JPA HSQL Many to many

Author: giaunv

jpa-hibernate-examples/jpa-hibernate-many-to-many-hsql/.gitignore

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+.idea
+*.iml
+target
+*.DS_Store
+.mvn
+mvn*

jpa-hibernate-examples/jpa-hibernate-many-to-many-hsql/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.hellokoding</groupId>
+	<artifactId>jpa</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>JPA Many-To-Many Example</name>
+	<description>JPA Many-To-Many Example</description>
+
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.1.4.RELEASE</version>
+	</parent>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<java.version>1.7</java.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-data-jpa</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.hsqldb</groupId>
+			<artifactId>hsqldb</artifactId>
+			<scope>runtime</scope>
+		</dependency>
+	</dependencies>
+	
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+</project>

jpa-hibernate-examples/jpa-hibernate-many-to-many-hsql/src/main/java/com/hellokoding/jpa/Application.java

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+package com.hellokoding.jpa;
+
+import com.hellokoding.jpa.model.Book;
+import com.hellokoding.jpa.model.Publisher;
+import com.hellokoding.jpa.repository.BookRepository;
+import com.hellokoding.jpa.repository.PublisherRepository;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+import javax.transaction.Transactional;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+@SpringBootApplication
+public class Application implements CommandLineRunner {
+    private static final Logger logger = LoggerFactory.getLogger(Application.class);
+
+    @Autowired
+    private BookRepository bookRepository;
+
+    @Autowired
+    private PublisherRepository publisherRepository;
+
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+
+    @Override
+    @Transactional
+    public void run(String... strings) throws Exception {
+        // save a couple of books
+        Publisher publisherA = new Publisher("Publisher A");
+        Publisher publisherB = new Publisher("Publisher B");
+        Publisher publisherC = new Publisher("Publisher C");
+        Book bookA = new Book("Book A", new HashSet<>(Arrays.asList(publisherA, publisherB)));
+        Book bookB = new Book("Book B", new HashSet<>(Arrays.asList(publisherA, publisherC)));
+        bookRepository.saveAll(Arrays.asList(bookA, bookB));
+
+        // fetch all books
+        for(Book book : bookRepository.findAll()) {
+            logger.info(book.toString());
+        }
+
+        // save a couple of publishers
+        Book bookD = new Book("Book D");
+        Book bookE = new Book("Book E");
+        Book bookF = new Book("Book F");
+        Publisher publisherD = new Publisher("Publisher D", new HashSet<Book>(Arrays.asList(bookD, bookE)));
+        Publisher publisherE = new Publisher("Publisher E", new HashSet<Book>(Arrays.asList(bookE, bookF)));
+        publisherRepository.saveAll(Arrays.asList(publisherD, publisherE));
+
+        // fetch all publishers
+        for(Publisher publisher : publisherRepository.findAll()) {
+            logger.info(publisher.toString());
+        }
+    }
+}

jpa-hibernate-examples/jpa-hibernate-many-to-many-hsql/src/main/java/com/hellokoding/jpa/model/Book.java

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+package com.hellokoding.jpa.model;
+
+import javax.persistence.*;
+import java.util.Set;
+
+@Entity
+public class Book{
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private int id;
+
+    private String name;
+
+    @ManyToMany(cascade = CascadeType.ALL)
+    @JoinTable(name = "book_publisher", joinColumns = @JoinColumn(name = "book_id", referencedColumnName = "id"), inverseJoinColumns = @JoinColumn(name = "publisher_id", referencedColumnName = "id"))
+    private Set<Publisher> publishers;
+
+    public Book() {
+
+    }
+
+    public Book(String name) {
+        this.name = name;
+    }
+
+    public Book(String name, Set<Publisher> publishers){
+        this.name = name;
+        this.publishers = publishers;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Set<Publisher> getPublishers() {
+        return publishers;
+    }
+
+    public void setPublishers(Set<Publisher> publishers) {
+        this.publishers = publishers;
+    }
+
+    @Override
+    public String toString() {
+        String result = String.format(
+                "Book [id=%d, name='%s']%n",
+                id, name);
+        if (publishers != null) {
+            for(Publisher publisher : publishers) {
+                result += String.format(
+                        "Publisher[id=%d, name='%s']%n",
+                        publisher.getId(), publisher.getName());
+            }
+        }
+
+        return result;
+    }
+}

jpa-hibernate-examples/jpa-hibernate-many-to-many-hsql/src/main/java/com/hellokoding/jpa/model/Publisher.java

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+package com.hellokoding.jpa.model;
+
+import javax.persistence.*;
+import java.util.Set;
+
+@Entity
+public class Publisher {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private int id;
+
+    private String name;
+
+    @ManyToMany(mappedBy = "publishers")
+    private Set<Book> books;
+
+    public Publisher(){
+
+    }
+
+    public Publisher(String name){
+        this.name = name;
+    }
+
+    public Publisher(String name, Set<Book> books){
+        this.name = name;
+        this.books = books;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Set<Book> getBooks() {
+        return books;
+    }
+
+    public void setBooks(Set<Book> books) {
+        this.books = books;
+    }
+
+    @Override
+    public String toString() {
+        String result = String.format(
+            "Publisher [id=%d, name='%s']%n",
+            id, name);
+        if (books != null) {
+            for(Book book : books) {
+                result += String.format(
+                    "Book[id=%d, name='%s']%n",
+                    book.getId(), book.getName());
+            }
+        }
+
+        return result;
+    }
+}

jpa-hibernate-examples/jpa-hibernate-many-to-many-hsql/src/main/java/com/hellokoding/jpa/repository/BookRepository.java

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+package com.hellokoding.jpa.repository;
+
+import com.hellokoding.jpa.model.Book;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface BookRepository extends JpaRepository<Book, Integer>{
+}

jpa-hibernate-examples/jpa-hibernate-many-to-many-hsql/src/main/java/com/hellokoding/jpa/repository/PublisherRepository.java

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+package com.hellokoding.jpa.repository;
+
+import com.hellokoding.jpa.model.Publisher;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface PublisherRepository extends JpaRepository<Publisher, Long>{
+}

jpa-hibernate-examples/jpa-hibernate-many-to-many-hsql/src/main/resources/application.properties

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+spring.jpa.hibernate.ddl-auto=create-drop
+spring.jpa.show-sql=true