Consuming external OData service from CAP Java application

[Poorva_Sonawane]

In this blog, I am covering consuming an external OData service (Northwind) from a CAP Java application using SAP BTP destination service.

Destinations: contain the connection details for the remote communication of an application.

Pre-requisites: 

• Trial account on BTP


• Java application built using SAP Cloud Application Programming Model (CAP) deployed to SAP Business Technology Platform.

Create a Destination on BTP cockpit:

• Go to BTP subaccount -> space in which app is deployed -> instances -> create

         

Create destination service instance

 

• Once the service instance is created, click on instance name -> select destinations -> new destination

         

• Go to Referencing apps -> Click on bind instance -> select name of deployed application -> save

Consuming the destination in java code:

• Add/make sure this dependency is added you your pom.xml

         

•  We have already configured the connection information with destination northwind_api. SAP Cloud SDK provides DestinationAccessor to retrieve destination info.

 

@RequestMapping(value = "/getProducts")

    public String getProducts() {

        String DESTINATION_NAME = "northwind_api"; 

                                                        

        try {

            HttpDestination destination =

                    DestinationAccessor.getDestination(DESTINATION_NAME).asHttp();

            HttpClient client = HttpClientAccessor.getHttpClient(destination);

            HttpResponse httpResponse = null;

            try {

                httpResponse = client.execute(new HttpGet());

                if (httpResponse.getStatusLine().getStatusCode() == 200) {

                    BufferedReader reader = new BufferedReader(

                            new InputStreamReader(httpResponse.getEntity().getContent()));

                    StringBuilder result = new StringBuilder();

                    String line = null;

                    while ((line = reader.readLine()) != null) {

                        result.append(line);

                    }

                    reader.close();

                    return result.toString();

                }

            } catch (IOException e) {

                return "IOException: " + e.getMessage();

            }

        } catch (DestinationNotFoundException | DestinationAccessException e) {

            return e.getMessage();

        }

        return null;

    }

 

• Got the response as below on hitting "/getProducts" endpoint


• 

Closing:

This blog should give you a clear idea on how to consume destinations in SAP Cloud Platform Cloud Foundry environment from java code using DestinationAccessor class provided by SAP cloud SDK.