DZone
Microservices Zone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
  • Refcardz
  • Trend Reports
  • Webinars
  • Zones
  • |
    • Agile
    • AI
    • Big Data
    • Cloud
    • Database
    • DevOps
    • Integration
    • IoT
    • Java
    • Microservices
    • Open Source
    • Performance
    • Security
    • Web Dev
DZone > Microservices Zone > Microservice: Creating JPA Application Using Jakarta Persistence API in Payara Micro

Microservice: Creating JPA Application Using Jakarta Persistence API in Payara Micro

In this blog, we will discuss how your Java microservice application can connect to and interact with a relational database through the Jakarta Persistence API.

BUHAKE SINDI user avatar by
BUHAKE SINDI
CORE ·
Feb. 16, 22 · Microservices Zone · Tutorial
Like (4)
Save
Tweet
4.09K Views

Join the DZone community and get the full member experience.

Join For Free

In this blog, we will discuss how your Java microservice application can connect to and interact with a relational database through the Jakarta Persistence API (the latest version at the time of writing is version 3.0). You can configure a data source and a JDBC driver so an application that is running on your Payara Microserver can connect with a relational database.

Before We Begin:

In this tutorial, we will configure this application with the following components in mind:

  • The microservice application will be a Mavenized Java application.
  • We will use MySQL DB Server as a relational database.
  • The JDBC data source will be a transactional data source (XADataSource).

JDBC Driver Library Configuration With Maven

You need a JDBC driver to connect your Java application with a relational database. The driver is usually provided by the database vendor. Fortunately, most database vendors have released their JDBC drivers to a Maven repository.

If you use Maven to build your application, you can add your JDBC driver by adding code that is similar to the following example to your pom.xml file.

XML
 
    <dependencyManagement>
    	<dependencies>
    		<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    			<version>8.0.19</version>
    		</dependency>
    	</dependencies>
    </dependencyManagement>
    
    <dependencies>
    	<dependency>
    		<groupId>mysql</groupId>
    		<artifactId>mysql-connector-java</artifactId>
    	</dependency>
    </dependencies>


With Maven, the JDBC driver file will be copied to the WEB-INF/lib folder of your application WAR file during the package build phase.

Configuring a Database Datasource

In the Payara Blog, a data source is configured inside the web.xml file. In this example, there is another alternative for creating a data source configuration. The example below demonstrates a basic data source configuration pattern  for the payara-resource.xml file inside the src/main/java/webapp/WEB-INF folder:

XML
 
    <!DOCTYPE resources  PUBLIC  "-//Payara.fish//DTD Payara Server 4 Resource Definitions//EN"  "https://raw.githubusercontent.com/payara/Payara-Community-Documentation/master/docs/modules/ROOT/pages/schemas/payara-resources_1_6.dtd">
    <resources>
        <jdbc-resource pool-name="MyAppDS"
                       jndi-name="java:app/jdbc/MyApp"
                       enable="true"/>
        <jdbc-connection-pool name="MySQLPool"
                              res-type="javax.sql.XADataSource"
                              datasource-classname="com.mysql.cj.jdbc.MysqlXADataSource">
            <property name="url" value="jdbc:h2:mem:hibernateExample"/>
<property name="User" value="testUser"></property>
            <property name="Password" value="testPassword"></property>
            <property name="DatabaseName" value="myapp_db"></property>
            <property name="ServerName" value="localhost"></property>
            <property name="PortNumber" value="3306"></property>
        </jdbc-connection-pool>
    </resources>


Application Configuration for Relational Database Connections

To use a data source that is configured in your payara-resource.xml file, you can either inject the data source or specify a lookup in your application code. The following examples assume that a jndi-name value of java:app/jdbc/MyApp is specified as the jdbc-resource element attribute in the payara-resource.xml file.

Java
 
@Resource(name= "java:app/jdbc/MyApp") 
DataSource myDB;


Injecting JPA EntityManager Into Your Application

Once your data source is configured in your payara-resource.xml file, we need to register your data source inside the persistence.xml in your src/main/resources/META-INF/persistence.xml file. The jta-data-source is and matches the jndi-name of the data source as specified in the payara-resource.xml.

XML
 
    <?xml version="1.0" encoding="UTF-8"?>
    <persistence version="2.1"
    	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_1.xsd ">
    	<persistence-unit name="MyAppPU" transaction-type="JTA">
    		<jta-data-source>java:app/jdbc/MyApp</jta-data-source>
    		<shared-cache-mode>ENABLE_SELECTIVE</shared-cache-mode>
    		<properties>
    			<!-- JBoss Wildfly's Hibernate 4 specific JPA properties -->
    			<property name="hibernate.cache.use_second_level_cache" value="true" />
    			<property name="hibernate.hbm2ddl.auto" value="validate" /><!-- NEVER: update -->
            	<property name="hibernate.show_sql" value="false" />
            	<property name="hibernate.format_sql" value="false"/>
    			<property name="hibernate.use_sql_comments" value="false" />
    			<property name="hibernate.enable_lazy_load_no_trans" value="true"/>
    			<!--  For Performance monitoring on Hibernate -->
    			<property name="hibernate.generate_statistics" value="false"/>
    			<property name="hibernate.cache.use_structured_entries" value="false"/>
    			
    			<!-- TomEE PluME 1.7.2 and higher with EclipseLink  -->
    			<property name="eclipselink.logging.logger" value="JavaLogger" />
    		</properties>
    	</persistence-unit>
    </persistence>


You can inject your jakarta.persistence.EntityManager in your Java application code by specifying your persistence unit MyAppPU in your PersistenceContext annotation:

Java
 
@PersistenceContext(unitName="MyAppPU")
private EntityManager entityManager;


With that, you can get your Java microservice application to connect and interact with a relational database through the Jakarta Persistence API!

application API microservice Persistence (computer science) Relational database Java Database Connectivity Data (computing)

Opinions expressed by DZone contributors are their own.

Popular on DZone

  • 10 Programming Habits a Web Developer Should Embrace
  • How Low Code Demands More Creativity From Developers
  • SSH Tutorial: Nice and Easy [Video]
  • My Sentiments, Erm… Not Exactly

Comments

Microservices Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • MVB Program
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 600 Park Offices Drive
  • Suite 300
  • Durham, NC 27709
  • support@dzone.com
  • +1 (919) 678-0300

Let's be friends:

DZone.com is powered by 

AnswerHub logo