Spring Boot Microservice on Cloud — Mongo DB cloud integration (Part 2)

May 18, 2020 · 4 minute read

by Avinash Singh

cover-image

This article is part of the series. We will learn to use spring data and configure our database in MongoDB cloud.

In this series of tutorials, we are going to cover:

Let’s get started,

Step 1: Add the Maven Dependencies

Spring Boot provides a very convenient spring-boot-starter-data-mongodb project to add the dependencies we need to buid our entities and DAO layer.

We are also adding lombok dependency, this helps us avoid boilerplate in our java classes. Ref: lombok

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-mongodb</artifactId>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <scope>provided</scope>
    </dependency>

Step 2: Create Entity and the Repository

We are using Spring data which will generate the basic repository for us just by extending CrudRepository

To avoid empty shopping item and to display the prowess of javax validation , let’s add a bunch of validation to the shopping item name.

@Data
@Document(collection="shopping-items")
public class ShoppingItem {
	
  @Id
  private String id;
	
  @NotEmpty(message = "{shopping.list.mandatory}")
  @Pattern(regexp = "[a-zA-Z0-9]*", message = "{shopping.list.alphanumeric}")
  private String name;
}

Let’s add a validationMessages.properties file in src/main/resources.

shopping.list.alphanumeric=Shopping list name should contain alphanumeric text
shopping.list.mandatory=Shopping list name is mandatory

Step 3: Installing Mongo DB

For our database need with MongoDB, lets install MongoDB and start a database,

MongoDB community addition can be downloaded from here, https://www.mongodb.com/download-center/community

MongoDB default directories for data are , let’s create this to start mongo database.

Windows - C:/data/db

Mac - /data/db

Start Mongo DB with below command

.\mongod.exe

This starts the default database test, let’s create a new database shopping-list by running below command to open mongo db terminal

.\mongo.exe
use shopping-list

Now let’s add this new database properties in our application.yaml

data: 
      mongodb: 
          database: shopping-list
          host: localhost
          port: 27017

Step 4: Create Shopping List REST controller

Add a Repository that extends CrudRepository

public interface ShoppingListRepository extends CrudRepository<ShoppingItem, String> {
}

We created a basic REST controller in PART 1 of the series, let’s modify it will call to our repository.

We don’t have any business logic so let’s avoid a Service layer and add Repository calls in REST layer.

@RestController
@RequestMapping("/")
public class ShoppingListController {
    
	@Autowired
    public ShoppingListRepository shoppingRepo;
    
    @GetMapping
    public Iterable<ShoppingItem> getShoopingList() {
        return shoppingRepo.findAll();
    }
    
    @GetMapping("/{id}")
    public ShoppingItem getItem(@PathVariable String id) {
        return shoppingRepo.findById(id).get();
    }
    
    @PutMapping
    public ShoppingItem addShoppingList(@RequestBody @Valid ShoppingItem item) {
        return shoppingRepo.save(item);
    }
    
    @DeleteMapping("/{id}")
    public void deleteItem(@PathVariable String id) {
        shoppingRepo.deleteById(id);
    }
}

Step 5: Running the application

We are now ready to test our REST service with local MongoDB instance,

Let’s run our spring boot app, if you are not sure how to do that then please have alook at PART 1 of the series added in reference.

org.mongodb.driver.connection : Opened connection [connectionId{localValue:1, serverValue:2}] to localhost:27017
...
c.c.shoppinglist.Application: Started Application in 3.287 seconds (JVM running for 4.875)

Step 6: Testing the application

I prefer POSTMAN for testing the REST API but you can choose any other tool of your choice

We now test by adding to our list,

Make sure you have lombok installed otherwise you may see empty data coming in as Json Mapper will not be able to find getter setters for your POJO

https://projectlombok.org/setup/eclipse

PUT data with POSTMAN

postman-1

Verify Validations are working

postman-2

Verify the data in GET call

http://localhost:3024/shopping-list/

[{"id":"5ec410f1f595d85b487a9cc2","name":"Egg"},{"id":"5ec41247f963943db037e1fd","name":"Milk"}]

Verify data in MongoDB compass GUI installed with MongoDB,

mongodb-compass

Step 7: Create DB in MongoDB Cloud (Atlas)

Let’s create an account in MongoDB cloud https://cloud.mongodb.com/

Once you create your free account and login, create a free cluster, this will 2-3 minutes.

cluster-1

Once your cluster is ready , it will look like below

cluster-2

Click on the connect to create a connection, whitelist your IP address and provide a username-password,

cluster-3

cluster-3.1

Select your driver and copy the connection string,

cluster-4

Step 8: Create a spring profile and connect to MongoDB cloud

We have created our Mongo DB cloud, lets create a separate maven profile that we can use when connecting to cloud databasse.

Create a file application-cloud.yaml in src/main/resources We will use different port so it allow us to test both local and cloud db application profiles.

spring:     
  data: 
      mongodb: 
          uri: mongodb+srv://testuser:testpassword@shopping-list-cluster-vac4w.mongodb.net/test?retryWrites=true&w=majority
server: 
  port: 3025

We should configure Spring Boot to know profile to use,

We can either use Maven profiles and configure spring boot to make that profile active or directly use spring profile which is easier option. We will stick with spring profile for this tutorial.

Let’s duplicate our spring boot config,