Spring MVC Project - Retrieving Population, Area, and Region Details using Rest API

To retrieve population, area, and region details for a given country using a REST API, we'll need to do the following steps:

Set Up Dependencies: We'll use Spring Boot for the project setup and Spring's RestTemplate to consume a REST API.
Consume REST API: This involves calling a third-party API (or any available API) to get the desired details.
Display in View: Once the details are fetched, we'll display them in a JSP page.

1. Project Setup:

Start with the Spring Initializr or any other means to generate a Spring Boot project. Include spring-boot-starter-web for web capabilities.

2. Consume REST API:

Let's assume you're using a fictional REST API endpoint https://api.example.com/country/{countryName} that returns country details in JSON format:

{
    "name": "CountryName",
    "population": "1234567",
    "area": "12345",
    "region": "RegionName"
}

Create a DTO:

public class Country {
    private String name;
    private String population;
    private String area;
    private String region;
    
    // Getters, setters and other methods...
}

Use RestTemplate to fetch country details:

@Service
public class CountryService {

    private static final String API_URL = "https://api.example.com/country/";

    public Country getCountryDetails(String countryName) {
        RestTemplate restTemplate = new RestTemplate();
        return restTemplate.getForObject(API_URL + countryName, Country.class);
    }
}

3. Controller and View:

Now, create a controller to handle requests and responses:

@Controller
@RequestMapping("/country")
public class CountryController {

    @Autowired
    private CountryService countryService;

    @GetMapping("/{countryName}")
    public String getCountryDetails(@PathVariable String countryName, Model model) {
        Country country = countryService.getCountryDetails(countryName);
        model.addAttribute("country", country);
        return "countryDetails";
    }
}

Finally, create a JSP view (countryDetails.jsp) to display the details:

<h1>Details for ${country.name}</h1>
<p><strong>Population:</strong> ${country.population}</p>
<p><strong>Area:</strong> ${country.area}</p>
<p><strong>Region:</strong> ${country.region}</p>

Final Thoughts:

Error handling has been omitted for simplicity but should be included (e.g., when the country isn't found).
Cache responses when applicable to reduce unnecessary API calls.
Don't forget to add exception handling, especially for cases where the third-party API might be down.
If the API requires authentication, you'd also have to add relevant headers or authentication methods to your RestTemplate call.

Spring MVC Population, Area, Region Details REST API Example:

Description: This is a basic example illustrating how to retrieve population, area, and region details using a REST API in a Spring MVC application.

Code Snippet: (Controller)

@RestController
@RequestMapping("/demographic")
public class DemographicController {

    @Autowired
    private DemographicService demographicService;

    @GetMapping("/details")
    public ResponseEntity<DemographicDetails> getDemographicDetails() {
        DemographicDetails details = demographicService.fetchDemographicDetails();
        return new ResponseEntity<>(details, HttpStatus.OK);
    }
}

(Service)

@Service
public class DemographicService {

    @Autowired
    private RestTemplate restTemplate;

    public DemographicDetails fetchDemographicDetails() {
        String apiUrl = "https://api.example.com/demographic/details";
        return restTemplate.getForObject(apiUrl, DemographicDetails.class);
    }
}

(Model)

public class DemographicDetails {

    private long population;
    private double area;
    private String region;

    // Getter and Setter
}

Retrieving Data with Spring RestTemplate in Spring MVC:

Description: This example illustrates how to retrieve data using Spring RestTemplate in a Spring MVC application.

Code Snippet: (Service)

@Service
public class DemographicService {

    public DemographicDetails fetchDemographicDetails() {
        String apiUrl = "https://api.example.com/demographic/details";
        RestTemplate restTemplate = new RestTemplate();
        return restTemplate.getForObject(apiUrl, DemographicDetails.class);
    }
}