = Calendar.getInstance(tz);
sdf.setCalendar(cal);
cal.setTime(sdf.parse("2018-11-02 6:05:59.1541162159 PM"));
Date date = cal.getTime();
System.out.println(date);
}catch (Exception e){
e.printStackTrace();
}
}
}
Output:
Tue Nov 20 02:12:01 IST 2018

There are multiple problems at the moment. I'd strongly recommend using java.time for as much work as possible, although even that doesn't make this easy.
As you say, your value has 10 digits for "fraction of a second" - which means it goes down to 10th-of-a-nanosecond precision. That's highly unusual to start with, in my experience - and I don't think Java can handle that, even with java.time.
I suspect you'll need to massage the data first, down to 9 digits of precision. At that point, it's fairly straightforward to parse the value to a ZonedDateTime:
// Note this only has 9 digits of precision, not the original 10
String text = "2018-11-02 6:05:59.154116215 PM";
ZoneId zone = ZoneId.of("Asia/Colombo");
DateTimeFormatter formatter = DateTimeFormatter.ofPattern(
"yyyy-MM-dd h:mm:ss.SSSSSSSSS a", Locale.US)
.withZone(zone);
ZonedDateTime parsed = ZonedDateTime.parse(text, formatter);
System.out.println(parsed);
Note how I've provided SSSSSSSSS as the fraction-of-a-second part, to handle all 9 digits. Also note the use of h instead of HH - HH would mean "24-hour hour of day, with 0 padding" - neither part of which is true for your original value, which uses "6" for 6pm. It's very rare that you would want to combine H or HH with a.
That code gives you a ZonedDateTime, which you could convert into a Date like this:
Date date = Date.from(parsed.toInstant());
I'd recommend you don't do that unless you really, really need to for interop reasons though; the Date API is nasty in various ways.

You need to format the date first with your SimpleDateFormat object:
System.out.println(sdf.format(date));
Edit: Do this once the parsing issue is resolved to print it out correctly.

String dateText = "2018-11-02 6:05:59.1541162159 PM";
String[] parsedText = dateText.split("\\.");
String[] parsedText2 = parsedText[1].split(" ");
String newText = new StringBuilder(parsedText[0]).append(" ").append(parsedText2[1]).toString();
ZoneId zone = ZoneId.of("Asia/Colombo");
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd h:mm:ss a", Locale.US)
.withZone(zone);
ZonedDateTime parsed = ZonedDateTime.parse(newText, formatter).plusNanos(Long.parseLong(parsedText2[0]) / 10);
System.out.println(parsed);

You just need to read it with SimpleDateFormatter:
System.out.println(sdf.format(date.getTime()));
If you want read it with default date format:
private static String[] daysOfWeek = new String[]{"SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"};
private static TimeZone tz = TimeZone.getTimeZone("Asia/Colombo");
private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS aa");
public static void main(String[] a){
try {
Calendar cal = Calendar.getInstance(tz);
sdf.setCalendar(cal);
cal.set(Calendar.AM_PM, Calendar.PM);
cal.setTime(sdf.parse("2018-11-02 6:05:59.1541162159 PM"));
System.out.println(
daysOfWeek[cal.get(Calendar.DAY_OF_WEEK)] +
new SimpleDateFormat(" dd hh:mm:ss yyyy").format(cal.getTime()));
}catch (Exception e){
e.printStackTrace();
}
}
Good luck.

Using Java SimpleDateFormat to find max date

I haven't programmed in Java for many years, but I now have to change a program I wrote some time ago. In this program I need to read a QIF file and find the qif record with the maximum date (Dmm-dd-yyyy).
I could not get this to work in my program so I wrote a simple test to demonstrate the problem I am having. I think there are other ways to do this, like lists and collections. But I still want to know why using SimpleDateFormat won't work. Notice in the output that this method produces the max for July but seems to ignore all August dates.
Thanks, Mike
import java.text.SimpleDateFormat;
import java.util.Date;
class DateParser {
public static void main(String[] args) {
SimpleDateFormat sdf = new SimpleDateFormat("mm-dd-yyyy");
Date nextDate = null;
Date maxDate = null;
String nextStrDate = null;
String maxStrDate = null;
//Fill date array.
String date[] = {"07-14-2014","07-22-2014","07-31-2014",
"08-01-2014","08-04-2014","08-06-2014"};
try {
//Start with early maximum date.
maxDate = sdf.parse("01-01-1800");
// Find Max date in array.
for (int i=0; i<6; ++i) {
nextStrDate = date[i];
nextDate = sdf.parse(nextStrDate);
if(nextDate.after(maxDate)){
maxStrDate = nextStrDate;
maxDate = nextDate;
}
System.out.println( "Next Date = " + nextStrDate);
}
System.out.println("\nMax Date = " + maxStrDate);
} catch (Exception e) {
System.out.println("Got error:" + e);
}
}
}
OUTPUT
Next Date = 07-14-2014
Next Date = 07-22-2014
Next Date = 07-31-2014
Next Date = 08-01-2014
Next Date = 08-04-2014
Next Date = 08-06-2014
Max Date = 07-31-2014

From the Java Docs....
m Minute in hour
What you want is
M Month in year
Change mm-dd-yyyy to MM-dd-yyyy

You format is incorrect, this
SimpleDateFormat sdf = new SimpleDateFormat("mm-dd-yyyy");
should be
SimpleDateFormat sdf = new SimpleDateFormat("MM-dd-yyyy");
because (per the SimpleDateFormat documentation),
Letter Date or Time Component Presentation Examples
...
M Month in year Month July; Jul; 07
...
m Minute in hour Number 30

Processing Java Strings and Dates

I need to process a list of Strings which may or may not be times. When I do receive a time, it will need to be converted from "HH:mm:ss" to number of milliseconds before processing:
final String unknownString = getPossibleTime();
final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
dateFormat.setLenient(false);
try {
final Date date = dateFormat.parse(unknownString);
//date.getTime() is NOT what I want here, since date is set to Jan 1 1970
final Calendar time = GregorianCalendar.getInstance();
time.setTime(date);
final Calendar calendar = GregorianCalendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, time.get(Calendar.HOUR_OF_DAY));
calendar.set(Calendar.MINUTE, time.get(Calendar.MINUTE));
calendar.set(Calendar.SECOND, time.get(Calendar.SECOND));
final long millis = calendar.getTimeInMillis();
processString(String.valueOf(millis));
}
catch (ParseException e) {
processString(unknownString);
}
This code works, but I really dislike it. The exception handling is particularly ugly. Is there a better way to accomplish this without using a library like Joda-Time?

public static long getTimeInMilliseconds(String unknownString) throws ParseException {
DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
String dateString = dateFormat.format(Calendar.getInstance().getTime());
DateFormat timeFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return timeFormat.parse(dateString + " " + unknownString).getTime();
}
Handle the ParseException outside of this method however you'd like. I.e. ("No time information provided"... or "unknown time format"... etc.)
.getTime() returns the time in milliseconds. It's part of the java.util.Date API.

Why don't you first check if the input is actually of HH:mm:ss format. You can do this by trying match input to regex [0-9]?[0-9]:[0-9]?[0-9]:[0-9]?[0-9] first and if it matches then treat it as date otherwise call processString(unknownString);

Change date format in a Java string

I've a String representing a date.
String date_s = "2011-01-18 00:00:00.0";
I'd like to convert it to a Date and output it in YYYY-MM-DD format.
2011-01-18
How can I achieve this?
Okay, based on the answers I retrieved below, here's something I've tried:
String date_s = " 2011-01-18 00:00:00.0";
SimpleDateFormat dt = new SimpleDateFormat("yyyyy-mm-dd hh:mm:ss");
Date date = dt.parse(date_s);
SimpleDateFormat dt1 = new SimpleDateFormat("yyyyy-mm-dd");
System.out.println(dt1.format(date));
But it outputs 02011-00-1 instead of the desired 2011-01-18. What am I doing wrong?

Use LocalDateTime#parse() (or ZonedDateTime#parse() if the string happens to contain a time zone part) to parse a String in a certain pattern into a LocalDateTime.
String oldstring = "2011-01-18 00:00:00.0";
LocalDateTime datetime = LocalDateTime.parse(oldstring, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.S"));
Then use LocalDateTime#format() (or ZonedDateTime#format()) to format a LocalDateTime into a String in a certain pattern.
String newstring = datetime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd"));
System.out.println(newstring); // 2011-01-18
Or, when you're not on Java 8 yet, use SimpleDateFormat#parse() to parse a String in a certain pattern into a Date.
String oldstring = "2011-01-18 00:00:00.0";
Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S").parse(oldstring);
Then use SimpleDateFormat#format() to format a Date into a String in a certain pattern.
String newstring = new SimpleDateFormat("yyyy-MM-dd").format(date);
System.out.println(newstring); // 2011-01-18
See also:
Java string to date conversion
Update: as per your failed attempt which you added to the question after this answer was posted; the patterns are case sensitive. Carefully read the java.text.SimpleDateFormat javadoc what the individual parts stands for. So stands for example M for months and m for minutes. Also, years exist of four digits yyyy, not five yyyyy. Look closer at the code snippets I posted here above.

Formatting are CASE-SENSITIVE so USE MM for month not mm (this is for minute) and yyyy
For Reference you can use following cheatsheet.
G Era designator Text AD
y Year Year 1996; 96
Y Week year Year 2009; 09
M Month in year Month July; Jul; 07
w Week in year Number 27
W Week in month Number 2
D Day in year Number 189
d Day in month Number 10
F Day of week in month Number 2
E Day name in week Text Tuesday; Tue
u Day number of week (1 = Monday, ..., 7 = Sunday) Number 1
a Am/pm marker Text PM
H Hour in day (0-23) Number 0
k Hour in day (1-24) Number 24
K Hour in am/pm (0-11) Number 0
h Hour in am/pm (1-12) Number 12
m Minute in hour Number 30
s Second in minute Number 55
S Millisecond Number 978
z Time zone General time zone Pacific Standard Time; PST; GMT-08:00
Z Time zone RFC 822 time zone -0800
X Time zone ISO 8601 time zone -08; -0800; -08:00
Examples:
"yyyy.MM.dd G 'at' HH:mm:ss z" 2001.07.04 AD at 12:08:56 PDT
"EEE, MMM d, ''yy" Wed, Jul 4, '01
"h:mm a" 12:08 PM
"hh 'o''clock' a, zzzz" 12 o'clock PM, Pacific Daylight Time
"K:mm a, z" 0:08 PM, PDT
"yyyyy.MMMMM.dd GGG hh:mm aaa" 02001.July.04 AD 12:08 PM
"EEE, d MMM yyyy HH:mm:ss Z" Wed, 4 Jul 2001 12:08:56 -0700
"yyMMddHHmmssZ" 010704120856-0700
"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'" 2001-07-04T12:08:56.235-0700
"yyyy-MM-dd'T'HH:mm:ss.SSSXXX" 2001-07-04T12:08:56.235-07:00
"YYYY-'W'ww-u" 2001-W27-3

The answer is of course to create a SimpleDateFormat object and use it to parse Strings to Date and to format Dates to Strings. If you've tried SimpleDateFormat and it didn't work, then please show your code and any errors you may receive.
Addendum: "mm" in the format String is not the same as "MM". Use MM for months and mm for minutes. Also, yyyyy is not the same as yyyy. e.g.,:
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
public class FormateDate {
public static void main(String[] args) throws ParseException {
String date_s = "2011-01-18 00:00:00.0";
// *** note that it's "yyyy-MM-dd hh:mm:ss" not "yyyy-mm-dd hh:mm:ss"
SimpleDateFormat dt = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
Date date = dt.parse(date_s);
// *** same for the format String below
SimpleDateFormat dt1 = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(dt1.format(date));
}
}

Why not simply use this
Date convertToDate(String receivedDate) throws ParseException{
SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy");
Date date = formatter.parse(receivedDate);
return date;
}
Also, this is the other way :
DateFormat df = new SimpleDateFormat("dd/MM/yyyy");
String requiredDate = df.format(new Date()).toString();
or
Date requiredDate = df.format(new Date());

Using the java.time package in Java 8 and later:
String date = "2011-01-18 00:00:00.0";
TemporalAccessor temporal = DateTimeFormatter
.ofPattern("yyyy-MM-dd HH:mm:ss.S")
.parse(date); // use parse(date, LocalDateTime::from) to get LocalDateTime
String output = DateTimeFormatter.ofPattern("yyyy-MM-dd").format(temporal);

[edited to include BalusC's corrections]
The SimpleDateFormat class should do the trick:
String pattern = "yyyy-MM-dd HH:mm:ss.S";
SimpleDateFormat format = new SimpleDateFormat(pattern);
try {
Date date = format.parse("2011-01-18 00:00:00.0");
System.out.println(date);
} catch (ParseException e) {
e.printStackTrace();
}

Please refer "Date and Time Patterns" here. http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html
import java.text.SimpleDateFormat;
import java.util.Date;
import java.text.ParseException;
public class DateConversionExample{
public static void main(String arg[]){
try{
SimpleDateFormat sourceDateFormat = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");
Date date = sourceDateFormat.parse("2011-01-18 00:00:00.0");
SimpleDateFormat targetDateFormat = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(targetDateFormat.format(date));
}catch(ParseException e){
e.printStackTrace();
}
}
}

Other answers are correct, basically you had the wrong number of "y" characters in your pattern.
Time Zone
One more problem though… You did not address time zones. If you intended UTC, then you should have said so. If not, the answers are not complete. If all you want is the date portion without the time, then no issue. But if you do further work that may involve time, then you should be specifying a time zone.
Joda-Time
Here is the same kind of code but using the third-party open-source Joda-Time 2.3 library
// © 2013 Basil Bourque. This source code may be used freely forever by anyone taking full responsibility for doing so.
String date_s = "2011-01-18 00:00:00.0";
org.joda.time.format.DateTimeFormatter formatter = org.joda.time.format.DateTimeFormat.forPattern( "yyyy-MM-dd' 'HH:mm:ss.SSS" );
// By the way, if your date-time string conformed strictly to ISO 8601 including a 'T' rather than a SPACE ' ', you could
// use a formatter built into Joda-Time rather than specify your own: ISODateTimeFormat.dateHourMinuteSecondFraction().
// Like this:
//org.joda.time.DateTime dateTimeInUTC = org.joda.time.format.ISODateTimeFormat.dateHourMinuteSecondFraction().withZoneUTC().parseDateTime( date_s );
// Assuming the date-time string was meant to be in UTC (no time zone offset).
org.joda.time.DateTime dateTimeInUTC = formatter.withZoneUTC().parseDateTime( date_s );
System.out.println( "dateTimeInUTC: " + dateTimeInUTC );
System.out.println( "dateTimeInUTC (date only): " + org.joda.time.format.ISODateTimeFormat.date().print( dateTimeInUTC ) );
System.out.println( "" ); // blank line.
// Assuming the date-time string was meant to be in Kolkata time zone (formerly known as Calcutta). Offset is +5:30 from UTC (note the half-hour).
org.joda.time.DateTimeZone kolkataTimeZone = org.joda.time.DateTimeZone.forID( "Asia/Kolkata" );
org.joda.time.DateTime dateTimeInKolkata = formatter.withZone( kolkataTimeZone ).parseDateTime( date_s );
System.out.println( "dateTimeInKolkata: " + dateTimeInKolkata );
System.out.println( "dateTimeInKolkata (date only): " + org.joda.time.format.ISODateTimeFormat.date().print( dateTimeInKolkata ) );
// This date-time in Kolkata is a different point in the time line of the Universe than the dateTimeInUTC instance created above. The date is even different.
System.out.println( "dateTimeInKolkata adjusted to UTC: " + dateTimeInKolkata.toDateTime( org.joda.time.DateTimeZone.UTC ) );
When run…
dateTimeInUTC: 2011-01-18T00:00:00.000Z
dateTimeInUTC (date only): 2011-01-18
dateTimeInKolkata: 2011-01-18T00:00:00.000+05:30
dateTimeInKolkata (date only): 2011-01-18
dateTimeInKolkata adjusted to UTC: 2011-01-17T18:30:00.000Z

try
{
String date_s = "2011-01-18 00:00:00.0";
SimpleDateFormat simpledateformat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S");
Date tempDate=simpledateformat.parse(date_s);
SimpleDateFormat outputDateFormat = new SimpleDateFormat("yyyy-MM-dd");
System.out.println("Output date is = "+outputDateFormat.format(tempDate));
} catch (ParseException ex)
{
System.out.println("Parse Exception");
}

You can just use:
Date yourDate = new Date();
SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd");
String date = DATE_FORMAT.format(yourDate);
It works perfectly!

public class SystemDateTest {
String stringDate;
public static void main(String[] args) {
SystemDateTest systemDateTest = new SystemDateTest();
// format date into String
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MM-yyyy hh:mm:ss");
systemDateTest.setStringDate(simpleDateFormat.format(systemDateTest.getDate()));
System.out.println(systemDateTest.getStringDate());
}
public Date getDate() {
return new Date();
}
public String getStringDate() {
return stringDate;
}
public void setStringDate(String stringDate) {
this.stringDate = stringDate;
}
}

String str = "2000-12-12";
Date dt = null;
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
try
{
dt = formatter.parse(str);
}
catch (Exception e)
{
}
JOptionPane.showMessageDialog(null, formatter.format(dt));

You could try Java 8 new date, more information can be found on the Oracle documentation.
Or you can try the old one
public static Date getDateFromString(String format, String dateStr) {
DateFormat formatter = new SimpleDateFormat(format);
Date date = null;
try {
date = (Date) formatter.parse(dateStr);
} catch (ParseException e) {
e.printStackTrace();
}
return date;
}
public static String getDate(Date date, String dateFormat) {
DateFormat formatter = new SimpleDateFormat(dateFormat);
return formatter.format(date);
}

You can also use substring()
String date_s = "2011-01-18 00:00:00.0";
date_s.substring(0,10);
If you want a space in front of the date, use
String date_s = " 2011-01-18 00:00:00.0";
date_s.substring(1,11);

private SimpleDateFormat dataFormat = new SimpleDateFormat("dd/MM/yyyy");
#Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
if(value instanceof Date) {
value = dataFormat.format(value);
}
return super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
};

remove one y form the format provide to:
SimpleDateFormat dt1 = new SimpleDateFormat("yyyyy-mm-dd");
It should be:
SimpleDateFormat dt1 = new SimpleDateFormat("yyyy-mm-dd");

We can convert Today's date in the format of 'JUN 12, 2020'.
String.valueOf(DateFormat.getDateInstance().format(new Date())));

/**
* Method will take Date in "MMMM, dd yyyy HH:mm:s" format and return time difference like added: 3 min ago
*
* #param date : date in "MMMM, dd yyyy HH:mm:s" format
* #return : time difference
*/
private String getDurationTimeStamp(String date) {
String timeDifference = "";
//date formatter as per the coder need
SimpleDateFormat sdf = new SimpleDateFormat("MMMM, dd yyyy HH:mm:s");
TimeZone timeZone = TimeZone.getTimeZone("EST");
sdf.setTimeZone(timeZone);
Date startDate = null;
try {
startDate = sdf.parse(date);
} catch (ParseException e) {
MyLog.printStack(e);
}
//end date will be the current system time to calculate the lapse time difference
Date endDate = new Date();
//get the time difference in milliseconds
long duration = endDate.getTime() - startDate.getTime();
long diffInSeconds = TimeUnit.MILLISECONDS.toSeconds(duration);
long diffInMinutes = TimeUnit.MILLISECONDS.toMinutes(duration);
long diffInHours = TimeUnit.MILLISECONDS.toHours(duration);
long diffInDays = TimeUnit.MILLISECONDS.toDays(duration);
if (diffInDays >= 365) {
int year = (int) (diffInDays / 365);
timeDifference = year + mContext.getString(R.string.year_ago);
} else if (diffInDays >= 30) {
int month = (int) (diffInDays / 30);
timeDifference = month + mContext.getString(R.string.month_ago);
}
//if days are not enough to create year then get the days
else if (diffInDays >= 1) {
timeDifference = diffInDays + mContext.getString(R.string.day_ago);
}
//if days value<1 then get the hours
else if (diffInHours >= 1) {
timeDifference = diffInHours + mContext.getString(R.string.hour_ago);
}
//if hours value<1 then get the minutes
else if (diffInMinutes >= 1) {
timeDifference = diffInMinutes + mContext.getString(R.string.min_ago);
}
//if minutes value<1 then get the seconds
else if (diffInSeconds >= 1) {
timeDifference = diffInSeconds + mContext.getString(R.string.sec_ago);
} else if (timeDifference.isEmpty()) {
timeDifference = mContext.getString(R.string.now);
}
return mContext.getString(R.string.added) + " " + timeDifference;
}

Say you want to change 2019-12-20 10:50 AM GMT+6:00 to 2019-12-20 10:50 AM
first of all you have to understand the date format first one date format is
yyyy-MM-dd hh:mm a zzz and second one date format will be yyyy-MM-dd hh:mm a
just return a string from this function like.
public String convertToOnlyDate(String currentDate) {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm a ");
Date date;
String dateString = "";
try {
date = dateFormat.parse(currentDate);
System.out.println(date.toString());
dateString = dateFormat.format(date);
} catch (ParseException e) {
e.printStackTrace();
}
return dateString;
}
This function will return your desire answer. If you want to customize more just add or remove component from the date format.

you have some wrong:
SimpleDateFormat dt1 = new SimpleDateFormat("yyyyy-mm-dd");
first :
should be
new SimpleDateFormat("yyyy-mm-dd");
//yyyy 4 not 5
this display 02011, but yyyy it disply 2011
second:
change your code like this
new SimpleDateFormat("yyyy-MM-dd");
i hope help you

java.time
In March 2014, modern date-time API* API supplanted the error-prone java.util date-time API and their formatting API, SimpleDateFormat. Since then it has been highly recommended to stop using the legacy API.
Also, quoted below is a notice from the home page of Joda-Time:
Note that from Java SE 8 onwards, users are asked to migrate to java.time (JSR-310) - a core part of the JDK which replaces this project.
You do not need DateTimeFormatter for formatting
You need DateTimeFormatter only for parsing your string but you do not need a DateTimeFormatter to get the date in the desired format. The modern Date-Time API is based on ISO 8601 and thus the toString implementation of java.time types return a string in ISO 8601 format. Your desired format is the default format of LocalDate#toString.
Solution using java.time, the modern Date-Time API:
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
public class Main {
public static void main(String[] args) {
String strDate = "2011-01-18 00:00:00.0";
DateTimeFormatter dtfInput = DateTimeFormatter.ofPattern("u-M-d H:m:s.S", Locale.ENGLISH);
LocalDateTime ldt = LocalDateTime.parse(strDate, dtfInput);
// Alternatively,
// LocalDateTime ldt = dtfInput.parse(strDate, LocalDateTime::from);
LocalDate date = ldt.toLocalDate();
System.out.println(date);
}
}
Output:
2011-01-18
ONLINE DEMO
Some important notes about the solution:
java.time made it possible to call parse and format functions on the Date-Time type itself, in addition to the traditional way (i.e. calling parse and format functions on the formatter type, which is DateTimeFormatter in case of java.time API).
Here, you can use y instead of u but I prefer u to y.
Learn more about the modern Date-Time API from Trail: Date Time.
* For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and How to use ThreeTenABP in Android Project.

SimpleDateFormat dt1 = new SimpleDateFormat("yyyy-mm-dd");

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