In previous posts, you've known how to use JPQL and native Query to retrieve data from the database using @Query annotation. Today, I will show you way to implement Spring Data JPA Repository query in Spring Boot with Derived Query methods:

Structure of Derived Query methods
Configure Spring Boot application to work with different database
JPA find by field, column name, multiple columns
JPA query methods for pagination and sorting

Full article: JPA Repository Query example

Structure of Derived Query methods

Typically, a Derived Query method has 2 elements: subject (the action), and predicate (the conditions).

Subject: is the introducing clause (find…By, exists…By, count…By for example), it may contain further expressions (between find/exists/count and By) for result-limiting keywords such as Distinct or Top/First.
Predicate: is placed after the subject. It can be entity properties (concatenating with And/Or) followed by one or more keywords (StartingWith, EndingWith, Containing, IgnoreCase...).

For example:

List&lt;Tutorial&gt; findByTitleContainingIgnoreCase(String title);

List&lt;Tutorial&gt; findTop3ByTitleContainingAndPublished(String title, boolean isPublished);

You can find the full list at query method subject keywords and query method predicate keywords.

JPA Repository Query example with Spring Boot

Technology:
- Java 8
- Spring Boot 2.6.3 (with Spring Data JPA)
- MySQL/PostgreSQL/H2 (embedded database)
- Maven 3.8.1

Project Structure:

Let me explain it briefly.

Tutorial data model class correspond to entity and table tutorials.
TutorialRepository is an interface that extends JpaRepository for derived query methods. It will be autowired in SpringBootQueryExampleApplication.
SpringBootQueryExampleApplication is SpringBootApplication which implements CommandLineRunner. We will use TutorialRepository to run Query methods here.
Configuration for Spring Datasource, JPA & Hibernate in application.properties.
pom.xml contains dependencies for Spring Boot and MySQL/PostgreSQL/H2 database.

Create Entity

In model package, we define Tutorial class.

Tutorial has four fields: id, title, level, description, published, createdAt.

model/Tutorial.java

package com.bezkoder.spring.jpa.query.model;

import javax.persistence.*;
import java.util.Date;

@Entity
@Table(name = "tutorials")
public class Tutorial {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private long id;

  private String title;

  private String description;

  private int level;

  private boolean published;

  @Temporal(TemporalType.TIMESTAMP)
  private Date createdAt;

  public Tutorial() {

  }

  public Tutorial(String title, String description, int level, boolean published, Date createdAt) {
    this.title = title;
    this.description = description;
    this.level = level;
    this.published = published;
    this.createdAt = createdAt;
  }

  // getters and setters
}

@Entity annotation indicates that the class is a persistent Java class.
@Table annotation provides the table that maps this entity.
@Id annotation is for the primary key.
@GeneratedValue annotation is used to define generation strategy for the primary key.
@Temporal annotation converts back and forth between timestamp and java.util.Date or time-stamp into time. For example, @Temporal(TemporalType.DATE) drops the time value and only preserves the date.

@Temporal(TemporalType.DATE)
private Date createdAt;

Define JPA Repository Query methods

Let's create a repository to interact with database.
In repository package, create TutorialRepository interface that extend JpaRepository.

repository/TutorialRepository.java

package com.bezkoder.spring.jpa.query.repository;

import com.bezkoder.spring.jpa.query.model.Tutorial;

public interface TutorialRepository extends JpaRepository<Tutorial, Long> {

}

In this interface, we will write JPA Derived Queries to fetch data from database with tutorials table like this:

For step by step and Github, please visit:
JPA Repository Query example

JPA Repository query example in Spring Boot | Derived Query

Structure of Derived Query methods

JPA Repository Query example with Spring Boot

Create Entity

Define JPA Repository Query methods

Further Reading