LearningSpringBoot

week 0:

• basic java ✅
• mini practice: ✅ create a simpe console-based task manger application in java. the purpose of this application is to allow users to add, view and delete tasks from a list.

key features: add task: users can input a task description, which will be stored

view tasks: users can view all their added tasks

delete task: users can delete a task by specifying its index

exit: users can exit the application gracefully

• database sql what is database? -> collection of data stored in a format that can easily be accessed

  we use DMBS have 2: relational (each table store data a specific type of object and we use sql) and no relational (no table or relationship between table and dont understand sql)

  • create a database

week 1:

• intro to spring boot:

  • controller classs = responsible for handling incoming HTTP request and give back response example, take request from web or mobile app and return json

  • @RestController = combine 2 things (@Controller: mark which class is controller + @ResponseBody: the return value should be written directly in HTTP usually as json)

  • So, when you use @RestController, you don't need to annotate each method with @ResponseBody; it's applied automatically.

  • @RequestMapping: map HTTP requests to handler methods of MVC and REST controllers can be applied at both the class and method levels Flexibility: You can specify the HTTP method (GET, POST, etc.), request parameters, headers, and more. example, @RequestMapping("/api/products") --> from localhost:8080 to localhost:8080/api/products public class ProductController { // Methods to handle requests }

  • @GetMapping = is a shortcut for @RequestMapping(method = RequestMethod.GET) used to handle HTTP GET requests @GetMapping("/{id}") --> it mean: /api/products/{id} and return returns a Product object public Product getProduct(@PathVariable Long id) { return productService.getProductById(id); }

    • Service Lyaer = business logic of the application. while the controller manage HTTP request and response, the repo layer handle data access, it coordinate the application operation ensure that business rules are applied consistently

  • what is spring boot:

  • setting up spring boot with spring initializr

  • application structure (main class, annotations: @SpringBootApplication, @Component)

  • properties config (application.properties)

  • dependency injection: @Component, @Service, @Autowired

  • exercise: build a simple "Hello world" REST app

  • mini project: create a greeting REST API with custom message from application.properties

• commandlinerunner = help run a specific piece of code when springboot app start, with the help of run method that we need to override and implement ourself

• @Data = do not need to write getter and setter it automate

• @AllArgs... = no need to write constructor