Using JPA + Eclipselink to manipulate the PostgreSQL database

First, make sure that you have PostgreSQL installed. You can refer to my this article PostgreSQL literacy tutorial.

Use Eclipse to create a new JPA project:

Platform chooses Eclipselink as one of the JPA provider.

The automatically generated project in eclipse looks like this:

Overwrite the autogenerated XML with the contents of the following XML:

<?xml version= "1.0" encoding= "UTF-8"? ><persistence version= "2.0" 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 http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd "> <persistence-unit name=" JERRYJPA "transaction-type=" resource_local "> <provider>org.eclipse.persistence.jpa.persistenceprovider& Lt;/provider> <class>jpatest. person</class> <properties> <property name= "eclipselink.ddl-generation" value= "Create-tab Les "/> <property name=" Javax.persistence.jdbc.url "value=" Jdbc:postgresql://localhost:5432/postgres "/&gt                     ; <property name= "Javax.persistence.jdbc.driver" value= "Org.postgresql.Driver"/> <property name= "javax . Persistence.jdbc.user "value=" Postgres "/> <property name=" Javax.persistence.jdbc.password "value="Test_password"/> </properties> </persistence-unit></persistence> 

Create a new Java class:

package jpatest;import javax.persistence.Basic;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.NamedQuery;import javax.persistence.Table;@Entity@Table(name = "T_PERSON")@NamedQuery(name = "AllPersons", query = "select p from Person p")public class Person {    @Id    @GeneratedValue    private long id;    @Basic    private String firstName;    @Basic    private String lastName;    public long getId() {        return id;    }    public void setId(long newId) {        this.id = newId;    }    public String getFirstName() {        return this.firstName;    }    public void setFirstName(String newFirstName) {        this.firstName = newFirstName;    }    public String getLastName() {        return this.lastName;    }    public void setLastName(String newLastName) {        this.lastName = newLastName;    }}

Now you can write the test program:

package jpatest;import javax.persistence.EntityManager;import javax.persistence.EntityManagerFactory;import javax.persistence.EntityTransaction;import javax.persistence.Persistence;public class Test {public static void main(String[] args) {        String persistenceUnitName = "jerryjpa";          EntityManagerFactory factory = Persistence.createEntityManagerFactory(persistenceUnitName);          EntityManager entityManager = factory.createEntityManager();          EntityTransaction transaction = entityManager.getTransaction();          transaction.begin();          Person user = new Person();          user.setFirstName("Jerry_SAP");        user.setLastName("Wang");        entityManager.persist(user);          transaction.commit();          entityManager.close();          factory.close();          System.out.println("done");    }}

After successful execution, you can see the records in the test Java program that are inserted into the database with JPA in the admin UI of PostgreSQL:

The complete source code for this article and the required library files can be found on my github.

• Eclipselink-2.5.1.jar

• Javax.persistence-2.1.0.jar

• Postgresql-42.1.1.jar

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Using JPA + Eclipselink to manipulate the PostgreSQL database