Query on Date only with Spring Boot Data JPA / Java 8 Instant?

By : Busata
Source: Stackoverflow.com
Question!

I have a Spring boot 1.4.x application that uses the starter jpa in combination with H2/Postgresql. I have an entity that stores a date as an Instant (with Instant.now(), based on Java 8: What's the difference between Instant and LocalDateTime? answer), and the associated table stores this field as a timestamp.

For the storing to work I had to setup a converter that converts Instant's to sql.Timestamps & vice versa, which seems to work (Timestamp.from(instant) and timestamp.toInstant())

My question is if there is a straightforward way to query by Date only using this instant using JPA repository, eg.

List<Orders> findBySaleTime(.... day)

Or am I forced to find a way to convert the day to two instants & do an in between query?

By : Busata


Answers
public List<SaleOrder> findByDate(String date) {
    Instant startOfDay = Instant.parse(date).truncatedTo(ChronoUnit.DAYS);
    Instant endOfDay = startOfDay.plus(Duration.ofDays(1));

    return saleOrderRepository.findBySaleTimeAfterAndSaleTimeBefore(startOfDay, endOfDay);
}

Where the date is an UTC date passed from the client, seems to be the most straightforward to do this with java 8 dates. (Credits to Liste & Yawkat on freenode #java for help/pointers)

By : Busata


There are two approaches:

1st one:

List<Orders> findBySaleTimeBetween(DateTime start, DateTime end);

2nd one:

List<Orders> findBySaleTime(DateTime date);

It's worth trying to save dates rounded as much as possible, so if you only need day, set hours and minutes to certain values for all the entities.

By : xenteros


You can use a WHERE clause for this. Convert your INSERT VALUES to an INSERT SELECT and add a WHERE clause.

For example,

INSERT INTO fields (field_name, control_type_id, needs_approval)
SELECT
'Array Photos', 3, 0
WHERE Condition;

If Condition is true, it will insert the row. If Condition is false, the SELECT will return zero rows and thus the INSERT will insert zero rows.



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By: admin