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:

<?xmlVersion= "1.0" encoding= "UTF-8"?><persistenceversion="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-unitname="JERRYJPA"transaction-type="Resource_local">        <provider>Org.eclipse.persistence.jpa.PersistenceProvider</provider>        <class>Jpatest. Person</class>        <properties>            <propertyname="Eclipselink.ddl-generation"value="Create-tables" />            <propertyname="Javax.persistence.jdbc.url"value="Jdbc:postgresql://localhost:5432/postgres"/>                     <propertyname="Javax.persistence.jdbc.driver"value="Org.postgresql.Driver"/>              <propertyname="Javax.persistence.jdbc.user"value="Postgres"/>              <propertyname="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 the person P") Public classperson {@Id    @GeneratedValue    Private LongId@Basic    PrivateString FirstName;@Basic    PrivateString LastName; Public Long getId() {returnId } Public void setId(LongNEWID) { This.ID= NewId; } PublicStringGetfirstname() {return  This.FirstName; } Public void Setfirstname(String newfirstname) { This.FirstName= Newfirstname; } PublicStringGetlastname() {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 classTest { 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