How to return specific object attributes in spring boot queries with DAO?

user_3476509 0
Viewed 1114

in my Spring Boot application I have an entity called Person.class, which contains

long id;
String email;
String name;
String surname;
String address;

In the DAO class, I have a method:

List<Person> findAllByEmail(String email);

Which queries the Database and returns a list of Person.

I would like to return a list of Person with just some attributes, for example:

long id;
String email;

Without return the entire object.

This would be equivalent to execute the query:

"select id, email from person where email = ?"

But I would like to maintain the function query into the DAO as

List<Person> findAllByEmail(String email);

Without writing the queries by hand.

How can I do it ?

spring-boot dao api spring java
2 Answers

Returning multiple values from a method is not possible. In your calling method, when iterating over the returned List<Person>, you should read the required fields from each Person out of the List into local variables and work with those.

user_144923280

You can use JPA Projections

  1. Create interface with getters of desired columns
interface WithIdAndEmail {
   long getId();
   String getEmail();
}
  1. Use that interface as the return type of the method
List<WithIdAndEmail> findAllByEmail(String email);
user_22240470
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