Spring Boot findAll
Spring Boot findAll shows how to retrieve all entities using findAll method of the CrudRepository.
Spring Boot findAll
last modified July 18, 2023
Spring Boot findAll shows how to retrieve all entities using findAll method of the CrudRepository.
Spring is a popular Java/Kotlin application framework for creating enterprise applications. Spring Boot is an evolution of Spring framework which helps create stand-alone, production-grade Spring based applications with minimal effort.
CrudRepository
CrudRepository interface provides generic CRUD operations on a repository for a specific type. Its findAll method retrieves all entities of the type.
Spring Boot findAll example
The following application sets up a repository of City objects. In the console runner we retrieve city objects by their Ids.
build.gradle … src ├── main │ ├── java │ │ └── com │ │ └── zetcode │ │ ├── Application.java │ │ ├── MyRunner.java │ │ ├── model │ │ │ └── City.java │ │ ├── repository │ │ │ └── CityRepository.java │ │ └── service │ │ ├── CityService.java │ │ └── ICityService.java │ └── resources │ ├── application.properties │ ├── data-h2.sql │ └── schema-h2.sql └── test ├── java └── resources
This is the project structure.
build.gradle
plugins { id ‘org.springframework.boot’ version ‘3.1.1’ id ‘io.spring.dependency-management’ version ‘1.1.0’ id ‘java’ }
group = ‘com.zetcode’ version = ‘0.0.1-SNAPSHOT’ sourceCompatibility = ‘17’
repositories { mavenCentral() }
dependencies { implementation ‘org.springframework.boot:spring-boot-starter-data-jpa’ runtimeOnly ‘com.h2database:h2’ }
The build.gradle file contains dependencies for Spring Data JPA and H2 database.
resources/application.properties
spring.main.banner-mode=off spring.sql.init.platform=h2 spring.jpa.hibernate.ddl-auto=none
The application.properties is Spring Boot’s main configuration file. The Spring Boot banner is turned off with the spring.main.banner-mode property.
The spring.sql.init.platform sets the vendor name of the database. It is used in the initialization scripts. The spring.jpa.hibernate.ddl-auto disables the automatic creation of schemas from entities.
resources/schema-h2.sql
CREATE TABLE cities(id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(255), population INT);
When the application is started, the schema-h2.sql script is executed. It creates a new database table.
resources/data-h2.sql
INSERT INTO cities(name, population) VALUES(‘Bratislava’, 432000); INSERT INTO cities(name, population) VALUES(‘Budapest’, 1759000); INSERT INTO cities(name, population) VALUES(‘Prague’, 1280000); INSERT INTO cities(name, population) VALUES(‘Warsaw’, 1748000); INSERT INTO cities(name, population) VALUES(‘Los Angeles’, 3971000); INSERT INTO cities(name, population) VALUES(‘New York’, 8550000); INSERT INTO cities(name, population) VALUES(‘Edinburgh’, 464000); INSERT INTO cities(name, population) VALUES(‘Suzhou’, 4327066); INSERT INTO cities(name, population) VALUES(‘Zhengzhou’, 4122087); INSERT INTO cities(name, population) VALUES(‘Berlin’, 3671000);
The table is filled with data from the data-h2.sql file.
com/zetcode/model/City.java
package com.zetcode.model;
import jakarta.persistence.Entity; import jakarta.persistence.GeneratedValue; import jakarta.persistence.GenerationType; import jakarta.persistence.Id; import jakarta.persistence.Table;
import java.util.Objects;
@Entity @Table(name = “cities”) public class City {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
private int population;
public City() {
}
public City(String name, int population) {
this.name = name;
this.population = population;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getPopulation() {
return population;
}
public void setPopulation(int population) {
this.population = population;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
City city = (City) o;
return population == city.population &&
Objects.equals(name, city.name);
}
@Override
public int hashCode() {
return Objects.hash(name, population);
}
@Override
public String toString() {
var builder = new StringBuilder();
builder.append("City{id=").append(id).append(", name=")
.append(name).append(", population=")
.append(population).append("}");
return builder.toString();
}
}
This is the City entity.
com/zetcode/repository/CityRepository.java
package com.zetcode.repository;
import com.zetcode.model.City; import org.springframework.data.repository.CrudRepository; import org.springframework.stereotype.Repository;
@Repository public interface CityRepository extends CrudRepository<City, Long> {
}
By extending from the Spring CrudRepository, we have some basic methods for our data repository implemented.
com/zetcode/service/ICityService.java
package com.zetcode.service;
import com.zetcode.model.City;
public interface ICityService {
Iterable<City> findAll();
}
ICityService provides a contract method to retrieve all cities.
com/zetcode/service/CityService.java
package com.zetcode.service;
import com.zetcode.model.City; import com.zetcode.repository.CityRepository; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service;
@Service public class CityService implements ICityService {
private final CityRepository cityRepository;
@Autowired
public CityService(CityRepository cityRepository) {
this.cityRepository = cityRepository;
}
@Override
public Iterable<City> findAll() {
return cityRepository.findAll();
}
}
CityService contains the implementation of the findAll method. We use the repository to retrieve data from the database.
private final CityRepository cityRepository;
@Autowired public CityService(CityRepository cityRepository) { this.cityRepository = cityRepository; }
CityRepository is injected.
@Override public Iterable<City> findAll() {
return cityRepository.findAll();
}
The findAll returns the Iterable<City>.
com/zetcode/MyRunner.java
package com.zetcode;
import com.zetcode.service.ICityService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.CommandLineRunner; import org.springframework.stereotype.Component;
@Component public class MyRunner implements CommandLineRunner {
private final ICityService cityService;
@Autowired
public MyRunner(ICityService cityService) {
this.cityService = cityService;
}
@Override
public void run(String... args) throws Exception {
var cities = cityService.findAll();
cities.forEach(System.out::println);
}
}
In the MyRunner we retrieve all cities.
var cities = cityService.findAll(); cities.forEach(System.out::println);
We get all cities and print them to the console.
com/zetcode/Application.java
package com.zetcode;
import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
The Application sets up the Spring Boot application. The @SpringBootApplication enables auto-configuration and component scanning.
$ ./gradlew bootRun … City(id=1, name=‘Bratislava’, population=432000) City(id=2, name=‘Budapest’, population=1759000) City(id=3, name=‘Prague’, population=1280000) City(id=4, name=‘Warsaw’, population=1748000) City(id=5, name=‘Los Angeles’, population=3971000) City(id=6, name=‘New York’, population=8550000) City(id=7, name=‘Edinburgh’, population=464000) City(id=8, name=‘Suzhou’, population=4327066) City(id=9, name=‘Zhengzhou’, population=4122087) City(id=10, name=‘Berlin’, population=3671000) …
We run the application.
In this article we have showed how to find all entities using CrudRepository’s findAll method.
Author
My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.
