jpa-repository | Repository programming model with JPA | Object-Relational Mapping library

I think you are looking for something that will generate a query like this

I wouldn't do something like this in the main method. Let Spring run and then add your configurations.

I would create a runner class that will do whatever I need once the Spring context is set up.

Example:

Now if you're using Java, there is none, but if you're using Javascript, you can use lowdb, a JSON database.

Try out this:

Finally, I fixed the problem using classes, in the httpClientService Angular module.

The problem is caused by using the ECB mode instead of the CBC mode in the posted code. To apply the CBC mode replace:

I think he wants you to use : https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#repositories.query-methods.query-property-expressions

Assume a Person has an Address with a ZipCode. In that case, the method creates the property traversal x.address.zipCode. The resolution algorithm starts by interpreting the entire part (AddressZipCode) as the property and checks the domain class for a property with that name (uncapitalized). If the algorithm succeeds, it uses that property

You convert your dtos to entities via dozer but as this point entities are still in detached-state.... to update existing entities you first need to load them through database via your repository. Something like repository.findById(Id id);

Then you will get entity in "attached" state and so state transitions(update on fields) will be applied.

During the save() all your entity state transitions will be translated to corresponding DML and your update should work now.

And regarding this statement

I'm not familiar with the getRepositoryFor method, but Optional is a standard Java class intruduced in Java SE 8. You can check if the value is present and get the actual value from the Optional if it is present. Here is a sample using orElseThrow, but there are also other variants. Checkout the Javadoc.