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Spring Web Presentation - Framework and Its Ecosystem
- 1. Spring Web -Dobrin Horia -Lefter Maria Izabela -Manolache Antonia -Maxim Robert-Gabriel 28th October 2024
- 2. Overview of the Spring Framework and Its Ecosystem The Spring Framework • Definition: Spring is an open-source application framework written in Java and initially created by Rod Johnson in 2003. It provides comprehensive infrastructure support for Java applications, primarily for enterprise-level development. • Purpose: It simplifies the development process by providing an array of tools for managing the complexity of enterprise applications. It offers configurations for managing the components and services, helping developers focus more on business logic rather than boilerplate code.
- 3. Core Aspects of Spring • Inversion of Control (IoC): • Explanation: IoC is a design principle where the control of object creation and dependency management is passed to a container (the Spring Framework) instead of being hard-coded. Spring uses IoC to create and manage objects, freeing developers from directly handling dependencies. • Dependency Injection (DI): A specific type of IoC where dependencies are injected into an object at runtime, enhancing modularity and testability. For example, instead of creating a new instance of a class, it can be injected into another class that needs it.
- 4. • Aspect-Oriented Programming (AOP): • Explanation: AOP is a programming approach that allows the separation of cross- cutting concerns (such as logging, transaction management, and security) from business logic, keeping code clean and focused. • Example: Instead of writing logging code in every method, AOP allows you to define logging logic separately and apply it as an aspect across different parts of the application.
- 5. • Spring Boot: • Purpose: Spring Boot is an extension of Spring, designed to simplify application setup, especially for web applications. It provides embedded servers, like Tomcat, and preconfigured settings, reducing the need for complex configurations. • Why It Matters: Spring Boot lets developers create production-ready applications quickly. For example, you can start a web server with minimal configuration, streamlining the development process. • Spring Modules and Extensions: • Additional Modules: Spring Security (for authentication and authorization), Spring Data (for data access), Spring Batch (for batch processing), and Spring Web (for web application development).
- 6. Importance of Spring Web within the Framework Spring Web Module • Overview: Spring Web is a core component of the Spring Framework that provides the essential tools for building robust web applications. It’s built around the Model-View- Controller (MVC) pattern, which separates the application into three interconnected components. • MVC Architecture: • Model: Represents the data or business logic of the application. • View: The user interface (UI), displaying data and receiving user input. • Controller: Manages interactions between the Model and the View, processing user input and updating the View.
- 7. • Spring Boot Integration with Spring Web: • Spring Boot simplifies setting up Spring Web applications by offering preconfigured templates, embedded servers, and auto- configuration. This integration enables faster, more efficient development cycles. • Spring Web’s Role in RESTful Applications: • REST Support: Spring Web supports REST (Representational State Transfer), a popular architectural style for APIs that allows web services to communicate over HTTP. This makes Spring Web ideal for developing REST APIs, which are widely used in modern web applications and microservices.
- 8. Key Benefits of Using Spring for Web Development Advantages of Spring for Web Development: • Modularity: Spring's modular design allows developers to include only the modules they need, keeping applications lightweight and efficient. • Dependency Injection: • Why it’s Important: DI makes code easier to manage and test by allowing classes to receive dependencies from an external source rather than creating them internally. • Example: Suppose you have a service class that depends on a data access class. With DI, Spring automatically injects this dependency, decoupling the classes and enabling flexible testing. • Ease of Testing: • Testing Support: Spring includes robust testing support, including JUnit and MockMvc, a tool for testing web controllers. • Example: MockMvc allows testing of Spring MVC controllers without launching a web server, making unit and integration testing easier. • Community and Documentation: • Overview: Spring has an active and supportive community, vast online resources, and comprehensive documentation. This support network makes troubleshooting and knowledge sharing accessible, which is essential for project scalability and new developers. • Versatility: • Applications: Spring’s flexibility allows it to support a wide variety of applications, from traditional monolithic apps to modern microservices. • Example: A company using Spring can start with a monolithic architecture and gradually transition to microservices, reusing much of the same code base due to Spring’s modularity.
- 9. Applications and Industries Where Spring Web is Commonly Used Industry-Specific Applications of Spring Web: • E-commerce: • Example: Companies like Amazon and eBay use Spring for managing large transaction volumes, handling thousands of concurrent users, and implementing search and payment gateways. • Finance and Banking: • Example: Banks use Spring for handling sensitive data, managing transactions, and implementing secure APIs for mobile and web applications. • Spring Security: An extension often used in these industries for secure authentication and authorization. • Healthcare: • Example: Many healthcare providers use Spring for patient management systems, appointment scheduling, and data protection compliant with standards like HIPAA. • Telecommunications: • Example: Companies rely on Spring to build applications that can handle massive user data, handle customer management, and facilitate seamless communication channels.
- 10. Set Up Spring Initializr What is Spring Initializr? • Definition: Spring Initializr is a web-based tool provided by the Spring team to quickly bootstrap a new Spring Boot project with necessary configurations and dependencies. • URL: You can access it at start.spring.io. • Purpose: It simplifies the initial setup of Spring applications by generating a project structure with essential files and dependencies, allowing developers to get started immediately without manual configuration. • Advantages of Using Spring Initializr: • Speeds Up Project Setup: No need to configure dependencies and project structure manually, allowing developers to focus on coding immediately. • Predefined Dependencies: Ensures all necessary dependencies and plugins are added without conflicts, reducing errors. • Updated Best Practices: Spring Initializr provides a project structure and dependency versions that align with the latest best practices and standards from the Spring community.
- 11. How to Use Spring Initializr 1. Go to the Website: Visit start.spring.io. 2. Choose Project Metadata: • Project: Select Maven or Gradle based on your preference. • Language: Java is the default option, but Kotlin and Groovy are also supported. • Spring Boot Version: Choose the latest stable Spring Boot version. • Group and Artifact: These define your project’s namespace. The Group is usually the organization or company name (e.g., com.example), and the Artifact is the project name (e.g., product-api). 3. Select Dependencies: Spring Initializr offers a wide array of dependencies. For a Spring Web application, the common choices include: • Spring Web: For building web applications with Spring MVC. • Spring Boot DevTools: For hot reloading, making development faster. • Spring Data JPA: For database integration and JPA (Java Persistence API) support. • Spring Security (if needed): For authentication and authorization. 4. Download and Unpack: Click Generate to download the ZIP file. Unzip it and open the project in your preferred IDE (e.g., IntelliJ IDEA, Eclipse, or VS Code).
- 12. Dependencies • Dependencies provide functionality that developers can use in their projects without writing everything from scratch. For example: • Instead of writing code to handle HTTP requests and responses, you can use the Spring Web dependency, which provides this functionality. • Instead of building a system to interact with a database from scratch, you can use Spring Data JPA, which simplifies database interactions and supports ORM (Object-Relational Mapping). • By including these dependencies in your project, you get access to pre-written classes and methods that handle common tasks, saving time and reducing potential errors.
- 13. Examples Dependency Purpose Use Case Spring Web Build web apps and RESTful APIs Essential for web development and REST APIs Spring Boot DevTools Hot reloading and dev-time optimizations Speeds up development Spring Data JPA ORM and database interactions For relational database access Spring Security Authentication and authorization For securing endpoints and managing users Thymeleaf Server-side HTML templating For building dynamic HTML views Spring Boot Starter Test Provides testing support Essential for unit and integration testing Spring Boot Actuator Monitoring and managing production apps For application health and metrics monitoring
- 14. Core Components of Spring Web 1. DispatcherServlet • Overview: The DispatcherServlet is the central component of the Spring Web MVC framework. It acts as the front controller, receiving incoming HTTP requests and delegating them to the appropriate handler (controller). • How It Works: • Request Routing: When a request comes in, DispatcherServlet examines the URL pattern and determines which controller method should handle it. • Handler Mapping: The DispatcherServlet consults handler mappings to match incoming requests to their corresponding handlers (controllers). • View Resolution: After the controller processes the request, the DispatcherServlet selects an appropriate view (e.g., JSP, Thymeleaf) to render the response. • Example Flow: • A user sends a request to /product/details. • DispatcherServlet intercepts the request and uses handler mapping to direct it to a ProductController. • After processing, it determines the view (e.g., a JSP page or a Thymeleaf template) to send back to the user. • Benefits: It centralizes request processing, reduces complexity, and improves modularity within the application by clearly separating request routing and handling.
- 15. 2. Controllers • Role of Controllers: Controllers are responsible for handling HTTP requests, processing data, and returning appropriate responses. They contain the business logic and define how requests should be handled. • @Controller Annotation: • Purpose: Marks a class as a Spring MVC controller. • Functionality: Each method within a @Controller class typically represents an endpoint (URL pattern) and processes HTTP requests (e.g., GET, POST). • Request Mapping: @RequestMapping is used to map URLs to specific methods within the controller, ensuring each request is routed to the correct logic. • Advantages: Organizes the application logic, making it modular and maintainable, as each controller is focused on a specific area (e.g., products, users).
- 16. 3. Views • Overview: Views are responsible for presenting data to the user. In Spring Web MVC, views are typically HTML pages created with a templating engine (e.g., JSP or Thymeleaf). • Types of View Templates: • JSP (JavaServer Pages): A popular, Java-based template engine often used with Spring MVC. JSP files mix HTML with Java code to dynamically generate content. • Thymeleaf: A modern templating engine specifically designed for Spring applications. It offers a more natural way to generate dynamic HTML content and is more flexible and powerful than JSP. • View Resolver: Spring’s view resolver component is responsible for mapping logical view names (like “productDetails”) to actual view templates (like productDetails.html). • Benefits: View templates separate presentation logic from application logic, allowing frontend developers to work independently on UI design without altering the backend code.
- 17. 4. REST Controllers • Overview: Unlike standard controllers that return views, REST controllers are designed to return data, typically in JSON or XML format, making them ideal for RESTful web services and APIs. • @RestController Annotation: • Purpose: Marks a class as a RESTful controller, meaning each method returns data directly to the client, usually in JSON format. • Key Difference from @Controller: Instead of returning a view, a @RestController method returns data (e.g., JSON or XML), which is usually consumed by frontend applications or other systems. • RESTful Endpoints: • GET: Used to retrieve data. Example: GET /api/products returns a list of products. • POST: Used to create new resources. Example: POST /api/products adds a new product. • PUT: Used to update existing resources. Example: PUT /api/products/1 updates product with ID 1. • DELETE: Used to delete resources. Example: DELETE /api/products/1 deletes product with ID 1. • JSON Support: By default, Spring uses the Jackson library to automatically convert Java objects to JSON format, making it easier to build RESTful APIs. • Advantages: REST controllers are essential for creating APIs that can interact with frontend applications, mobile apps, and other services, making Spring Web highly versatile and suitable for modern architectures.
- 18. Key Features and Annotations 1. Annotations in Spring Web • Annotations simplify the configuration and management of components in Spring Web by reducing XML configuration and allowing configuration directly in code. Some key annotations in Spring Web are: • @RequestMapping • @GetMapping, @PostMapping, @PutMapping, @DeleteMapping • @PathVariable • @RequestParam • @CrossOrigin • @PatchMapping • @RequestBody • @ResponseBody • @Service • @Repository
- 19. • @RequestMapping: • Purpose: Maps HTTP requests to specific controller methods, letting you define what URL patterns are handled by which methods. • Usage: It can be applied at both class and method levels. When applied at the class level, it specifies the base path; when applied at the method level, it further defines specific actions. • Advantages: @RequestMapping provides flexibility for defining URL structures and routing, making it easier to build organized endpoints in the application.
- 20. • @GetMapping, @PostMapping, @PutMapping, @DeleteMapping: • Purpose: These annotations are specific shortcuts for @RequestMapping with HTTP methods (GET, POST, PUT, DELETE), making it clear what type of request the method handles. • Benefits: Enhances code readability by specifying HTTP methods directly, helping developers quickly identify the purpose of each method.
- 21. • @PathVariable: • Purpose: Extracts values from the URI, allowing dynamic URL segments (e.g., /products/{id}). • Advantages: Simplifies the retrieval of dynamic data from URLs, improving the flexibility and user-friendliness of APIs.id}).
- 22. • @RequestParam: • Purpose: Binds query parameters from the URL to method parameters, commonly used for optional values in the query string. • Benefits: Facilitates passing additional optional data, such as search filters, through URLs, making endpoints more versatile.
- 23. • @CrossOrigin • Purpose: Enables Cross-Origin Resource Sharing (CORS) on specific endpoints, allowing requests from different origins. • Usage: Often used in REST APIs to permit front-end applications on different domains to access resources.ing requests from different origins.
- 24. • @PatchMapping • Purpose: Maps HTTP PATCH requests to specific handler methods, used for partially updating resources. • Usage: Allows updating only certain fields of a resource without replacing the entire resource.
- 25. • @RequestBody • Purpose: Binds the body of an HTTP request to a Java object, commonly used in POST and PUT requests for REST APIs. • Usage: Essential for handling JSON or XML input in REST APIs.
- 26. • @ResponseBody • Purpose: Indicates that the return value of a method should be written directly to the HTTP response body, rather than being interpreted as a view name. • Usage: Commonly used in REST controllers for returning JSON data directly.ponse body, rather than being interpreted as a view name.
- 27. • @Service • Purpose: Marks a class as a service layer component in Spring’s architecture. It’s a specialization of the @Component annotation, used specifically for business logic or service classes. • Usage: Indicates that this class contains business logic and acts as a middle layer between controllers and repositories. • Benefits: By marking a class with @Service, it becomes easy for Spring to identify it as a service layer component, supporting better organization and easier application testing. It also enables automatic detection of the class for dependency injection.
- 28. • @Repository • Purpose: Marks a class as a Data Access Object (DAO) or repository layer component. This annotation is also a specialization of @Component but is specifically used for database access layers. • Usage: Typically used in classes that interact directly with the database, such as those using JPA or JDBC. • Benefits: When a class is annotated with @Repository, Spring manages exceptions more effectively by translating database-related exceptions into Spring's data access exceptions. This makes error handling and debugging easier.
- 29. 2. Configuration Options • Spring offers flexible configuration options to cater to different application needs and developer preferences. • XML-based Configuration: • Description: The original method for configuring Spring applications, where beans, dependencies, and other settings are declared in XML files. • Advantages: Allows separation of configuration from code and offers a centralized place to view configurations. • Drawbacks: Can become verbose and harder to maintain in large applications.
- 30. • Java-based Configuration: • Description: Uses Java classes annotated with @Configuration to configure beans and dependencies programmatically. • Advantages: Offers type safety, readability, and is easier to refactor within IDEs. Also, changes in code affect configuration directly, reducing redundancy. • Spring Boot Auto-configuration: • Purpose: Spring Boot automatically configures an application based on its dependencies. For instance, if spring-boot-starter-web is included, it configures an embedded server (like Tomcat) and default MVC setup. • Advantages: Saves setup time, especially for simple or standardized applications, by reducing the need for explicit configurations.
- 31. 3. Dependency Injection (DI) • Explanation: DI is a core feature of the Spring Framework that allows Spring to manage dependencies among components by “injecting” them, promoting loose coupling and enhancing testability. • How It Works: • Dependencies are defined as beans in Spring, and Spring’s IoC container handles the injection of these beans into classes that need them. • @Autowired Annotation: This is a key annotation for DI in Spring. It allows Spring to automatically resolve and inject a dependency bean into the specified field or constructor. • Benefits of DI: • Promotes modular and reusable code by decoupling components. • Facilitates testing, as mock dependencies can easily replace real dependencies. • Simplifies the management of complex dependencies across the application.
- 32. 4. Middleware and Filters • Middleware Concept: • Middleware in web applications intercepts requests and responses, adding functionality like logging, security, and performance monitoring. Spring Web supports middleware through filters and interceptors. • Filters: • Purpose: A filter in Spring processes requests before they reach a servlet. It can modify requests or responses and is often used for cross-cutting concerns like authentication or logging. • Benefits: Filters are suitable for adding logic that applies globally to all requests, such as security or logging.
- 33. • Interceptors: • Purpose: Similar to filters, interceptors provide hooks for pre-processing and post- processing requests at a higher level, just before and after the controller is called. • Usage: Commonly used for handling authentication, measuring execution time, or modifying request headers. • Advantages: Provides a convenient way to add behavior before and after request processing, specifically targeted to controller-level actions.
- 34. DEMO