SpringBootを基本からまとめてみた【REST API】

spring initializrでプロジェクトを作成する

Maven

3.2.5

Group: com.codingshuffle
Artifact: tutorial
Name : Anuj
Description: Demo project for Spring Boot for Anuj
Package name: com.example

jar
Java 22

lombok
Spring Web
H2 Database

フォルダとファイルを作成する

(1)src/java/com/codingshuffle/tutorialにProdDBファイルを作成する

src/java/com/codingshuffle/tutorial/ProdDB.java

package com.codingshuffle.tutorial;

public class ProdDB implements DB {
    public String getData() {
        return "Prod Data";
    }
}

(2)src/java/com/codingshuffle/tutorial/AnujApplicationファイルを編集する

src/java/com/codingshuffle/tutorial/AnujApplication.java

package com.codingshuffle.tutorial;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class AnujApplication implements CommandLineRunner {

	@Autowired
	DB db;

	public static void main(String[] args) {
		SpringApplication.run(AnujApplication.class, args);
	}

	@Override
	public void run(String... args) throws Exception {
		System.out.println(db.getData());
	}
}

(3)src/java/com/codingshuffle/tutorialにDevDBファイルを作成する

src/java/com/codingshuffle/tutorial/DevDB.java

package com.codingshuffle.tutorial;

public class DevDB implements DB {
    public String getData() {
        return "Dev Data";
    }
}

(4)src/java/com/codingshuffle/tutorialにDBファイルを作成する

src/java/com/codingshuffle/tutorial/DB.java

package com.codingshuffle.tutorial;

public interface DB {
    public String getData();

    default String getDefaultData() {
        return "Default DB Data";
    }
}

(5)src/java/com/codingshuffle/tutorialにconfigurationフォルダと
AppConfigファイルを作成する

src/java/com/codingshuffle/tutorialにconfiguration/AppConfig.java

package com.codingshuffle.tutorial.configuration;

import com.codingshuffle.tutorial.DB;
import com.codingshuffle.tutorial.DevDB;
import com.codingshuffle.tutorial.ProdDB;
import org.springframework.context.annotation.Bean;
import org.modelmapper.ModelMapper;
import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;

@Configurable
public class AppConfig {

    @Bean
    @ConditionalOnProperty(name = "project.name", havingValue = "development")
    public DB getDevDBBean() {
        return new DevDB();
    }

    @Bean
    @ConditionalOnProperty(name = "project.name", havingValue = "production")
    public DB getProdDBBean() {
        return new ProdDB();
    }

    @Bean
    public ModelMapper getModelMapper() {
        return new ModelMapper();
    }
}

(6)resources/application.properties を編集する

resources/application.properties

spring.application.name=Anuj
project.mode=production
spring.h2.console.enabled=true
server.port=9000

(7)src/java/com/codingshuffle/tutorialにcontrollerフォルダと
EmployeeControllerファイルを作成する

src/java/com/codingshuffle/tutorial/controller/EmployeeController.java

package com.codingshuffle.tutorial.controller;

//Operation
//GET /employees
//POST /employees
//DELETE /employees/{id}

import com.codingshuffle.tutorial.dto.EmployeeDTO;
import com.codingshuffle.tutorial.service.EmployeeService;
import org.springframework.web.bind.annotation.*;
import java.util.List;

@RestController
@RequestMapping(path = "/employees")
public class EmployeeController {

    private final EmployeeService employeeService;

    public EmployeeController(EmployeeService employeeService) {
        this.employeeService = employeeService;
    }

    @GetMapping
    public List<EmployeeDTO> getAllEmployee() {
        return employeeService.getAllEmployees();
    }

    @GetMapping(path = "/{id}")
    public EmployeeDTO getEmployeeById(@PathVariable("id") Long employeeId) {
        return employeeService.getEmployeeById(employeeId);
    }

    @PostMapping
    public EmployeeDTO createNewEmployee(@RequestBody EmployeeDTO employeeDTO) {
        return employeeService.createNewEmployee(employeeDTO);
    }

    @DeleteMapping(path = "/{id}")
    public boolean deleteEmployeeById(@PathVariable Long id) {
        return employeeService.deleteEmployeeById(id);
    }
}

(8)src/java/com/codingshuffle/tutorialにdtoフォルダとEmployeeDTOファイルを作成する

src/java/com/codingshuffle/tutorial/dto/EmployeeDTO.java

package com.codingshuffle.tutorial.dto;

import com.fasterxml.jackson.annotation.JacksonProperty;
import com.fasterxml.jackson.annotation.JsonProperty;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.time.LocalDate;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class EmployeeDTO {
    private Long id;
    private String name;
    private LocalDate dateOfJoining;
    @JsonProperty("isActive")
    private boolean isActive;

}

(9)src/java/com/codingshuffle/tutorialにentitiesフォルダとEmployeeEntityファイルを作成する

src/java/com/codingshuffle/tutorial/entities/EmployeeEntity.java

package com.codingshuffle.tutorial.entities;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.Table;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.time.LocalDate;

@Entity
@Table(name = "employees")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class EmployeeEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String name;
    private LocalDate dateOfJoining;
    private boolean isActive;
}

(10)src/java/com/codingshuffle/tutorialにrepositoriesフォルダとEmployeeRepositoryファイルを作成する

src/java/com/codingshuffle/tutorialにrepositories/EmployeeRepository.java

package com.codingshuffle.tutorial.repositories;

import com.codingshuffle.tutorial.entities.EmployeeEntity;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface EmployeeRepository extends JpaRepository<EmployeeEntity, Long> {

}

(11)src/java/com/codingshuffle/tutorialにserviceフォルダとEmployeeServiceファイルを作成する

src/java/com/codingshuffle/tutorialにservice/EmployeeService.java

package com.codingshuffle.tutorial.service;

import com.codingshuffle.tutorial.dto.EmployeeDTO;
import com.codingshuffle.tutorial.entities.EmployeeEntity;
import com.codingshuffle.tutorial.repositories.EmployeeRepository;

import java.util.List;
import java.util.stream.Collectors;

import org.modelmapper.ModelMapper;
import org.springframework.stereotype.Service;

@Service
public class EmployeeService {

    final EmployeeRepository employeeRepository;
    final ModelMapper modelMapper;

    public EmployeeService(EmployeeRepository employeeRepository, ModelMapper modelMapper) {
        this.employeeRepository = employeeRepository;
        this.modelMapper = modelMapper;
    }

    public EmployeeDTO getEmployeeById(Long id) {
        EmployeeEntity employeeEntity = employeeRepository.getById(id);
        return modelMapper.map(employeeEntity, EmployeeDTO.class);

    }

    public EmployeeDTO createNewEmployee(EmployeeDTO employeeDTO) {
        EmployeeEntity employeeEntity = modelMapper.map(employeeDTO, EmployeeEntity.class);
        return modelMapper.map(employeeRepository.save(employeeEntity), EmployeeDTO.class);

    }

    public List<EmployeeDTO> getAllEmployee() {

        return employeeRepository
                .findAll()
                .stream()
                .map(employeeEntity -> modelMapper.map(employeeEntity, EmployeeDTO.class))
                .collect(Collectors.toList());
    }

    public boolean deleteEmployeeById(Long id) {
        boolean isPresent = employeeRepository.existsById(id);
        if (!isPresent)
            return false;
        employeeRepository.deleteById(id);
        return true;
    }
}

(12)pom.xmlを編集する

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>3.3.1</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>com.codingshuffle</groupId>
  <artifactId>tutorial</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>Anuj</name>
  <description>Demo project for Spring Boot for Anuj</description>
  <url/>
  <licenses>
    <license/>
  </licenses>
  <developers>
    <developer/>
  </developers>
  <scm>
    <connection/>
    <developerConnection/>
    <tag/>
    <url/>
  </scm>
  <properties>
    <java.version>22</java.version>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-data-jpa</artifactId>
	  </dependency>
	
    <dependency>
      <groupId>com.h2database</groupId>
      <artifactId>h2</artifactId>
    </dependency>

	<dependency>
		<groupId>org.modelmapper</groupId>
		<artifactId>modelmapper</artifactId>
		<version>3.0.0</version>
	</dependency>

    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <configuration>
          <excludes>
            <exclude>
              <groupId>org.projectlombok</groupId>
              <artifactId>lombok</artifactId>
            </exclude>
          </excludes>
        </configuration>
      </plugin>
    </plugins>
  </build>

</project>

参考サイト

Build REST APIs in Spring Boot as a Complete Beginner | 2 Hrs Crash Course | Bootcamp