Spring Boot Backend Development Course, Implementing Login and Logout with JWT, JWT

Hello! In this blog post, we will explain how to develop a backend service using Spring Boot and implement login and logout functions using JSON Web Token (JWT). JWT is a widely used method for transmitting and validating authentication information in web applications. Through this tutorial, we will explore the concept of JWT in detail and its implementation.

Table of Contents

  1. 1. JWT Concept
  2. 2. Spring Boot Project Setup
  3. 3. Entity Configuration
  4. 4. JWT Creation and Validation
  5. 5. Login Function Implementation
  6. 6. Logout Function Implementation
  7. 7. Comprehensive Test
  8. 8. Conclusion

1. JWT Concept

JWT (JSON Web Token) is a representative method for securely transmitting authentication information between two parties. JWT consists of three parts:

  • Header: Contains the type of token (JWT) and algorithm information.
  • Payload: Includes user information and other claims.
  • Signature: A signature created based on the Header and Payload, ensuring integrity.

The main advantage of JWT is that it allows information to be maintained on the client side, eliminating the need for the server to manage state. This is particularly useful in distributed systems or microservices architectures.

2. Spring Boot Project Setup

Let’s start by creating a simple RESTful API using Spring Boot. We will manage libraries using Maven.

pom.xml

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>jwt-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>jwt-demo</name>
    <description>JWT Demo Project</description>

    <properties>
        <java.version>17</java.version>
        <spring-boot.version>2.6.6</spring-boot.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt</artifactId>
            <version>0.9.1</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <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>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

After setting up the necessary dependencies as shown above, create the project directory and write the application class.

src/main/java/com/example/jwtdemo/JwtDemoApplication.java

package com.example.jwtdemo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

3. Entity Configuration

To manage users, we will configure a User entity. This entity is needed to store user information.

src/main/java/com/example/jwtdemo/model/User.java

package com.example.jwtdemo.model;

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

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String username;
    private String password;

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

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

4. JWT Creation and Validation

Now, let’s write a utility class to create and validate JWTs. This class will include methods to create and validate JWT tokens.

src/main/java/com/example/jwtdemo/util/JwtUtil.java

package com.example.jwtdemo.util;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Component
public class JwtUtil {
    private final String SECRET_KEY = "secret"; // Secret key
    private final int EXPIRATION_TIME = 1000 * 60 * 60; // 1 hour

    // Generate JWT
    public String generateToken(String username) {
        Map claims = new HashMap<>();
        return createToken(claims, username);
    }

    private String createToken(Map claims, String subject) {
        return Jwts.builder()
                .setClaims(claims)
                .setSubject(subject)
                .setIssuedAt(new Date(System.currentTimeMillis()))
                .setExpiration(new Date(System.currentTimeMillis() + EXPIRATION_TIME))
                .signWith(SignatureAlgorithm.HS256, SECRET_KEY)
                .compact();
    }

    // Validate JWT
    public boolean validateToken(String token, String username) {
        final String extractedUsername = extractUsername(token);
        return (extractedUsername.equals(username) && !isTokenExpired(token));
    }

    private boolean isTokenExpired(String token) {
        return extractExpiration(token).before(new Date());
    }

    private Date extractExpiration(String token) {
        return extractAllClaims(token).getExpiration();
    }

    private Claims extractAllClaims(String token) {
        return Jwts.parser().setSigningKey(SECRET_KEY).parseClaimsJws(token).getBody();
    }

    public String extractUsername(String token) {
        return extractAllClaims(token).getSubject();
    }
}

5. Login Function Implementation

Now we will implement the login function. If the user provides valid credentials, we will generate and return a JWT.

src/main/java/com/example/jwtdemo/controller/AuthController.java

package com.example.jwtdemo.controller;

import com.example.jwtdemo.model.User;
import com.example.jwtdemo.util.JwtUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.Map;

@RestController
@RequestMapping("/auth")
public class AuthController {
    @Autowired
    private JwtUtil jwtUtil;

    @PostMapping("/login")
    public Map login(@RequestBody User user) {
        // This part requires logic to check user information in the database.
        if ("test".equals(user.getUsername()) && "password".equals(user.getPassword())) {
            String token = jwtUtil.generateToken(user.getUsername());
            Map response = new HashMap<>();
            response.put("token", token);
            return response;
        } else {
            throw new RuntimeException("Invalid credentials");
        }
    }
}

6. Logout Function Implementation

Logout is typically performed by deleting or invalidating the JWT on the client side. Generally, logout is handled on the client side.

Here is an example of how to remove the JWT on the client:


localStorage.removeItem('token');

Since the server does not manage user state, there is no need for a separate logout endpoint on the server.

7. Comprehensive Test

Now that all implementations are complete, you can test the API using Postman or CURL.

  • Login Request: POST http://localhost:8080/auth/login – Send user information in JSON format in the Body.

{
    "username": "test",
    "password": "password"
}
response

{
    "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
}

You can use the received JWT to make other API calls by adding it to the Authorization header as Bearer.

8. Conclusion

In this tutorial, we learned how to implement login and logout functions using JWT with Spring Boot. JWT is a lightweight authentication mechanism that can be effectively applied in various situations. Using JWT in practice can enhance security through efficient authentication and authorization management. We recommend experiencing various features based on JWT in the future.

Thank you! Questions and feedback are welcome in the comments below.

Spring Boot Backend Development Course, What is JUnit

In modern software development, backend development is essential for providing users with a reliable and fast service experience. To enhance the efficiency of backend development, Spring Boot is widely used, and as a result, the testing framework JUnit has become an essential tool. This article will explore how to use JUnit in Spring Boot projects and its significance in detail.

1. What is Spring Boot?

Spring Boot is an extension of the Spring framework, providing tools that help developers easily build Spring applications with minimal configuration. It allows for rapid creation and execution of applications without complex XML configurations. Spring Boot supports embedded servers, making deployment easy, and it facilitates the management of dependencies through various starter packages.

1.1 Key Features of Spring Boot

  • Auto-Configuration: Spring Boot automatically configures settings based on the application’s dependencies.
  • Standalone: Applications can be run independently using the embedded server.
  • Starter Dependencies: Necessary libraries can be easily added through various starters.
  • Actuator: Helps to monitor and manage the application’s state.

2. What is JUnit?

JUnit is the most widely used unit testing framework designed for the Java programming language. JUnit provides features that simplify the writing, execution, and reporting of tests. By using JUnit, developers can quickly detect unexpected errors when making code changes and rectify them.

2.1 Key Features of JUnit

  • Annotation-based Testing: JUnit uses annotations to define test methods. For example, the @Test annotation is used to specify a test method.
  • Integration Testing Support: JUnit supports integration testing, allowing for tests to ensure that multiple components interact correctly.
  • Test Execution Order Specification: It allows specifying the execution order of specific test methods or managing test groups.
  • Exception Testing: Provides the ability to test whether specific methods throw exceptions.

3. Integration of Spring Boot and JUnit

When used together, Spring Boot and JUnit provide a powerful testing environment. Spring Boot uses JUnit to test various components of an application, ensuring software quality.

3.1 Setting Up JUnit in Spring Boot

To utilize JUnit in a Spring Boot project, the following configuration is necessary:

pom.xml

    
        org.springframework.boot
        spring-boot-starter-test
        test
    

By adding the spring-boot-starter-test dependency as shown above, various dependencies related to JUnit are automatically included.

3.2 Writing Basic Tests

Now let’s create a simple JUnit test. Below is an example of testing a Spring Boot REST controller:

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.web.servlet.MockMvc;

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@SpringBootTest
@AutoConfigureMockMvc
public class MyControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Test
    public void testGetEndpoint() throws Exception {
        mockMvc.perform(get("/api/my-endpoint"))
                .andExpect(status().isOk());
    }
}

In the above example, MockMvc is used to test the GET endpoint of a REST API. If the endpoint operates correctly, it should return an HTTP status code of 200.

4. Testing Strategies Using JUnit

Establishing effective testing strategies with JUnit is crucial in software development. Below are some strategies to consider when writing JUnit tests.

4.1 Unit Testing

Unit testing involves testing the functionality of individual modules or components. It verifies whether a specific method behaves correctly. Developers should write these unit tests alongside code to ensure no issues arise during subsequent changes or additions.

4.2 Integration Testing

Integration testing tests the interactions between multiple modules. For example, it verifies proper operation with a database connection, external API calls, etc. Integration tests play a significant role in enhancing performance and reliability.

4.3 Function Testing

Function testing verifies whether the software performs the required functions from the user’s perspective. By using JUnit and other testing tools together, it can be tested whether user requirements are satisfactorily met.

5. Combination of JUnit and Mockito

Combining JUnit and Mockito allows for a powerful testing environment. Mockito enables the creation of mock objects for the test subject, allowing for testing with isolation of dependencies while easily verifying if each component operates as expected.

5.1 JUnit Example with Mockito

import static org.mockito.Mockito.*;

import org.junit.jupiter.api.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;

public class MyServiceTest {

    @Mock
    private MyRepository myRepository;

    @InjectMocks
    private MyService myService;

    public MyServiceTest() {
        MockitoAnnotations.openMocks(this);
    }

    @Test
    public void testFindById() {
        when(myRepository.findById(1L)).thenReturn(Optional.of(new MyEntity(1L, "Test")));

        MyEntity entity = myService.findById(1L);

        assertNotNull(entity);
        assertEquals("Test", entity.getName());
    }
}

In the above code, Mockito is used to create a mock object of MyRepository, allowing the testing of MyService. By utilizing Mockito, dependencies can be eliminated for more specific test writing.

6. Best Practices for JUnit

Here are some best practices to achieve better testing results when using JUnit.

6.1 Tests Should Be Independent

Each test should be executed independently, ensuring that the result of one test does not affect another. To facilitate this, each test method should have proper initialization and cleanup.

6.2 Maintain Sufficient Test Coverage

It is crucial to maintain sufficient coverage by testing each feature of the software. Using JUnit, write tests for core business logic and validate major flows with integration tests.

6.3 Write Meaningful Test Cases

Instead of simply writing tests, strive to write meaningful test cases. This will help improve the quality of the application.

7. Conclusion

JUnit is an essential testing tool in the development of Spring Boot applications. By combining Spring Boot’s auto-configuration capabilities with JUnit’s easy test writing functionalities, an effective testing environment can be established. By appropriately utilizing unit tests, integration tests, and function tests, and isolating dependencies with tools like Mockito, higher-quality code can be achieved.

The importance of testing in software development is increasing, and JUnit plays a crucial role in ensuring software quality at its core. This article aims to assist in effectively utilizing JUnit in Spring Boot backend development.

Spring Boot Backend Development Course, What is CI CD?

In today’s software development environment, Spring Boot has established itself as an essential framework for building Java-based applications. This course aims to help you understand the basics of backend development using Spring Boot, and also to learn in detail about the concepts of CI/CD (Continuous Integration/Continuous Delivery).

1. What is Spring Boot?

Spring Boot is a tool that helps in easily developing Spring applications based on the Spring Framework. Its main purpose is to minimize configuration and support the rapid creation of applications that can run in production environments.

1.1. Features of Spring Boot

  • Autoconfiguration: Spring Boot automatically configures the settings required by the application, reducing the need for developers to manually write configuration files.
  • Standalone Applications: Spring Boot offers an embedded server, allowing it to be deployed as a standalone application without a WAR file or separate server configuration.
  • Starter Dependencies: It provides starter dependencies that pre-configure the dependencies of required libraries for various functionalities.
  • Production-ready Features: It includes various features such as metrics, health checks, and monitoring to enhance security in production environments.

2. Setting Up the Spring Boot Environment

To use Spring Boot, you must first set up your development environment. You need to install Java JDK, an IDE (e.g., IntelliJ IDEA or Eclipse), and Maven or Gradle.

2.1. Creating a Gradle or Maven Project

You can easily create a Spring Boot project using the Spring Initializr website (https://start.spring.io) or through your IDE. After creating a basic project, you can add dependencies according to the required functionalities.

2.2. Key Dependencies

The key dependencies to introduce for backend development include the following:

  • Spring Web: A module for building RESTful APIs.
  • Spring Data JPA: An ORM (Object-Relational Mapping) library for interacting with databases.
  • Spring Security: Manages authentication and authorization.
  • Spring Boot DevTools: Supports hot swapping (Modify and Reload) during development to speed up the development process.

3. Building a REST API with Spring Boot

Let’s understand the process of building a simple REST API using Spring Boot.

3.1. Creating an Entity Class

package com.example.demo.model;

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

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private String email;

    // getters and setters
}

3.2. Creating a Repository Interface

package com.example.demo.repository;

import com.example.demo.model.User;
import org.springframework.data.jpa.repository.JpaRepository;

public interface UserRepository extends JpaRepository<User, Long> {
}

3.3. Creating a Service Class

package com.example.demo.service;

import com.example.demo.model.User;
import com.example.demo.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;

    public List<User> getAllUsers() {
        return userRepository.findAll();
    }

    public User saveUser(User user) {
        return userRepository.save(user);
    }
}

3.4. Creating a Controller Class

package com.example.demo.controller;

import com.example.demo.model.User;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/api/users")
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping
    public List<User> getAllUsers() {
        return userService.getAllUsers();
    }

    @PostMapping
    public User createUser(@RequestBody User user) {
        return userService.saveUser(user);
    }
}

4. What is CI/CD?

CI/CD stands for Continuous Integration and Continuous Delivery/Deployment, which refers to a series of automated processes in software development. This approach automatically tests and deploys the application whenever a developer changes the code, making it a methodology that enhances efficiency and reduces errors.

4.1. Continuous Integration (CI)

Continuous Integration is a method where developers regularly (usually multiple times a day) integrate their code into a central repository. This practice allows for early detection of code changes, ensures that builds and tests are performed automatically, and improves quality. Key elements of CI include:

  • Version Control System: Using version control tools like Git or SVN to manage the history of code changes.
  • Automated Builds: Using CI tools such as Jenkins or CircleCI to automate the build process whenever code changes occur.
  • Automated Testing: Automated execution of unit tests, integration tests, etc., to verify the functioning of components.

4.2. Continuous Delivery/CD

Continuous Delivery is a process of automatically deploying new updates to the production environment. Applications that have been integrated through CI and have successfully passed testing are automatically deployed to the actual environment. CD is divided into two approaches:

  • Continuous Delivery: All changes are kept in a deployable state, but actual deployment is performed manually.
  • Continuous Deployment: All changes are automatically deployed to production, and deployment occurs automatically after passing tests.

5. CI/CD Tools

There are various CI/CD tools available. They can be chosen based on their different features and characteristics.

5.1. Jenkins

Jenkins is one of the most popular open-source CI/CD tools, providing infinite scalability through a variety of plugins. It supports pipeline DSL, allowing you to visually build CI/CD pipelines.

5.2. GitLab CI/CD

GitLab is a code repository platform with powerful CI/CD features built-in. With GitLab CI/CD, testing and deployment can occur instantly when code is pushed.

5.3. CircleCI

CircleCI is a cloud-based CI/CD tool that offers fast speed and easy setup. It allows for the easy configuration of complex pipelines using YAML files.

6. Integrating Spring Boot with CI/CD

Integrating Spring Boot applications into a CI/CD pipeline is very important. It typically includes the following steps:

  1. Connecting to a Code Repository: Connecting to platforms like GitHub or GitLab to detect code changes in real-time.
  2. Building and Testing: Building the code and performing automated tests to ensure code quality.
  3. Deployment: Deploying tested and verified code to the production environment.

7. Conclusion

The combination of backend development using Spring Boot and CI/CD plays a very important role in modern software development. It enables rapid development, high quality, and continuous deployment, significantly enhancing team productivity. Through this course, you will gain a basic understanding of Spring Boot and CI/CD and will be able to apply it to real projects.

8. References

Spring Boot Backend Development Course, JPA and Hibernate

Learn how to develop modern backend applications through a deep understanding of Spring Boot, JPA, and Hibernate (ORM).

1. What is Spring Boot?

Spring Boot is a lightweight application development framework based on the Spring framework. Designed to minimize configuration and enable rapid development, Spring Boot has established itself as a suitable framework for microservices architecture. It helps developers create applications more easily by replacing the complex Spring XML configurations.

The main features of Spring Boot are:

  • Auto Configuration: Automatically configures the necessary settings for the application.
  • Standalone: Supports an embedded servlet container, allowing it to run without a separate server.
  • Production-Ready: Provides various tools and configurations for operating the application by default.

2. What is JPA (Java Persistence API)?

JPA is a standard API that makes interaction with databases easier through ORM (Object-Relational Mapping) frameworks in Java. Based on object-oriented programming environments, JPA abstracts the operations with databases, enabling developers to access databases without writing SQL queries.

JPA offers the following key features:

  • Mapping between Objects and Relational Databases: Easily set up mappings between Java objects and database tables.
  • Transaction Management: Simplifies transaction management related to changes in database states.
  • Query Language: Provides an object-oriented query language called JPQL (Java Persistence Query Language) along with JPA.

3. What is Hibernate?

Hibernate is one of the most widely used implementations of JPA and is an advanced ORM tool. It helps to map Java objects to relational databases, making data processing easy and efficient. Hibernate offers performance optimization and a variety of features to manage data quickly and reliably, even in large applications.

The main features of Hibernate are:

  • Auto Mapping: Automatically handles the relationships between objects and databases.
  • Cache Management: Supports various caching mechanisms that enhance performance.
  • Support for Various Databases: Supports a variety of SQL databases and provides reliability even in multi-database environments.

4. Integration of Spring Boot, JPA, and Hibernate

In Spring Boot, it is easy to integrate and use JPA and Hibernate. Simply add the spring-boot-starter-data-jpa as a dependency and include database connection information in the application’s configuration file. This allows for the use of JPA and Hibernate without complex configurations.

For example, you can set it up in the application.properties file as follows:

spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=pass
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
            

5. Implementing Simple CRUD with Spring Boot

5.1 Creating a Project

Create a new Spring Boot project via Spring Initializr (https://start.spring.io/). Add the necessary dependencies and download the project to open it in your IDE.

5.2 Creating an Entity Class

Create an entity class to map to the database table using JPA. For example, let’s create an entity class called User.

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;
    private String email;

    // getters and setters
}
            

5.3 Creating a Repository Interface

Create a repository interface for the User class. Spring Data JPA will automatically generate the CRUD functions.

import org.springframework.data.jpa.repository.JpaRepository;

public interface UserRepository extends JpaRepository {
}
            

5.4 Creating a Service Class

Create a service class that handles the business logic.

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;

    public List findAll() {
        return userRepository.findAll();
    }

    public User save(User user) {
        return userRepository.save(user);
    }
}
            

5.5 Creating a REST Controller

Create a controller to provide the RESTful API. It processes user requests and calls the service.

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/api/users")
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping
    public List getAllUsers() {
        return userService.findAll();
    }

    @PostMapping
    public User createUser(@RequestBody User user) {
        return userService.save(user);
    }
}
            

6. Advanced Features of JPA

With JPA, you can use a variety of features beyond basic CRUD. Let’s take a look at some key features:

6.1 JPQL (Java Persistence Query Language)

JPQL is an object-oriented query language provided by JPA. Using JPQL, you can write queries based on objects, making it more intuitive than SQL queries.

List users = entityManager.createQuery("SELECT u FROM User u WHERE u.name = :name", User.class)
        .setParameter("name", "John")
        .getResultList();
            

6.2 @Query Annotation

In JPA, you can define custom queries using the @Query annotation on methods.

import org.springframework.data.jpa.repository.Query;

public interface UserRepository extends JpaRepository {
    @Query("SELECT u FROM User u WHERE u.email = ?1")
    User findByEmail(String email);
}
            

6.3 Paging and Sorting

Spring Data JPA provides features for easily handling paging and sorting. You can inherit methods in your created repository interface from PagingAndSortingRepository.

public interface UserRepository extends PagingAndSortingRepository {
}
            

7. Advanced Features of Hibernate

Hibernate offers various features related to performance tuning and databases. For example, caching management, batch processing, and multi-database support can significantly enhance application performance.

7.1 First-Level Cache and Second-Level Cache

Hibernate uses a first-level cache by default, storing data retrieved within the same session in memory to improve performance. The second-level cache is a cache shared across multiple sessions, which can optimize performance.

7.2 Batch Processing

Hibernate supports batch processing for handling large volumes of data at once. This minimizes the number of database connections and improves performance.

8. Conclusion

Spring Boot, JPA, and Hibernate are powerful tools for modern backend application development. Through this course, you will gain a broad knowledge from fundamental understanding of Spring Boot to database processing using JPA and Hibernate. I hope you will apply this in real projects and gain deeper experience.

Spring Boot Backend Development Course, What is AWS

1. Introduction

In today’s web application development, a variety of technology stacks exist. Among them, Spring Boot, an efficient web framework based on Java, and AWS (Amazon Web Services), the epitome of cloud services, are loved by many developers. This article aims to explore the basics of backend development using Spring Boot and its integration with AWS.

2. What is Spring Boot?

Spring Boot is a Java-based framework built on the Spring framework. This framework reduces the complexity of the existing Spring framework and enables more concise and faster development. Spring Boot automatically configures various settings, allowing developers to focus on business logic.

2.1 Features

  • Auto Configuration: Developers can easily build enterprise-level Spring applications without complex XML configuration.
  • Standalone: Spring Boot applications can run independently without the need to be deployed on an external server.
  • Consistent Deployment: Applications can be easily packaged as jar files for deployment.
  • Starter Dependencies: Various starters allow for the easy addition of required libraries.

3. Installing Spring Boot and Setting Up the Environment

The requirements for using Spring Boot are as follows:

3.1 Requirements

  • Java Development Kit (JDK) 8 or higher
  • IDE (IntelliJ, Eclipse, etc.)
  • Maven or Gradle

3.2 Creating a Project

You can create a new Spring Boot project using Spring Initializr. Select the required dependencies and set up the Java version, group, artifact, etc., to generate the project.

4. Building a RESTful API

Building a RESTful API using Spring Boot is very straightforward. We will define the API through the following process.

4.1 Creating a Controller


@RestController
@RequestMapping("/api")
public class UserController {

    @GetMapping("/users")
    public List getAllUsers() {
        // Return the list of users
    }
}
        

4.2 Implementing Service and Repository Layers

Create a service class to handle business logic and implement a repository for interaction with the database.

5. What is AWS?

AWS (Amazon Web Services) is a cloud computing service provided by Amazon. Businesses can utilize AWS for data storage, analysis, deployment, and management services. AWS operates data centers worldwide and provides reliable and scalable cloud services to numerous users.

5.1 Key Services of AWS

  • EC2: Elastic Compute Cloud, providing virtual servers.
  • S3: Simple Storage Service, allowing for file storage and management.
  • RDS: Relational Database Service, offering managed database services.
  • Lambdas: Simplifies code execution through serverless computing.

6. Integration of Spring Boot and AWS

The process of deploying a Spring Boot application to AWS is as follows:

6.1 Deploying to AWS EC2

After packaging the Spring Boot application as a jar file, you can deploy it to an AWS EC2 instance. Create an EC2 instance, configure the environment, and then transfer the jar file to execute it.

6.2 Hosting Static Files on AWS S3

You can manage and deploy static files of your web application using AWS S3. This method is efficient and cost-effective.

7. Conclusion

Spring Boot and AWS play a very important role in modern web application development. With these tools, developers can develop and deploy applications more quickly and efficiently. We will continue to provide deeper knowledge through various courses and examples, so please stay tuned.

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