EclipseLink 使ってみる

ちょっとお仕事の関係で EclipseLink を調べる必要が出てきたので、ひとまず簡単なサンプルを書いてみました。その時のメモです。EclipseLink は JPA、MOXy、DBWS と３つのコンポーネントがあるみたいですが、今回は JPA に関する内容です。

・EclipseLink
http://www.eclipse.org/eclipselink/

■ pom.xml

---

<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>EclipseLinkTest</groupId>
  <artifactId>EclipseLinkTest</artifactId>
  <version>0.0.1</version>
  <dependencies>
	<dependency>
	  <groupId>org.eclipse.persistence</groupId>
	  <artifactId>eclipselink</artifactId>
	  <version>2.5.2</version>
	  <exclusions>
		<exclusion>
			<groupId>org.eclipse.persistence</groupId>
			<artifactId>commonj.sdo</artifactId>
		</exclusion>
	  </exclusions>
	</dependency>
	<dependency>
	  <groupId>postgresql</groupId>
	  <artifactId>postgresql</artifactId>
	  <version>9.0-801.jdbc4</version>
    </dependency>
   </dependencies>
</project>

・EclipseLink/Maven - Eclipsepedia
https://wiki.eclipse.org/EclipseLink/Maven

■ persistence.xml

---

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/persistence persistence_1_0.xsd"
        version="1.0">
  <persistence-unit name="eclipselinktest" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
      <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver"/>
      <property name="javax.persistence.jdbc.url" value="jdbc:postgresql://127.0.0.1/testdb"/>
      <property name="javax.persistence.jdbc.user" value="postgres"/>
      <property name="javax.persistence.jdbc.password" value="postgres"/>
    </properties>
  </persistence-unit>
</persistence>

persistence.xml は META-INF 配下におく。

■ t1.java

---

エンティティクラスです。

package test.entity;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class T1 {
	@Id
	private int id;
	private String name;

	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;
	}

}

■ EMFactory.java

---

EntityManagerFactory の生成クラスです。

package test.factory;

import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class EMFactory {

	public static EntityManagerFactory getEMFactory() {
		return Persistence.createEntityManagerFactory("eclipselinktest");
	}
}

■ T1Access.java

---

EntityManager API を使ったクラスです。今回のサンプルでは find / persist / remove / CriteriaQuery で全件検索をやってます。

package test.access;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;

import test.entity.T1;

public class T1Access {
	public T1 find(EntityManager em, int id) {
		return (T1) em.find(T1.class, id);
	}

	public void persist(EntityManager em, T1 t) {
		em.persist(t);
	}

	public void remove(EntityManager em, T1 t) {
		em.remove(t);
	}

	public List<T1> findAll(EntityManager em) {
		CriteriaBuilder cb = em.getCriteriaBuilder();
		CriteriaQuery<T1> cq = cb.createQuery(T1.class);
		CriteriaQuery<T1> select = cq.select(cq.from(T1.class));
		return em.createQuery(select).getResultList();

	}
}

■ Main.java

---

package test.access;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;

import test.entity.T1;
import test.factory.EMFactory;

public class Main {
	public static void main(String[] args) {
		EntityManagerFactory emf = EMFactory.getEMFactory();
		EntityManager em = emf.createEntityManager();
		EntityTransaction et = em.getTransaction();

		T1Access instance = new T1Access();
				
		et.begin();
		T1 t1 = new T1();
		t1.setId(1);
		t1.setName("hoge");
		T1 t2 = new T1();
		t2.setId(2);
		t2.setName("uga");
		T1 t3 = new T1();
		t3.setId(3);
		t3.setName("oro");
		instance.persist(em, t1);
		instance.persist(em, t2);
		instance.persist(em, t3);
		et.commit();
		
		System.out.println("----- find -----");
		T1 res = instance.find(em, 1);
		System.out.println(res.getId() + ":" + res.getName());
		
		System.out.println("----- findAll -----");
		for(T1 t : instance.findAll(em)) {
			System.out.println(t.getId() + ":" + t.getName());
		}
		
		et.begin();
		instance.remove(em, t2);
		et.commit();
		
		System.out.println("----- findAll(after remove) -----");
		for(T1 t : instance.findAll(em)) {
			System.out.println(t.getId() + ":" + t.getName());
		}
	}
}

※ 実行結果

----- find -----
1:hoge
----- findAll -----
3:oro
2:uga
1:hoge
----- findAll(after remove) -----
3:oro
1:hoge

駆け足でしたが以上です。

・EclipseLink/Examples/JPA - Eclipsepedia
http://wiki.eclipse.org/EclipseLink/Examples/JPA

[ 環境情報 ]
Windows 7 SP1
Java SE 8 Update 74
EclipseLink 2.5.2
PostgreSQL 9.0.4