JPA 시작하기

<?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>jpa-basic</groupId>
    <artifactId>ex1-hello-jpa</artifactId>
    <version>1.0.0</version>

    <dependencies>
<!-- JPA 하이버네이트 --><dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.3.10.Final</version>
        </dependency>
<!-- H2 데이터베이스 --><dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.4.200</version>
        </dependency>

        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.0</version>
        </dependency>
    </dependencies>

    <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
    </properties>

</project>

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.2"
             xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">
    <persistence-unit name="hello">
        <properties>
<!-- 필수 속성 --><property name="javax.persistence.jdbc.driver" value="org.h2.Driver"/>
            <property name="javax.persistence.jdbc.user" value="sa"/>
            <property name="javax.persistence.jdbc.password" value=""/>
            <property name="javax.persistence.jdbc.url" value="jdbc:h2:tcp://localhost/~/test"/>
            <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>

<!-- 옵션 --><property name="hibernate.show_sql" value="true"/><!--쿼리가 로그에 보인다. --><property name="hibernate.format_sql" value="true"/><!--쿼리가 로그 정렬되서 보이게 해준다. --><property name="hibernate.use_sql_comments" value="true"/><!--쿼리가 왜 나오는지 알려준다. --><!--<property name="hibernate.hbm2ddl.auto" value="create" />--></properties>
    </persistence-unit>
</persistence>

package helloJpa;

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

@Entity
public class Member {

    @Id
    private Long id;
    private String name;

    public void setId(Long id) {
        this.id = id;
    }

    public Long getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

package helloJpa;

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

public class JpaMain {

    public static void main(String[] args) {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("hello");// 애플리케이션 에서 한개만 만들어 져야된다.

        EntityManager em = emf.createEntityManager();//하나의 단위를 만들때마다 만들어 줘야된다.

        EntityTransaction tx = em.getTransaction();
        tx.begin();

        try {
            Member member = new Member();
            member.setId(1L);
            member.setName("HelloA");
            em.persist(member);
            tx.commit();
        } catch (Exception e) {
            tx.rollback();
        } finally {
            em.close();
        }
        emf.close();
    }
}

package helloJpa;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
import java.util.List;

public class JpaMain {

    public static void main(String[] args) {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("hello");// 애플리케이션 에서 한개만 만들어 져야된다.
                EntityManager em = emf.createEntityManager();//하나의 단위를 만들때마다 만들어 줘야된다.
                EntityTransaction tx = em.getTransaction();
        tx.begin();

        try {
// Member findMember = em.find(Member.class, 1L);// findMember.setName("HelloJpa");// JPQL 사용방법List<Member> resultList = em.createQuery("select m from Member as m", Member.class).
                    getResultList();

            for (Member member : resultList) {
                System.out.println("member.name = " + member.getName());
            }

            tx.commit();
        } catch (Exception e) {
            tx.rollback();
        } finally {
            em.close();
        }
        emf.close();
    }
}