Use Spring Data JPA with Azure Database for PostgreSQL

This tutorial demonstrates how to store data in Azure Database for PostgreSQL using Spring Data JPA.

The Java Persistence API (JPA) is the standard Java API for object-relational mapping.

In this tutorial, we include two authentication methods: Microsoft Entra authentication and PostgreSQL authentication. The Passwordless tab shows the Microsoft Entra authentication and the Password tab shows the PostgreSQL authentication.

Microsoft Entra authentication is a mechanism for connecting to Azure Database for PostgreSQL using identities defined in Microsoft Entra ID. With Microsoft Entra authentication, you can manage database user identities and other Microsoft services in a central location, which simplifies permission management.

PostgreSQL authentication uses accounts stored in PostgreSQL. If you choose to use passwords as credentials for the accounts, these credentials will be stored in the user table. Because these passwords are stored in PostgreSQL, you need to manage the rotation of the passwords by yourself.

Prerequisites

• An Azure subscription - create one for free.

• Java Development Kit (JDK), version 8 or higher.

• Apache Maven.

• Azure CLI.

• PostgreSQL command line client.

• If you don't have a Spring Boot application, create a Maven project with the Spring Initializr. Be sure to select Maven Project and, under Dependencies, add the Spring Web, Spring Data JDBC, and PostgreSQL Driver dependencies, and then select Java version 8 or higher.

cat << EOF > create_ad_user.sql
select * from pgaadauth_create_principal('<your_postgresql_ad_non_admin_username>', false, false);
EOF

psql "host=postgresqlflexibletest.postgres.database.azure.com user=<your_postgresql_ad_admin_username> dbname=postgres port=5432 password=$(az account get-access-token --resource-type oss-rdbms --output tsv --query accessToken) sslmode=require" < create_ad_user.sql

cat << EOF > create_user.sql
CREATE ROLE "<your_postgresql_non_admin_username>" WITH LOGIN PASSWORD '<your_postgresql_non_admin_password>';
GRANT ALL PRIVILEGES ON DATABASE demo TO "<your_postgresql_non_admin_username>";
EOF

psql "host=postgresqlflexibletest.postgres.database.azure.com user=<your_postgresql_admin_username> dbname=demo port=5432 password=<your_postgresql_admin_password> sslmode=require" < create_user.sql

cat << EOF > create_ad_user.sql
SET aad_validate_oids_in_tenant = off;
CREATE ROLE "<your_postgresql_ad_non_admin_username>" WITH LOGIN IN ROLE azure_ad_user;
GRANT ALL PRIVILEGES ON DATABASE demo TO "<your_postgresql_ad_non_admin_username>";
EOF

psql "host=postgresqlsingletest.postgres.database.azure.com user=<your_postgresql_ad_admin_username>@postgresqlsingletest dbname=postgres port=5432 password=$(az account get-access-token --resource-type oss-rdbms --output tsv --query accessToken) sslmode=require" < create_ad_user.sql

cat << EOF > create_user.sql
CREATE ROLE "<your_postgresql_non_admin_username>" WITH LOGIN PASSWORD '<your_postgresql_non_admin_password>';
GRANT ALL PRIVILEGES ON DATABASE demo TO "<your_postgresql_non_admin_username>";
EOF

psql "host=postgresqlsingletest.postgres.database.azure.com user=<your_postgresql_admin_username>@postgresqlsingletest dbname=demo port=5432 password=<your_postgresql_admin_password> sslmode=require" < create_user.sql

2. Create a new Todo Java class. This class is a domain model mapped onto the todo table that will be created automatically by JPA. The following code ignores the getters and setters methods.

   package com.example.demo;
   
   import javax.persistence.Entity;
   import javax.persistence.GeneratedValue;
   import javax.persistence.Id;
   
   @Entity
   public class Todo {
   
       public Todo() {
       }
   
       public Todo(String description, String details, boolean done) {
           this.description = description;
           this.details = details;
           this.done = done;
       }
   
       @Id
       @GeneratedValue
       private Long id;
   
       private String description;
   
       private String details;
   
       private boolean done;
   
   }
   

3. Edit the startup class file to show the following content.

   import org.springframework.boot.SpringApplication;
   import org.springframework.boot.autoconfigure.SpringBootApplication;
   import org.springframework.boot.context.event.ApplicationReadyEvent;
   import org.springframework.context.ApplicationListener;
   import org.springframework.context.annotation.Bean;
   import org.springframework.data.jpa.repository.JpaRepository;
   
   import java.util.stream.Collectors;
   import java.util.stream.Stream;
   
   @SpringBootApplication
   public class DemoApplication {
   
       public static void main(String[] args) {
           SpringApplication.run(DemoApplication.class, args);
       }
   
       @Bean
       ApplicationListener<ApplicationReadyEvent> basicsApplicationListener(TodoRepository repository) {
           return event->repository
               .saveAll(Stream.of("A", "B", "C").map(name->new Todo("configuration", "congratulations, you have set up correctly!", true)).collect(Collectors.toList()))
               .forEach(System.out::println);
       }
   
   }
   
   interface TodoRepository extends JpaRepository<Todo, Long> {
   
   }
   

   Tip

   In this tutorial, there are no authentication operations in the configurations or the code. However, connecting to Azure services requires authentication. To complete the authentication, you need to use Azure Identity. Spring Cloud Azure uses DefaultAzureCredential, which the Azure Identity library provides to help you get credentials without any code changes.

   DefaultAzureCredential supports multiple authentication methods and determines which method to use at runtime. This approach enables your app to use different authentication methods in different environments (such as local and production environments) without implementing environment-specific code. For more information, see DefaultAzureCredential.

   To complete the authentication in local development environments, you can use Azure CLI, Visual Studio Code, PowerShell, or other methods. For more information, see Azure authentication in Java development environments. To complete the authentication in Azure hosting environments, we recommend using user-assigned managed identity. For more information, see What are managed identities for Azure resources?

4. Start the application. You'll see logs similar to the following example:

   2023-02-01 10:29:19.763 DEBUG 4392 --- [main] org.hibernate.SQL : insert into todo (description, details, done, id) values (?, ?, ?, ?)
   com.example.demo.Todo@1f
   

Deploy to Azure Spring Apps

Now that you have the Spring Boot application running locally, it's time to move it to production. Azure Spring Apps makes it easy to deploy Spring Boot applications to Azure without any code changes. The service manages the infrastructure of Spring applications so developers can focus on their code. Azure Spring Apps provides lifecycle management using comprehensive monitoring and diagnostics, configuration management, service discovery, CI/CD integration, blue-green deployments, and more. To deploy your application to Azure Spring Apps, see Deploy your first application to Azure Spring Apps.

Next steps