spring-todo

Todo app built with Spring Boot. Learn from tutorials: ithome ironman , section.io.

A to-do web app.

• Spring Boot
  • Spring Web
  • Spring Data JPA
  • Lombok
• React.js
• Axios

Followed the layered architecture described below to build it. A JAVA class to define the model. Create the repository interface by extending the CrudRepository. The service class defines the base CRUD operations. The REST API controller to communicate with the frontend.

• spring-todo
  • Usage
  • Architecture
    • DAO
  • Dependencies and Frameworks
    • H2 Database
    • Spring Boot DevTools
    • Lombok
    • Spring Data JPA
    • Junit
    • Mockito
    • MockMvc
    • JWT
  • Tools
    • Postman
    • Swagger
    • REST Client
  • Dependency Injection
    • Constructor-based
    • Setter-base
    • Field-base

Usage

Bring up spring server and frontend react server.

cd frontend/
npm i       # install dependency
npm start   # start react server

Architecture

• Presentation Layer
• Business Layer
• Presistence Layer
• Database

--

• Controller
• Service Layer
• DAO
• Database

DAO

Data Access Object. It provides an abstract interface and some specific data operations without exposing details of the database.

public interface TodoDao extends CrudRepository<Todo, Integer> {}

Dependencies and Frameworks

H2 Database

A in memory database. It has a console webpage.

Spring Boot DevTools

For hot reloading.

Lombok

Java annotation lib which helps to reduce boilerplate code.

Lombok - IntelliJ IDEA Plugin

• @Getter
• @Setter
• @NoArgsConstructor
• @ToString

Spring Data JPA

Java Persistence API. Hibernate is a ORM tool and an implementation of JPA.

javax.persistence.*

• @Entity
• @Table
• @Id
• @GeneratedValue
• @Column

Interface:

• Repository
• CrudRepository
• PagingAndSortingRepository
• JpaRepository

Junit

Run TEST with Coverage. (Element: Class% / Method% / Line%)

• org.junit.jupiter.api
• @Test
• assertEquals()

AAA patern:

• Arrange
• Act
• Assert

Mockito

A mocking framework for unit tests in Java.

MockMvc

Test web layer.

JWT

JSON Web Token. Usually for auth.

Tools

Postman

Postman is an API platform for building and using APIs.

Swagger

Swagger UI: Visualize OpenAPI Specification definitions.

REST Client

Method Request-URI HTTP-Version
Header-field: Header-value

Request-Body

• IntelliJ IDEA - HTTP Client

• VSCode - REST Client

Dependency Injection

• Constructor-based dependency injection
• Setter-based dependency injection
• Field-based dependency injection

@Component is an annotation that allows Spring to automatically detect our custom beans. Spring will:

• Scan our app for classes anntated with @Component
• Instantiate them and inject any specified dependencies into them
• Inject them wherever needed

Specialized Stereotype Annotations:

• @Controller
• @Service
• @Repository
• @Component
• @CustomComponent

Constructor-based

It is recommended for required dependencies allowing them to be immutable and preventing them to be null.

@Component
public class ConstructorBasedInjection {

    private final InjectedBean injectedBean;

    @Autowired
    public ConstructorBasedInjection(InjectedBean injectedBean) {
        this.injectedBean = injectedBean;
    }

}

Setter-base

It is recommended for optional dependencies.

@Component
public class ConstructorBasedInjection {

    private InjectedBean injectedBean;

    @Autowired
    public void setInjectedBean(InjectedBean injectedBean) {
        this.injectedBean = injectedBean;
    }

}

Field-base

Not recommended.

@Component
public class ConstructorBasedInjection {

    @Autowired
    private InjectedBean injectedBean;

}