Summary
Highlights
The session begins by introducing the concept of user authentication in a Spring Boot application, focusing on implementing Spring Security. The project structure for a 'User Auth Demo' is outlined, including folders for controllers, services, repositories, entities, and configuration. The essential dependencies like 'Starter Web', 'Data JPA', 'MySQL Connector', and 'Security' are identified for inclusion in the 'pom.xml'.
A significant portion of the session is dedicated to explaining Hibernate, an open-source ORM (Object-Relational Mapping) framework for Java. Hibernate simplifies database interactions by mapping Java objects to database tables, reducing the need for manual JDBC code. The 'application.properties' file's role in configuring Hibernate, including 'DDL auto update' for schema management and 'hibernate dialect' for database-specific communication (e.g., MySQL 8 dialect), is detailed.
The practical steps of setting up the Spring Boot project are demonstrated, including creating a new project from 'start.spring.io' with the necessary dependencies. The process of extracting the generated project, importing it into Eclipse, and configuring the 'application.properties' with database details (MySQL database named 'user_auth_DB') is shown. An initial attempt to run the application to facilitate table creation by Hibernate is made.
The session encounters several debugging challenges. Initially, Hibernate fails to create tables due to misconfigurations related to JPA and a 'class not found' error for the MySQL 8 dialect. The dialect line is removed as it's considered outdated. A key revelation is made about Spring Boot's package scanning mechanism: it only scans sub-packages of the main application class. This leads to issues where entities and repositories are not being picked up, preventing table creation. The solution involves moving all packages under a unified base package structure.
The implementation of password encoding using BCrypt is detailed, with the creation of an 'AppConfig' class to define a 'BCryptPasswordEncoder' bean. The 'User' entity is created with 'username', 'password', and 'role' fields. Further debugging focuses on why the application's login screen, automatically generated by Spring Security, isn't accepting credentials. The difficulty in debugging the login method directly and the challenge of matching encrypted passwords with user inputs are discussed. A student successfully demonstrates the login working via Postman using a pre-generated BCrypt password, highlighting the difference in behavior between the UI and direct API calls.
The session concludes by outlining the next steps: implementing user sign-up functionality. Attendees are tasked with a homework assignment to use an AI tool (like ChatGPT) to generate steps for user sign-up with MySQL and Spring Boot, which will then be added to GitHub for further development. The importance of establishing a clear project structure, starting with 'Sign Up and Login' and then moving to a 'Dashboard', is emphasized.