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Saving Objects

Focus of this section will be on learning how to save a Java object to MongoDB using the Repository pattern in Spring. Multiple approaches exist for persistence in Spring-Data, but the repository pattern offers some unique advantages, and is typically familiar to Spring-data users due to is wide adoption in JPA. We will cover how to use the pattern with MongoDB, and where some of the other options have challenges or benefits.

Update Customer Object​

Using your editor of choice, open the Customer.java file located in src/main/com/mongodb/mongobank/models

Update your Customers class to match the following. (some content omitted to brevity)

import org.springframework.data.annotation.Id;

@Document("customers")
public class Customer {
    
    @Id
    private String id;

    ...

}

@Document() tells spring-data that we want to treat this object as a document and with the collection mame of "customers".

@Id identifies the field that we want spring-data to map our _id field to in MongoDB (required field in each document, serves as the primary key)

tip

The collection name attribute is optional, but used here to make sure the collection name is plural, which tends to align with most organization naming standards.

Create Customer Repository​

Create a new package for the repository classes. And inside create a new CustomerRepository class with the signature found below.

com.mongodb.mongobank.repositories

Repository class snippet

public interface CustomerRepository extends MongoRepository<Customer, String> {

}

Update service class​

Finally Update the CustomerService class

@Autowired
CustomerRepository customerRepository

    public Customer createCustomer(Customer customer) {
        return customerRepository.save(customer);
    }

Testing​

There are example JSON data sets for the objects in the data folder in the project. Use those for examples of the data payloads.


curl --header "Content-Type: application/json" --request POST --data <example data payload goes here> http://localhost:8080/api/customers
Example Payloads

Here is an example payload for testing the customer service.

{
    "firstName":"Andy",
    "lastName":"Reid",
    "title":"Coach",
    "addresses": [{
        "city":"Kansas City",
        "street": "1 Arrowhead Way",
        "state":"MO",
        "country":"US",
        "zip":"64129"
    }]
}

Response should come back and show you are customer record with the ID field populated.

tip

You can also use the example payloads in tools like Postman if you prefer

Updating a customer​

Execute the above REST call but change some of the data attributes and observe the behavior of the customer record.

Complete for Remaining Classes​

Using the pattern above, complete the changes needed for the following objects

  • Account
  • Transaction