Spring Data JPA - Query By Example

2023/06/27

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Spring Data JPA is a powerful tool for managing data in Java applications. One of its most useful features is Query By Example (QBE), which allows developers to easily construct queries based on the structure of their entities.

In a recent article, the author explains how to use QBE with Spring Data JPA. They start by showing how to create a simple entity class and repository interface. Then, they demonstrate how to use the QBE API to construct queries based on the properties of the entity.

The article also covers more advanced features of QBE, such as using nested properties and specifying match modes. The author provides code examples throughout the article to illustrate their points.

Overall, the article is a great resource for developers who want to learn more about using QBE with Spring Data JPA. By following the examples in the article, developers can quickly start building powerful queries that are tailored to their specific needs.

// Example entity class
@Entity
public class User {
  @Id
  private Long id;
  private String firstName;
  private String lastName;
  private int age;
  // getters and setters
}

// Example repository interface
public interface UserRepository extends JpaRepository<User, Long> {
  // Query By Example method
  List<User> findAll(Example<User> example);
}

// Example QBE query
User user = new User();
user.setFirstName("John");
user.setAge(30);
Example<User> example = Example.of(user);
List<User> users = userRepository.findAll(example);