springframeworkguru#21 - Configuring Spring MVC Controllers (for Book)

src/main/java/guru/springframework/spring5webapp/controllers/BookController.java

@@ -0,0 +1,41 @@
+package guru.springframework.spring5webapp.controllers;
+
+import guru.springframework.spring5webapp.repositories.BookRepository;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+/**
+ * Created by Hannes Groeller on 10/24/2022.
+ */
+
+@Controller
+public class BookController {
+
+    // To enhance that model with a list of books, one has to bring in
+    // an instance of the book repository.
+    private final BookRepository bookRepository;
+
+    public BookController(BookRepository bookRepository) {
+        this.bookRepository = bookRepository;
+    }
+
+    // At runtime, when Spring gets a request to the URL /books it is going to
+    // execute the getBooks method, and it's going to provide that method a model,
+    // a model object, and our code is saying for that model we are going to add
+    // the attribute called books, and we're going to get execute book repository
+    // which is going to give us a list of books.
+    // Now this model is going to get returned back to our view layer, and it's
+    // going to have an attribute books and a list of books on that, and then
+    // we'll be able to utilize that value inside our view layer to apply the
+    // necessary view that we're going to be returning back to the client.
+    @RequestMapping("/books")
+    public String getBooks(Model model){
+
+        model.addAttribute("books", bookRepository.findAll());
+
+        // Define the view name.  We will configure it in class #22
+        // (Thymeleaf Templates).
+        return "books";
+    }
+}