pom.xml
- lombok
- spring-boot-starter-data-jpa
- mysql-connector-java
application.properties
# MySQL connection properties
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.username=username
spring.datasource.password=password
spring.datasource.url=jdbc:mysql://localhost:3306/testspring
# Log JPA queries
# Comment this in production
spring.jpa.show-sql=true
# Drop and create new tables (create, create-drop, validate, update)
# Only for testing purpose - comment this in production
spring.jpa.hibernate.ddl-auto=create-drop
# Hibernate SQL dialect
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
ResApplication.java
public class RestApplication {
public static void main(String[] args) {
SpringApplication.run(RestApplication.class, args);
}
@Bean
public CommandLineRunner mappingDemo(BookRepository bookRepository,
PageRepository pageRepository) {
return args -> {
// create a new book
Book book = new Book("Java 101", "John Doe", "123456");
// save the book
bookRepository.save(book);
pageRepository.save(new Page(65, "Java 8 contents", "Java 8", book));
pageRepository.save(new Page(95, "Concurrency contents", "Concurrency", book));
};
}
}
Book.java
@Entity
@Table(name = "books")
@Getter
@Setter
public class Book implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String title;
private String author;
@Column(unique = true)
private String isbn;
```**```@JsonManagedReference```**```
@OneToMany(mappedBy = "book", fetch = FetchType.LAZY,
cascade = CascadeType.ALL)
private List<Page> pages = new ArrayList<Page>();
public Book() {
}
public Book(String title, String author, String isbn) {
this.title = title;
this.author = author;
this.isbn = isbn;
}
// getters and setters, equals(), toString() .... (omitted for brevity)
@Override
public String toString() {
return "Book{" +
"id=" + id +
", title='" + title + '\'' +
", author='" + author + '\'' +
", isbn='" + isbn + '\'' +
", number of pages=" + pages.size() +
'}';
}
}
Pages.java
@Entity
@Table(name = "pages")
@Setter
@Getter
public class Page implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private int number;
private String content;
private String chapter;
@JsonBackReference
@ManyToOne(fetch = FetchType.LAZY, optional = false)
@JoinColumn(name = "book_id", nullable = false)
private Book book;
public Page() {
}
public Page(int number, String content, String chapter, Book book) {
this.number = number;
this.content = content;
this.chapter = chapter;
this.book = book;
}
// getters and setters, equals(), toString() .... (omitted for brevity)
@Override
public String toString() {
return "Page{" +
"id=" + id +
", number=" + number +
", content='" + content + '\'' +
", chapter='" + chapter + '\'' +
", book=" + book.toString() +
'}';
}
}
BookRepository.java
public interface BookRepository extends CrudRepository<Book, Long> {
Book findByIsbn(String isbn);
}
PageRepository.java
public interface PageRepository extends CrudRepository<Page, Long> {
List<Page> findByBook(Book book, Sort sort);
}
BooksController.java
@RestController
@RequestMapping(value = "/books", produces = MediaType.APPLICATION_JSON_VALUE)
public class BooksController {
private final BookRepository bookRepository;
private final PageRepository pageRepository;
public BooksController(BookRepository bookRepository, PageRepository pageRepository) {
this.bookRepository = bookRepository;
this.pageRepository = pageRepository;
}
@GetMapping(value = "/pages", produces = MediaType.APPLICATION_JSON_VALUE)
@ResponseStatus(HttpStatus.OK)
public List<Page> pages(){
List<Page> result = (List<Page>) pageRepository.findAll();
System.out.println(result);
System.out.println(result.get(0));
return result;
}
@GetMapping("/")
public List<Book> books(){
return (List<Book>)bookRepository.findAll();
}
}
http://localhost:8080/books/
[
{
"id": 1,
"title": "Java 101",
"author": "John Doe",
"isbn": "123456",
"pages": [
{
"id": 1,
"number": 1,
"content": "Introduction contents",
"chapter": "Introduction"
},
{
"id": 2,
"number": 65,
"content": "Java 8 contents",
"chapter": "Java 8"
},
{
"id": 3,
"number": 95,
"content": "Concurrency contents",
"chapter": "Concurrency"
}
]
}
]
http://localhost:8080/books/pages
[
{
"id": 1,
"number": 1,
"content": "Introduction contents",
"chapter": "Introduction"
},
{
"id": 2,
"number": 65,
"content": "Java 8 contents",
"chapter": "Java 8"
},
{
"id": 3,
"number": 95,
"content": "Concurrency contents",
"chapter": "Concurrency"
}
]
