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Java LocalDate format from reading from JSON and saving to Database

In as Spring Boot app, I am reading LocalDate from a JSON in dd/MM/yyyy format e.g. 15/03/2009 and while reading, I created them to a request. The format in the request is dd/MM/yyyy.
*ProductRequest:
#JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy")
private LocalDate buyingDate;
And then I save the date fields to database via my Entity. It also has the same format as shown below:
*ProductEntity:
#JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy")
private LocalDate buyingDate;
But the data in the database is shown in yyyy-MM-dd format. I think it is default format for LocalDate, but I need to be clarified about these points: Could you helps me please?
1. Does LocalDate always kept in yyyy-MM-dd format in the database independently from it had in JSON file and in Request?
2. As far as I see, the format while reading the data to ProductRequest is related to the usage when displaying data using this class (ProductRequest). IS that true?
3. Is there any need to use #JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy") for the date field in ProductEntity? As far as I see, it does not make any sense for the format when saving to database. So, if we do not display or use date field from this entity, then there is no need to use format annotation. Is that true?

Does LocalDate always kept in yyyy-MM-dd format in the database independently from it had in JSON file and in Request?
The JSON representation you use has nothing to do with how data is stored in the database[*]. Each database vendor (Oracle, MySQL, Postgres, SQLServer, etc) has its own way of storing date and date+time values. It's the job of your application or framework (eg, Hibernate) to translate from Java types such as LocalDate into the appropriate format for SQL statements. So the answer is "yes," the format of a date in the application is independent from how it's stored in a database.
As far as I see, the format while reading the data to ProductRequest is related to the usage when displaying data using this class (ProductRequest). IS that true?
Only if you serialize ProductRequest back out to JSON. #JsonFormat applies to both reading (deserializing) and writing (serializing) from/to JSON.
Is there any need to use #JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy") for the date field in ProductEntity? As far as I see, it does not make any sense for the format when saving to database. So, if we do not display or use date field from this entity, then there is no need to use format annotation. Is that true?
That is correct. In fact, it's very misleading to see that annotation in an entity[*]
[1] Unless you are using a database that natively understands JSON and/or stores data internally as JSON.

Always save date to today's date in database using jhipster

I have created one entity in jhipster using jhipster-jdl.jh file which is as shown below:
entity EmployeeLeave{
appliedDate LocalDate required,
fromDate LocalDate required,
toDate LocalDate required,
status String
}
From these fields i want appliedDate as today's date in database(MySql).
I have tried this from Angular side in jhipster code but none helps well.
Is there any way so that when creating a record for employeeLeave there should be always appliedDate equals to today's date.
Preferably i want solution from Angular side. Other solutions are also welcomed.
Technologies:
Database: Mysql,
Spring-boot,
Angular 4,
Jhipster.

You can initialize your date inside your class :
public class EmployeeLeave{
LocaleDate yourDate = LocaleDate.now();
//other fields
}
So, appliedDate will always be today's date. I am using Java 8 but the idea is here.

LocaleDate.now() is server time. If server is in another time zone than user, may insert incorrect date.
Isn't better to define date in .controller.js like:
var now = new Date();
vm.employeeLeave.appliedDate=now;
vm.isSaving = true;
EmployeeLeave.update(vm.employeeLeave, onSaveSuccess, onSaveError);
?

JSON date changed

I have a web application where user can post the message to a restful API, so that that information can be saved in the database.
My problem when the data is sent from the UI, the date sent is "effStartDate":"2016-08-13" , but when i see the date value in the java code it is showing Fri Aug 12 20:00:00 EDT 2016.
I am using AngularJS,Spring and iBatis as the ORM tool. Attached are the screen shots with data sent from UI and what i see in the backend code.
can anyone help me with this?

You can add annotations to realize in the entity.
(Have to rely on JackJson`s jar)
and Then add in required fields
"#JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone = "GMT+8")"

You can treat the date as a string. Something like this
#JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")

You can try this use date format from javascript code to send requests to a server by REST api.
For example:
effStartDate.toISOString();
The toISOString() method returns a string in simplified extended ISO format

GWT timezone issue

From few days I am fighting with different Timezone issues of server and GWT client. but cannot get any success.
Scenario is Server is in UTC timezone let say Client A is in IST timezone.
When client select a date (with time) I pushed to server but date is automatically changed to server's timezone. I dig around this issue and I found multiple solutions like
create custom serializer (No idea how to do that can't found any proper example)
transfer date as a string to server and convert it to server timezone and store it. and when fetching data convert again from server's timezone to client local timezone. sounds good idea.
So my query is.
Any other solutions?
which is best way to manage this ?
any sample code or link?

Simply format the date in UTC format at client side and pass the date as string to the server and store the data in UTC format in database as well.
On the server side everything would be fine, since formatting the date would use the timezone of the server, which is what the date is stored in. On the client side, however, GWT will use the timezone of the client machine, and so there could be a discrepancy.
Sample code:
DateTimeFormat f = DateTimeFormat.getFormat("MMM dd yyyy");
TimeZoneConstants t = (TimeZoneConstants) GWT.create(TimeZoneConstants.class)
TimeZone est = TimeZone.createTimeZone(t.americaNewYork());
int offset = est.isDaylightTime(date) ? +240 : +300;
TimeZone tz = TimeZone.createTimeZone(offset);
String date = f.format(user.getBirthDate(), est);
There are a few other possible solutions, but one of these two might do the trick.
How do I get GWT DateTimeFormat to display using the server TimeZone, rather than the client's?

Change the format of a date in a Web Service

i have table "news", that has a column called dateNews (type date )
in PostgreSQL the date has the following format : 2014-04-16
but in my jpa web service the format is the following : "2014-04-16T00:00:00+03:00"
how can i format my date to the following format : dd/mm/yyyy
and where should i do it is it in my PostgreSQL database or in my jpa web service ?

This conversion should be done in the service, not at the database level. Make sure your field is type java.sql.Date and use java.text.SimpleDateFormat.
see http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html
Main reasons to add this at the service level are extensibility and maintainability. You want a single point where you do all this formatting, probably based on user preferences. You don't want to add this to every query you are doing, and maintaining the format throughout those queries.

Use to_char() to output a formated string (text):
SELECT to_char(datenews, 'dd/mm/yyyy') FROM news;