Daftar Isi

1. Pengantar Spring 6 dan Spring Boot 3
2. Persiapan Lingkungan dan Tools
3. Proyek 1: Aplikasi RESTful API Sederhana
4. Proyek 2: CRUD dengan Spring Data JPA
5. Proyek 3: Autentikasi dan Otorisasi dengan Spring Security
6. Proyek 4: Upload dan Download File
7. Proyek 5: Integrasi dengan Database NoSQL (MongoDB)
8. Proyek 6: Pengiriman Email Otomatis
9. Proyek 7: Deployment dan Monitoring Aplikasi
10. Sumber Belajar dan Source Code

Pengantar Spring 6 dan Spring Boot 3

Spring Framework adalah salah satu framework paling populer untuk pengembangan aplikasi Java. Versi terbaru, Spring 6, membawa banyak peningkatan performa dan dukungan untuk Java 17+. Spring Boot 3 memudahkan pengembangan aplikasi dengan konfigurasi minimal dan integrasi yang kuat.

Dalam ebook ini, Anda akan belajar langkah demi langkah membangun 7 proyek efektif menggunakan Spring 6 dan Spring Boot 3, mulai dari aplikasi RESTful sederhana hingga deployment dan monitoring.

Persiapan Lingkungan dan Tools

Sebelum memulai, pastikan Anda sudah menyiapkan beberapa tools berikut:

• Java Development Kit (JDK) versi 17 atau lebih baru
• IDE favorit seperti IntelliJ IDEA, Eclipse, atau VS Code
• Maven atau Gradle sebagai build tool
• Postman atau Insomnia untuk testing API
• Database seperti MySQL, PostgreSQL, atau MongoDB (tergantung proyek)

Anda juga bisa menggunakan Spring Initializr ( https://start.spring.io ) untuk membuat proyek Spring Boot dengan cepat.

Proyek 1: Aplikasi RESTful API Sederhana

Pada proyek pertama ini, kita akan membuat aplikasi RESTful API sederhana menggunakan Spring Boot 3 yang menyediakan endpoint untuk menampilkan daftar buku.

Langkah 1: Membuat Proyek Spring Boot

Gunakan Spring Initializr dengan konfigurasi berikut:

• Project: Maven Project
• Language: Java
• Spring Boot: 3.x.x
• Dependencies: Spring Web

Langkah 2: Membuat Model Buku

package com.example.demo.model;

public class Book {
    private Long id;
    private String title;
    private String author;

    public Book() {}

    public Book(Long id, String title, String author) {
        this.id = id;
        this.title = title;
        this.author = author;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }
}

      

Langkah 3: Membuat Controller

package com.example.demo.controller;

import com.example.demo.model.Book;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class BookController {

    @GetMapping("/books")
    public List getBooks() {
        return List.of(
            new Book(1L, "Spring in Action", "Craig Walls"),
            new Book(2L, "Pro Spring Boot 3", "Felipe Gutierrez"),
            new Book(3L, "Spring Microservices", "Rajesh RV")
        );
    }
}

      

Langkah 4: Menjalankan dan Menguji API

Jalankan aplikasi dan akses http://localhost:8080/books menggunakan browser atau Postman. Anda akan mendapatkan daftar buku dalam format JSON.

Proyek 2: CRUD dengan Spring Data JPA

Pada proyek ini, kita akan membuat aplikasi CRUD (Create, Read, Update, Delete) menggunakan Spring Data JPA dan database H2 untuk manajemen data buku.

Langkah 1: Tambahkan Dependencies

Tambahkan dependencies berikut di pom.xml :

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

      

Langkah 2: Konfigurasi application.properties

spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.h2.console.enabled=true
spring.jpa.hibernate.ddl-auto=update

      

Langkah 3: Buat Entity Book

package com.example.demo.entity;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;

@Entity
public class Book {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String title;
    private String author;

    public Book() {}

    public Book(String title, String author) {
        this.title = title;
        this.author = author;
    }

    // getters and setters
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }
}

      

Langkah 4: Buat Repository

package com.example.demo.repository;

import com.example.demo.entity.Book;
import org.springframework.data.jpa.repository.JpaRepository;

public interface BookRepository extends JpaRepository<Book, Long> {
}

      

Langkah 5: Buat Controller CRUD

package com.example.demo.controller;

import com.example.demo.entity.Book;
import com.example.demo.repository.BookRepository;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/api/books")
public class BookController {

    private final BookRepository bookRepository;

    public BookController(BookRepository bookRepository) {
        this.bookRepository = bookRepository;
    }

    @GetMapping
    public List<Book> getAllBooks() {
        return bookRepository.findAll();
    }

    @PostMapping
    public Book createBook(@RequestBody Book book) {
        return bookRepository.save(book);
    }

    @GetMapping("/{id}")
    public ResponseEntity<Book> getBookById(@PathVariable Long id) {
        return bookRepository.findById(id)
            .map(ResponseEntity::ok)
            .orElse(ResponseEntity.notFound().build());
    }

    @PutMapping("/{id}")
    public ResponseEntity<Book> updateBook(@PathVariable Long id, @RequestBody Book bookDetails) {
        return bookRepository.findById(id)
            .map(book -> {
                book.setTitle(bookDetails.getTitle());
                book.setAuthor(bookDetails.getAuthor());
                Book updated = bookRepository.save(book);
                return ResponseEntity.ok(updated);
            }).orElse(ResponseEntity.notFound().build());
    }

    @DeleteMapping("/{id}")
    public ResponseEntity<Void> deleteBook(@PathVariable Long id) {
        return bookRepository.findById(id)
            .map(book -> {
                bookRepository.delete(book);
                return ResponseEntity.noContent().build();
            }).orElse(ResponseEntity.notFound().build());
    }
}

      

Langkah 6: Testing CRUD API

Gunakan Postman untuk menguji endpoint:

• GET /api/books - Mendapatkan semua buku
• POST /api/books - Menambah buku baru (body JSON dengan title dan author)
• GET /api/books/{id} - Mendapatkan buku berdasarkan ID
• PUT /api/books/{id} - Mengupdate buku berdasarkan ID
• DELETE /api/books/{id} - Menghapus buku berdasarkan ID

Proyek 3: Autentikasi dan Otorisasi dengan Spring Security

Pada proyek ini, kita akan menambahkan fitur autentikasi dan otorisasi menggunakan Spring Security untuk mengamankan endpoint aplikasi.

Langkah 1: Tambahkan Dependency Spring Security

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-security</artifactId>
</dependency>

      

Langkah 2: Konfigurasi Security

package com.example.demo.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.web.SecurityFilterChain;

@Configuration
public class SecurityConfig {

    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        http
            .csrf().disable()
            .authorizeHttpRequests(auth -> auth
                .requestMatchers("/public/**").permitAll()
                .anyRequest().authenticated()
            )
            .httpBasic();
        return http.build();
    }
}

      

Langkah 3: Menambahkan User Detail Service Sederhana

package com.example.demo.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.provisioning.InMemoryUserDetailsManager;

@Configuration
public class UserConfig {

    @Bean
    public UserDetailsService userDetailsService() {
        var user = User.withDefaultPasswordEncoder()
            .username("user")
            .password("password")
            .roles("USER")
            .build();

        return new InMemoryUserDetailsManager(user);
    }
}

      

Langkah 4: Membuat Endpoint Public dan Private

package com.example.demo.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HomeController {

    @GetMapping("/public/hello")
    public String publicHello() {
        return "Hello, this is a public endpoint!";
    }

    @GetMapping("/private/hello")
    public String privateHello() {
        return "Hello, this is a secured endpoint!";
    }
}

      

Langkah 5: Testing Autentikasi

Akses /public/hello tanpa autentikasi, dan /private/hello dengan username user dan password password .

Proyek 4: Upload dan Download File

Pada proyek ini, kita akan membuat fitur upload dan download file menggunakan Spring Boot.

Langkah 1: Buat Controller untuk Upload dan Download

package com.example.demo.controller;

import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import java.net.MalformedURLException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

@RestController
@RequestMapping("/files")
public class FileController {

    private final Path storageLocation = Paths.get("uploads");

    public FileController() throws Exception {
        Files.createDirectories(storageLocation);
    }

    @PostMapping("/upload")
    public String uploadFile(@RequestParam("file") MultipartFile file) throws Exception {
        Path targetLocation = storageLocation.resolve(file.getOriginalFilename());
        Files.copy(file.getInputStream(), targetLocation);
        return "File uploaded: " + file.getOriginalFilename();
    }

    @GetMapping("/download/{filename}")
    public ResponseEntity<Resource> downloadFile(@PathVariable String filename) throws MalformedURLException {
        Path filePath = storageLocation.resolve(filename).normalize();
        Resource resource = new UrlResource(filePath.toUri());

        if (!resource.exists()) {
            return ResponseEntity.notFound().build();
        }

        String contentType = "application/octet-stream";

        return ResponseEntity.ok()
            .contentType(MediaType.parseMediaType(contentType))
            .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")
            .body(resource);
    }
}

      

Langkah 2: Testing Upload dan Download

Gunakan Postman untuk mengirim file ke endpoint POST /files/upload dan unduh file dengan GET /files/download/{filename} .

Proyek 5: Integrasi dengan Database NoSQL (MongoDB)

Pada proyek ini, kita akan menggunakan MongoDB sebagai database NoSQL dan mengintegrasikannya dengan Spring Boot.

Langkah 1: Tambahkan Dependencies MongoDB

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>

      

Langkah 2: Konfigurasi application.properties

spring.data.mongodb.uri=mongodb://localhost:27017/springbootdb

      

Langkah 3: Buat Entity dan Repository

package com.example.demo.model;

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

@Document(collection = "books")
public class Book {

    @Id
    private String id;

    private String title;
    private String author;

    public Book() {}

    public Book(String title, String author) {
        this.title = title;
        this.author = author;
    }

    // getters and setters
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }
}

      

package com.example.demo.repository;

import com.example.demo.model.Book;
import org.springframework.data.mongodb.repository.MongoRepository;

public interface BookRepository extends MongoRepository<Book, String> {
}

      

Langkah 4: Buat Controller CRUD MongoDB

package com.example.demo.controller;

import com.example.demo.model.Book;
import com.example.demo.repository.BookRepository;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/mongo/books")
public class BookMongoController {

    private final BookRepository bookRepository;

    public BookMongoController(BookRepository bookRepository) {
        this.bookRepository = bookRepository;
    }

    @GetMapping
    public List<Book> getAllBooks() {
        return bookRepository.findAll();
    }

    @PostMapping
    public Book createBook(@RequestBody Book book) {
        return bookRepository.save(book);
    }

    @GetMapping("/{id}")
    public ResponseEntity<Book> getBookById(@PathVariable String id) {
        return bookRepository.findById(id)
            .map(ResponseEntity::ok)
            .orElse(ResponseEntity.notFound().build());
    }

    @PutMapping("/{id}")
    public ResponseEntity<Book> updateBook(@PathVariable String id, @RequestBody Book bookDetails) {
        return bookRepository.findById(id)
            .map(book -> {
                book.setTitle(bookDetails.getTitle());
                book.setAuthor(bookDetails.getAuthor());
                Book updated = bookRepository.save(book);
                return ResponseEntity.ok(updated);
            }).orElse(ResponseEntity.notFound().build());
    }

    @DeleteMapping("/{id}")
    public ResponseEntity<Void> deleteBook(@PathVariable String id) {
        return bookRepository.findById(id)
            .map(book -> {
                bookRepository.delete(book);
                return ResponseEntity.noContent().build();
            }).orElse(ResponseEntity.notFound().build());
    }
}

      

Langkah 5: Testing MongoDB CRUD

Pastikan MongoDB berjalan di localhost:27017, lalu gunakan Postman untuk menguji endpoint CRUD di /mongo/books .

Proyek 6: Pengiriman Email Otomatis

Pada proyek ini, kita akan mengirim email otomatis menggunakan Spring Boot dan JavaMailSender.

Langkah 1: Tambahkan Dependency Spring Boot Starter Mail

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-mail</artifactId>
</dependency>

      

Langkah 2: Konfigurasi application.properties

spring.mail.host=smtp.gmail.com
spring.mail.port=587
spring.mail.username=your-email@gmail.com
spring.mail.password=your-app-password
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true

      

Langkah 3: Buat Service Pengiriman Email

package com.example.demo.service;

import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.stereotype.Service;

@Service
public class EmailService {

    private final JavaMailSender mailSender;

    public EmailService(JavaMailSender mailSender) {
        this.mailSender = mailSender;
    }

    public void sendSimpleEmail(String to, String subject, String text) {
        SimpleMailMessage message = new SimpleMailMessage();
        message.setFrom("your-email@gmail.com");
        message.setTo(to);
        message.setSubject(subject);
        message.setText(text);
        mailSender.send(message);
    }
}

      

Langkah 4: Buat Controller untuk Mengirim Email

package com.example.demo.controller;

import com.example.demo.service.EmailService;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class EmailController {

    private final EmailService emailService;

    public EmailController(EmailService emailService) {
        this.emailService = emailService;
    }

    @PostMapping("/send-email")
    public String sendEmail(
        @RequestParam String to,
        @RequestParam String subject,
        @RequestParam String body) {

        emailService.sendSimpleEmail(to, subject, body);
        return "Email sent to " + to;
    }
}

      

Langkah 5: Testing Pengiriman Email

Gunakan Postman untuk mengirim request POST ke /send-email dengan parameter to , subject , dan body .

Proyek 7: Deployment dan Monitoring Aplikasi

Pada proyek terakhir ini, kita akan membahas cara deployment aplikasi Spring Boot dan monitoring performa menggunakan Actuator.

Langkah 1: Tambahkan Dependency Spring Boot Actuator

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

      

Langkah 2: Konfigurasi application.properties

management.endpoints.web.exposure.include=health,info,metrics,httptrace

      

Langkah 3: Menjalankan Aplikasi dan Mengakses Endpoint Actuator

Jalankan aplikasi dan akses endpoint berikut:

• /actuator/health - Status kesehatan aplikasi
• /actuator/info - Informasi aplikasi
• /actuator/metrics - Statistik performa
• /actuator/httptrace - Trace HTTP request

Langkah 4: Deployment ke Heroku (Contoh)

Berikut langkah singkat deploy aplikasi ke Heroku:

1. Install Heroku CLI dan login dengan heroku login
2. Buat aplikasi baru dengan heroku create nama-aplikasi
3. Push kode ke Heroku dengan git push heroku main
4. Set konfigurasi environment jika perlu dengan heroku config:set
5. Akses aplikasi melalui URL yang diberikan Heroku

Sumber Belajar dan Source Code

Berikut beberapa sumber belajar dan repository source code yang bisa Anda gunakan untuk memperdalam pemahaman Spring 6 dan Spring Boot 3:

• Official Spring Boot Documentation
• Spring Guides (Tutorials resmi dari Spring)
• Repository Spring Boot di GitHub
• Baeldung - Tutorial Spring Boot Lengkap
• Channel YouTube Java Brains (Tutorial Spring Boot dan Java)
• Contoh Source Code 7 Proyek Spring Boot (GitHub)