Initializing Data With Spring Boot

src/main/java/guru/springframework/spring6webapp/bootstrap/BootstrapData.java

@@ -0,0 +1,62 @@
+package guru.springframework.spring6webapp.bootstrap;
+
+import guru.springframework.spring6webapp.domain.Author;
+import guru.springframework.spring6webapp.domain.Book;
+import guru.springframework.spring6webapp.repositories.IAuthorRepositroy;
+import guru.springframework.spring6webapp.repositories.IBookRepository;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.stereotype.Component;
+
+@Component // This annotation indicates that this class is a Spring component and will be automatically detected by Spring's component scanning
+public class BootstrapData implements CommandLineRunner {
+
+    private final IAuthorRepositroy iAuthorRepositroy;
+    private final IBookRepository iBookRepository;
+
+    public BootstrapData(IAuthorRepositroy iAuthorRepositroy, IBookRepository iBookRepository) {
+        this.iAuthorRepositroy = iAuthorRepositroy;
+        this.iBookRepository = iBookRepository;
+    }
+
+
+    @Override
+    public void run(String... args) throws Exception {
+        Author author1 = new Author();
+        author1.setFirstName("Nabil");
+        author1.setLastName("Boutachrafine");
+
+        Book book1 = new Book();
+        book1.setTitle("Spring Framework 6");
+        book1.setIsbn("1234567890");
+
+        Author authorSaved1 = iAuthorRepositroy.save(author1);
+        Book bookSaved1 = iBookRepository.save(book1);
+
+        Author author2 = new  Author();
+        author2.setFirstName("Tawfiq");
+        author2.setLastName("Boutachrafine");
+
+        Book book2 = new Book();
+        book2.setTitle("Spring Boot 3");
+        book2.setIsbn("0987654321");
+
+        Author authorSaved2 = iAuthorRepositroy.save(author2);
+        Book bookSaved2 = iBookRepository.save(book2);
+
+        authorSaved1.getBooks().add(bookSaved1);
+        authorSaved2.getBooks().add(bookSaved2);
+
+        iAuthorRepositroy.save(authorSaved1);
+        iAuthorRepositroy.save(authorSaved2);
+
+        System.out.println("Bootstrap Data Loaded");
+        System.out.println("Number of Authors: " + iAuthorRepositroy.count());
+        System.out.println("Number of Books: " + iBookRepository.count());
+    }
+}
+
+
+
+
+
+

src/main/java/guru/springframework/spring6webapp/domain/Author.java

@@ -2,6 +2,7 @@
 
 import jakarta.persistence.*;
 
+import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
 
@@ -14,7 +15,7 @@ public class Author {
     private String lastName;
 
     @ManyToMany(mappedBy = "authors") // this annotation indicates a many-to-many relationship with the Book entity
-    private Set<Book> books;
+    private Set<Book> books = new HashSet<>();
 
     public Long getIdAuthor() {
         return idAuthor;

src/main/java/guru/springframework/spring6webapp/domain/Book.java

@@ -2,6 +2,7 @@
 
 import jakarta.persistence.*;
 
+import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
 
@@ -16,7 +17,7 @@ public class Book {
     @ManyToMany
     @JoinTable(name ="author_book", joinColumns = @JoinColumn(name = "book_id"),
     inverseJoinColumns = @JoinColumn(name = "author_id")) // This annotation defines the join table for the many-to-many relationship
-    private Set<Author> authors;
+    private Set<Author> authors = new HashSet<>();
 
     public Long getIdBook() {
         return idBook;

src/main/resources/application.properties

@@ -1 +1,2 @@
-
+server.port=9090
+//spring.jpa.open-in-view=false