JPA getting started, easy example of JPA, JPA annotation example, JPA with Hibernate

Very basic example of how to implement JPA using hibernate provider for mysql database.

Create one project in Eclipse (say JPABlogTestHibernate) add these jar files.

1. log4j-1.2.15.jar
2. mysql-connector-java-3.1.12-bin.jar
3. persistence-api-1.0.jar
4. slf4j-simple-1.4.2.jar
5. cglib-2.1_3.jar
6. cglib-asm-1.0.jar
7. commons-collections-3.2.jar
8. commons-logging-1.1.jar
9. hibernate-core-3.3.1.GA.jar
10. hibernate-entitymanager-3.3.1.ga.jar
11. javassist-3.3.jar
12. jta-1.0.1B.jar
13. jboss-archive-browsing-5.0.0alpha-200607201-119.jar
14. dom4j-1.6.1.jar
15. slf4j-api-1.4.2.jar
16. hibernate-tools-3.2.0.beta9a.jar
17. hibernate-annotations-3.4.0.GA.jar
18. hibernate-commons-annotations-3.1.0.GA.jar
19. antlr-2.7.7.jar

Create one persistence.xml inside src\META-INF folder.
create one package inside src say com.suman
Add these files

Company.java
TestApplication.java
persistence.xml

log4j.xml inside src folder

Company.java (src\com\suman)

package com.suman;
import javax.annotation.Generated;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Transient;
import org.apache.log4j.Logger;

/**
* @author Binod Suman
*/

@Entity
@Table(name="blogcompany")
public class Company {
@Id
private int id;
@Column(name="cname")
private String name;
private String city;

@Transient
Logger log = Logger.getLogger(Company.class);

public Company(){};

public Company(String name, String city) {
super();
this.name = name;
this.city = city;
}

public Company(int id, String name, String city) {
super();
this.id = id;
this.name = name;
this.city = city;
}

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 String getCity() {
return city;
}


public void setCity(String city) {
this.city = city;
}

}


TestApplication.java (src\com\suman)
package com.suman;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import org.apache.log4j.Logger;

/**
* @author Binod Suman
*/

public class TestApplication {
Logger log = Logger.getLogger(TestApplication.class);
public static void main(String[] args) {
TestApplication test = new TestApplication();
test.saveCompany();
}

public void saveCompany(){
log.info("Company data is going to save");
EntityManagerFactory emf;
emf = Persistence.createEntityManagerFactory("jpablogPUnit");
EntityManager entityManager = (EntityManager) emf.createEntityManager();
entityManager.getTransaction().begin();
Company company = new Company(110,"TecnoTree","Bangalore");
entityManager.persist(company);
entityManager.getTransaction().commit();
log.info("Company data has been saved");
}
}


Create database table blogcompany inside the sumandb database.
CREATE TABLE blogcompany (
id int(11) NOT NULL,
cname varchar(100) default NULL,
city varchar(100) default NULL,
PRIMARY KEY (id)
)

Now you can run the TestApplication.java and see the log on console
One record has been inserted into blogcompany table.

That's easy ............ :)

If you have question and doubt then please give your comment or if you have any feedback.

Thanks .......... :)