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Connect a Spring Data YugabyteDB application

The example on this page shows how you can connect a Spring application to Yugabyte Cloud, using a version of the Spring PetClinic sample application that has been updated with a domain and persistence layer built with Spring Data YugabyteDB.

In addition to using Spring Data YugabyteDB, the application uses the following:

Flyway to manage the database schema and initial data loading.
SpringFox to deliver Swagger/OpenAPI docs.

The repository for the application is at https://github.com/yugabyte/petclinic-spring-data-yugabytedb. Instructions for connecting this application to YugabyteDB are also provided in the readme.md file in this repository.

In this walkthrough, you will:

Download the Spring PetClinic application
Obtain your cluster connection string
Update and run the application locally

Prerequisites

Git
Yugabyte Cloud cluster
- Your computer IP address must be in an IP allow list

Clone the Spring Data YugabyteDB PetClinic application

On your computer, clone the Spring PetClinic sample application built with Spring Data YugabyteDB:

$ git clone https://github.com/yugabyte/petclinic-spring-data-yugabytedb.git

Cloning into 'petclinic-spring-data-yugabytedb'...
remote: Enumerating objects: 177, done.
remote: Counting objects: 100% (177/177), done.
remote: Compressing objects: 100% (121/121), done.
remote: Total 177 (delta 43), reused 171 (delta 37), pack-reused 0
Receiving objects: 100% (177/177), 1.02 MiB | 1.28 MiB/s, done.
Resolving deltas: 100% (43/43), done.

Go to the petclinic-spring-data-yugabytedb directory.
```
$ cd petclinic-spring-data-yugabytedb
```

Install the certificate and copy the connection string

Sign in to Yugabyte Cloud, select your cluster, and click Connect.
Click Connect to your Application.
Click Download CA Cert to download the cluster root.crt certificate to your computer, and move the file to the ~/.postgresql directory.
```
$ mv ~/Downloads/root.crt ~/.postgresql/root.crt
```
Under Add this connection string into your application, copy the YSQL connection string.

The connection string is in the form
```
postgresql://<DB USER>:<DB PASSWORD>@[host]:[port]/[database]?ssl=true&sslmode=verify-full&sslrootcert=<ROOT_CERT_PATH>
```
Edit the connection string to retain only the host, port (5433), database (by default, yugabyte), ssl, and sslmode entries. For example:
```
postgresql://[host]:5433/yugabyte?ssl=true&sslmode=verify-full
```

Connect and run the application

On your computer, update the contents of the spring-petclinic/src/main/resources/application.yml file by updating the yugabyte:datasource:url with the modified YSQL connection string, and username and password with your YugabyteDB database credentials.

The connection string replaces the url after jdbc:, as follows:
```
yugabyte:
datasource:
    url: jdbc:[modified YSQL connection string]
    load-balance: true
    username: [user]
    password: [password]
```
where [modified YSQL connection string] is the modified YSQL connection string, and [user] and [password] are the credentials for the database.

Run the PetClinic application using the following command:

$ ./mvnw spring-boot:run

[INFO] Scanning for projects...
[INFO] 
[INFO] ----< org.springframework.samples:petclinic-spring-data-yugabytedb >----
[INFO] Building petclinic 2.1.0.BUILD-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] >>> spring-boot-maven-plugin:2.5.4:run (default-cli) > test-compile @ petclinic-spring-data-yugabytedb >>>

Flyway configures the Yugabyte database with the Petclinic schema and loads the sample data.

Go to http://localhost:8080.

The PetClinic application is now running locally and is connected to your Yugabyte Cloud cluster.

PetClinic application running

Explore PetClinic

In the Petclinic app, click Find Owners, then click Add Owner.
Enter owner details and click Add Owner to add the new owner.
In Yugabyte Cloud, select your cluster, click Connect and choose Launch Cloud Shell.
Click Confirm to open the shell in a new browser window. The shell can take up to 30 seconds to appear.
Enter your password.

At the shell prompt, display the schema of the owner table.

yugabyte=# \d owner

                                    Table "public.owner"
Column   |          Type          | Collation | Nullable |             Default              
------------+------------------------+-----------+----------+----------------------------------
id         | integer                |           | not null | generated by default as identity
first_name | character varying(30)  |           |          | 
last_name  | character varying(30)  |           |          | 
address    | character varying(255) |           |          | 
city       | character varying(80)  |           |          | 
telephone  | character varying(20)  |           |          | 
Indexes:
    "owner_pkey" PRIMARY KEY, lsm (id HASH)
    "owner_last_name" lsm (lower(last_name::text) HASH)
Referenced by:
    TABLE "pet" CONSTRAINT "fk_pet_owners" FOREIGN KEY (owner_id) REFERENCES owner(id)

Run a query to select the id, first_name, and last_name columns.

yugabyte=# SELECT id, first_name, last_name FROM owner;

 id | first_name | last_name 
----+------------+-----------
  5 | Peter      | McTavish
  1 | George     | Franklin
 11 | Mary       | Stewart
  6 | Jean       | Coleman
  7 | Jeff       | Black
  9 | David      | Schroeder
 10 | Carlos     | Estaban
  4 | Harold     | Davis
  2 | Betty      | Davis
  8 | Maria      | Escobito
  3 | Eduardo    | Rodriquez
(11 rows)