2.1 jpa equals

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

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+package guru.springframework.spring6webapp.bootstrap;
+
+import guru.springframework.spring6webapp.domain.Author;
+import guru.springframework.spring6webapp.domain.Book;
+import guru.springframework.spring6webapp.repositories.AuthorRepository;
+import guru.springframework.spring6webapp.repositories.BookRepository;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.stereotype.Component;
+
+@Component
+public class BootstrapData implements CommandLineRunner {
+
+
+    private final AuthorRepository authorRepository;
+    private final BookRepository bookRepository;
+
+    public BootstrapData(AuthorRepository authorRepository, BookRepository bookRepository) {
+        this.authorRepository = authorRepository;
+        this.bookRepository = bookRepository;
+    }
+
+    @Override
+    public void run(String... args) throws Exception {
+        Author eric = new Author();
+        eric.setFirstName("Eric");
+        eric.setLastName("Evans");
+
+        Book ddd = new Book();
+        ddd.setTitle("Domain Driven Design");
+        ddd.setIsbn("123456");
+
+
+        Author ericSaved = authorRepository.save(eric);
+        Book dddSaved = bookRepository.save(ddd);
+
+        Author rod = new Author();
+        rod.setFirstName("Rod");
+        rod.setLastName("Johnson");
+
+        Book noEJB = new Book();
+        noEJB.setTitle("J2EE Development without EJB");
+        noEJB.setIsbn("54757585");
+
+        Author rodSaved = authorRepository.save(rod);
+        Book noEJBSaved = bookRepository.save(noEJB);
+
+        ericSaved.getBooks().add(dddSaved);
+        rodSaved.getBooks().add(noEJBSaved);
+
+        authorRepository.save(ericSaved);
+        authorRepository.save(rodSaved);
+
+        System.out.println("In Bootstrap");
+        System.out.println("Author Count: " + authorRepository.count());
+        System.out.println("Book Count:" + bookRepository.count());
+
+
+
+    }
+}
+
+
+
+
+
+
+
+

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

@@ -0,0 +1,83 @@
+package guru.springframework.spring6webapp.domain;
+
+import jakarta.persistence.*;
+
+import java.util.HashSet;
+import java.util.Set;
+
+@Entity
+public class Author {
+
+    @Id
+    @GeneratedValue(strategy= GenerationType.AUTO)
+    private long id;
+    private String firstName;
+    private String lastName;
+
+    @ManyToMany(mappedBy = "authors")
+    private Set<Book> books = new HashSet<>();
+
+    public Set<Book> getBooks() {
+        return books;
+    }
+
+    public void setBooks(Set<Book> books) {
+        this.books = books;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+
+    @Override
+    public String toString() {
+        return "Author{" +
+                "id=" + id +
+                ", firstName='" + firstName + '\'' +
+                ", lastName='" + lastName + '\'' +
+                ", books=" + books +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Author author = (Author) o;
+
+        return id == author.id;
+    }
+
+    @Override
+    public int hashCode() {
+        return (int) (id ^ (id >>> 32));
+    }
+}
+
+
+
+
+
+

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

@@ -0,0 +1,85 @@
+package guru.springframework.spring6webapp.domain;
+
+import jakarta.persistence.*;
+
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.Set;
+
+@Entity
+public class Book {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private Long id;
+    private String title;
+    private String isbn;
+
+    @ManyToMany
+    @JoinTable(name = "author_book", joinColumns = @JoinColumn(name = "book_id"),
+        inverseJoinColumns = @JoinColumn(name = "author_id"))
+    private Set<Author> authors = new HashSet<>();
+
+    public Set<Author> getAuthors() {
+        return authors;
+    }
+
+    public void setAuthors(Set<Author> authors) {
+        this.authors = authors;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getIsbn() {
+        return isbn;
+    }
+
+    public void setIsbn(String isbn) {
+        this.isbn = isbn;
+    }
+
+
+    @Override
+    public String toString() {
+        return "Book{" +
+                "id=" + id +
+                ", title='" + title + '\'' +
+                ", isbn='" + isbn + '\'' +
+                ", authors=" + authors +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Book book = (Book) o;
+
+        return Objects.equals(id, book.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return id != null ? id.hashCode() : 0;
+    }
+}
+
+
+
+
+

src/main/java/guru/springframework/spring6webapp/repositories/AuthorRepository.java

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+package guru.springframework.spring6webapp.repositories;
+
+import guru.springframework.spring6webapp.domain.Author;
+import org.springframework.data.repository.CrudRepository;
+
+public interface AuthorRepository extends CrudRepository<Author,Long>{
+}

src/main/java/guru/springframework/spring6webapp/repositories/BookRepository.java

@@ -0,0 +1,7 @@
+package guru.springframework.spring6webapp.repositories;
+
+import guru.springframework.spring6webapp.domain.Book;
+import org.springframework.data.repository.CrudRepository;
+
+public interface BookRepository extends CrudRepository<Book,Long> {
+}