Spring Boot Primer An introductory book to not regret [Hands-On] Learn spring boot 2.4 from the basics~ Java, Spring Data… (Tatsuya Tamura) (Z-Library)

# Spring Boot Primer: An Introductory Book to Not Regret [Hands-On] ## 【One-Line Pitch】 A practical, hands-on introduction to Spring Boot 2.4 for beginners who want to build web applications without getting lost in theory—covering everything from environment setup to database access, security, and REST APIs through working examples. ## 【Book Arc】 - **Opening (~0%–10%)**: Starts with Spring framework fundamentals—what a framework is, IoC concepts, and why Spring Boot simplifies development. Walks through setting up the development environment with Eclipse/STS and Lombok installation, then creates a first "Hello World" project to demonstrate the basic structure. - **Early (~10%–29%)**: Builds a complete sample application step-by-step: displaying HTML with Thymeleaf, passing values between screens, and retrieving data from an H2 in-memory database using JDBC. Introduces the Controller-Service-Repository pattern and Lombok's @Data annotation to reduce boilerplate. - **Early–Middle (~29%–42%)**: Transitions to a full-scale web application project with login functionality. Deep-dives into Dependency Injection (DI)—what it is, how to implement it with @Autowired, bean registration, scopes, and common pitfalls like singleton state issues and DI from non-bean classes. - **Middle (~42%–48%)**: Covers screen creation with Bootstrap via WebJars, message properties for centralized text management, multilingualization, and form binding with @ModelAttribute. Introduces validation annotations like @NumberFormat for input checking. - **Late (~48%–100%)**: Continues with screen layout implementation, MyBatis for database operations (CRUD, dynamic SQL, table joins, transactions), AOP for cross-cutting concerns like logging, error handling strategies, Spring Security for authentication/authorization, REST API implementation, and Spring Data JPA as an alternative persistence approach. ## 【Key Takeaways】 - **Frameworks save development effort through IoC** (Early): Instead of writing all program logic, you create only the necessary parts and the framework calls your code—this inversion of control is the foundation of Spring's design philosophy. - **Spring Boot's auto-configuration and starter dependencies simplify setup** (Early): The main method in the Application class starts everything, and the project structure (src/main/java, resources, templates) is standardized for rapid development. - **The Controller-Service-Repository pattern organizes web applications** (Early): Controllers handle HTTP requests, services contain business logic, and repositories manage database operations—this separation keeps code maintainable and testable. - **Lombok eliminates boilerplate code** (Early): The @Data annotation automatically generates getters, setters, toString, hashCode, and equals methods, saving significant time when working with data classes. - **Dependency Injection manages object lifecycles** (Middle): Spring creates and destroys instances automatically, with scopes (singleton, request, etc.) controlling instance lifetime—but singleton scope requires stateless design to avoid concurrency issues. - **DI has practical pitfalls to avoid** (Middle): Services default to singleton scope, so mutable state fields can cause unexpected behavior; also, @Autowired only works on Spring-managed beans, not plain classes. - **Centralized message management enables multilingual applications** (Middle): Moving fixed strings to property files allows batch changes and internationalization—essential for applications used across different languages. - **Multiple persistence options exist for different needs** (Late): MyBatis offers fine-grained SQL control with dynamic queries and table joins, while Spring Data JPA provides automatic CRUD operations—the choice depends on project requirements. ## 【Reading Tips】 - **Skim the environment setup chapters** (~0%–10%) if you already have Eclipse/STS configured—the key takeaway is the project structure and how to run a Spring Boot application, not the IDE installation details. - **Deep-read the Hello World chapter** (~10%–29%) as it establishes the fundamental pattern: controller → service → repository → database, with Thymeleaf for view rendering. This pattern repeats throughout the book. - **Pay special attention to the DI pitfalls section** (Middle ~39%–42%)—these are common interview questions and real-world bugs that beginners frequently encounter. - **The later chapters (MyBatis, AOP, Security, REST, JPA)** are more advanced; skim the overview sections first, then focus on the implementation examples that match your project needs. - **Follow along with the code samples**—the book is hands-on, and the value comes from actually building the sample applications rather than just reading about them. ## 【Coverage Limits】 This guide covers the book's progression from Spring Boot basics through database access, DI, validation, and advanced topics like security and REST. The excerpts do not cover the final chapters' detailed code for Spring Security configuration, REST implementation specifics, or Spring Data JPA advanced features in depth. ##