Java Rest Template.java

Java Rest Template.java

<!-- https://mvnrepository.com/artifact/org.modelmapper/modelmapper -->
		<dependency>
			<groupId>org.modelmapper</groupId>
			<artifactId>modelmapper</artifactId>
			<version>3.2.2</version>
		</dependency>

.......................................................................................................
package com.example.DemoApp.service;

import com.example.DemoApp.Dtos.BirdDTO;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.modelmapper.ModelMapper;
import org.springframework.web.util.UriComponentsBuilder;

import java.util.*;

import org.springframework.http.*;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;

import java.util.List;
import lombok.ToString;


@Service
public class RestTemplateBird {
    // final static String url = "https://www.freetestapi.com/api/v1/birds";
    final static String birdURL = "http://127.0.0.1:8000/dummy/birds?count=100";
    final static String postURL = "http://127.0.0.1:8000/dummy/post_it_1/";
    RestTemplate restTemplate = new RestTemplate();

    public List<BirdDTO>  callAPIV1() {
        List<BirdDTO> birdsDTOList = new ArrayList<>();
        try {
            // can't use here because response is list of map
            // ResponseEntity<BirdDTO> response = restTemplate.getForEntity(url, BirdDTO.class);

            ResponseEntity<String> response = restTemplate.getForEntity(birdURL, String.class);
            if (response.getStatusCode().is2xxSuccessful()) {
                String jsonStr = response.getBody();

                ObjectMapper objectMapper = new ObjectMapper();
                List<Map<String, Object>> mapList = objectMapper.readValue(jsonStr, List.class);

                for (Map<String, Object> mapBird : mapList) {
                    BirdDTO birdDTO = new BirdDTO();
                    ModelMapper modelMapper = new ModelMapper();
                    BirdDTO birdObj = modelMapper.map(mapBird, BirdDTO.class); // Assuming 'age' is an Integer
                    birdsDTOList.add(birdObj);
                }
                return birdsDTOList;
            } else {
                System.out.println("Failed to retrieve data");
                return birdsDTOList;
            }
        } catch (RestClientException e) {
            System.out.println("Error calling API: " + e.getMessage());
        } catch (JsonMappingException e) {
            throw new RuntimeException(e);
        } catch (JsonProcessingException e) {
            throw new RuntimeException(e);
        }
        return null;
    }

    public List<Map<String, Object>> callAPIV2() throws JsonProcessingException {
        HttpHeaders headers = new HttpHeaders();
        headers.add("trace-id", "some-trace-id");
        headers.setContentType(MediaType.APPLICATION_JSON);
        HttpEntity<Map<String, Object>> requestEntity = new HttpEntity<>(headers);

        UriComponentsBuilder uriBuilder = UriComponentsBuilder.fromHttpUrl(birdURL)
                .queryParam("count", 2);


        ResponseEntity<String> response = restTemplate.exchange(
                uriBuilder.toUriString(),
                HttpMethod.GET,
                requestEntity,
                String.class
        );

        if (response.getStatusCode() == HttpStatus.OK) {
            String jsonStr = response.getBody();
            ObjectMapper OMapper = new ObjectMapper();
            List<Map<String, Object>> mapList = OMapper.readValue(jsonStr, List.class);
            return mapList;
        } else {
            System.out.println("Error in Calling the API");
            return null;
        }
    }

    public Map<String, Object> callPOSTAPIV1(Map<String, Object> reqBody) throws JsonProcessingException {

        HttpHeaders headers = new HttpHeaders();
        headers.add("trace_id", "some-trace-id");
        headers.setContentType(MediaType.APPLICATION_JSON);

        HttpEntity<Map<String, Object>> requestEntity = new HttpEntity<>(reqBody, headers);
        ResponseEntity<String> response = restTemplate.exchange(
                postURL,
                HttpMethod.POST,
                requestEntity,
                String.class
        );

        if (response.getStatusCode() == HttpStatus.OK) {
            String jsonStr = response.getBody();
            ObjectMapper OMapper = new ObjectMapper();
            Map<String, Object> inReturnResponse = OMapper.readValue(jsonStr, Map.class);
            return inReturnResponse;
        } else {
            System.out.println("Error in Calling the API");
            return null;
        }
    }
    
    public SuccessResponse callGETSuccess() throws JsonProcessingException {
        HttpHeaders headers = new HttpHeaders();
        HttpEntity<Map<String, Object>> requestEntity = new HttpEntity<>(headers);

        UriComponentsBuilder uriBuilder = UriComponentsBuilder.fromHttpUrl(birdURL)
                .queryParam("count", 2);


        ResponseEntity<SuccessResponse> response = restTemplate.exchange(
                uriBuilder.toUriString(),
                HttpMethod.GET,
                requestEntity,
                SuccessResponse.class
        );

        if (response.getStatusCode() == HttpStatus.OK) {
            SuccessResponse jsonStr = response.getBody();
            return jsonStr;
        } else {
            System.out.println("Error in Calling the API");
            return null;
        }
    }

}



.............................DTO (Data Transfer Object) very much like @dataclass in python........................................
package com.example.DemoApp.Dtos;

import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public class BirdDTO {

    private int id;
    private String name;
    private String species;
    private String family;
    private String habitat;

    @JsonProperty("place_of_found")
    private String placeOfFound;

    private String diet;
    private String description;

    @JsonProperty("wingspan_cm")
    private int wingspanCm;

    private double weightKg;
    private String image;
}


@Data
@AllArgsConstructor
public class SuccessResponse {
    private boolean success;
    private ArrayList<Object> data;
}