JPA PostgreSQL Spring Service Example

This is a Spring Boot based microservice example backed by PostgreSQL database. This examples shows the following:

• Use spring.datasource properties and Spring Data auto configuration.
• How to use JPA's CrudRepository
• How to insert UUID field in Postgres database and generate UUID index.
• How to convert Java Enum to Postgres Enum type.
• How to use Dozer Java Bean mapper.

PostgreSQL Assumptions

• You have a PostgreSQL database server running on your localhost and in port 5432.
• You have a database named postgres running on the server
• The server has a user named postgres with password postgres.
• If any of the assumptions doesn't hold true, change the spring.datasource properties in the application.yml file.

Create Database Entities

Execute the create-db.sql script under resources directory on your PostgreSQL server either using PostgreSQL administration and management tools, pgAdmin, or from the PostgreSQL interactive terminal program, called psql.

Build

Execute the following command from the parent directory:

mvn clean install

Start the Service

The main entry point jpa-postgres-spring example is com.basaki.example.postgres.boot.BookApplication class. You can start the application from an IDE by starting the BookApplication class.

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 :: Spring Boot ::        (v1.4.1.RELEASE)
...
2017-03-08 21:50:17.987  INFO 62548 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-03-08 21:50:17.992  INFO 62548 --- [           main] c.b.e.p.spring.boot.BookApplication      : Started BookApplication in 7.152 seconds (JVM running for 7.566)

The application starts up at port 8080.

Accessing Swagger

On your browser, navigate to http://localhost:8080/ to view the Swagger.

Click the Show/Hide link to view all the operations exposed by Book API.

POST Example

Once expanded, create a new Book entry by clicking POST and entering the following JSON snippet in the request field and click Try it out!.

Here is the response you get back. Please notice the book title and the author gets captitalized before insertion.

GET Example

To view all books, click GET and entry either title, author, genre or any combination of them and click lick Try it out!. The title and author parameters are case insensitive. Here is the response you get back: