How to get ResponseEntity's value in Spring Boot?

Question

I'm newbie in Spring Boot. I got response from API with responseEntity in Spring Boot. I returned value of response. But I want define an array/json and set response value to this array/json. After that, I want to get specific value of this array. For example;

returned value:

{"id":"123456789","license":"6688","code":"D8B1H832EE45"}

I want to take only id's value 123456789.

something like;

array['id']

How can I do it? Help me please.

@GetMapping("/test")
public ResponseEntity<String> getmc() {

    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_JSON);
    headers.set("Authorization", "Bearer " + restTemplate.getAccessToken());

    HttpEntity<String> entity = new HttpEntity<>(null, headers);

    ResponseEntity x = restTemplate.exchange("https://api.x.com/v1/demo", HttpMethod.GET, entity, String.class);

    return restTemplate.exchange("https://api.x.com/v1/demo", HttpMethod.GET, entity, String.class);
}

it's wrong i know but i just want something like: x.getBody('id');

result: 123456789

Answer 1

You could model a Pojo (Plain old java object) based on the json like the following:

public class Pojo {
    private String id;
    private int license;
    private String code;

    public String getId() { return this.id;}
    public String getLicense() { return this.license;}
    public String getCode() { return this.code;}
}

Then change your endpoint to the following signature:

@GetMapping("/test")
public ResponseEntity<String> getmc() {

    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_JSON);
    headers.set("Authorization", "Bearer " + restTemplate.getAccessToken());

    HttpEntity<Pojo> entity = new HttpEntity<>(null, headers);

    ResponseEntity x = restTemplate.exchange("https://api.x.com/v1/demo", HttpMethod.GET, entity, Pojo.class);

    return ResponseEntity.ok(entity.getId());
}