SpringBoot Rest response not deserialiazed with jackson - json

Question

I am a running a project with SpringBoot. In this project I am calling an external Rest Service. I have modeled the response items into bean.
But when I get the response back the data are not serialised into the beans.
I guess there must be some configuration missing but I cannot find what.
I have added onfiguration spring-boot-starter-test to the configuration of Maven:
The rest client:
#RunWith(SpringRunner.class)
#SpringBootTest
public class RestClientTest {
#Autowired
private RestTemplateBuilder restTemplate;
#Test
public void sayHello() {
System.out.println("Hello");
assert(true);
}
#Test
public void testGetEmployee() {
RestTemplate template = restTemplate.build();;
HttpHeaders headers = new HttpHeaders();
List<MediaType> types = new ArrayList<MediaType>();
types.add(MediaType.APPLICATION_JSON);
types.add(MediaType.APPLICATION_XML);
headers.setAccept(types);
headers.set("Authorization", "Bearer gWRdGO7sUhAXHXBnjlBCtTP");
HttpEntity<Items> entity = new HttpEntity<Items>(headers);
String uri = "https://mytest.com/employees";
//ResponseEntity<String> rec = template.exchange(uri, HttpMethod.GET, entity, String.class);
//System.out.println("Received: " + rec);
ResponseEntity<Items> rec = template.exchange(uri, HttpMethod.GET, entity, Items.class);
System.out.println("Received: " + rec);
}
}
When I inspect the elements of the response it, I get a list, all the items are with null values
#JsonFormat(shape = JsonFormat.Shape.OBJECT)
public class Item implements Serializable {
#JsonProperty
private String id;
#JsonProperty
private String name;
#JsonProperty
private String email;
#JsonProperty
private String phone;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
}
#JsonFormat(shape = JsonFormat.Shape.OBJECT)
public class Items implements Serializable {
#JsonProperty
private List<Item> items = new ArrayList<Item>();
public List<Item> getItems() {
return items;
}
}
Do you see what I am missing here?
The response is like this:
{
"items": [
{
"item": {
"id": 0,
"name": "string",
"email": "string",
"phone": "string",
Do you see what I am missing here?
Thanks
Gilles

Answer 1

The way you have implemented will try to deserialize data into Items class. But it doesn't have the required properties to deserialize. When you need to get a list of data through rest template exchange, you can get them as follows.
Get data as an array and convert it into arrayList.
Item[] itemArray = template.exchange(uri, HttpMethod.GET, entity, Item[].class).getBody();
List<Item> itemList = Arrays,asList(itemArray);
or
Use ParameterizedTypeReference to get data as a list
ResponseEntity<List<Item>> itemList = template.exchange(uri, HttpMethod.GET, entity, new ParameterizedTypeReference<List<Item>>() {});
List<Item> itemList = template.exchange(uri, HttpMethod.GET, entity, new ParameterizedTypeReference<List<Item>>() {}).getBody(); // access list directly

Answer 2

You might need to add this to your ObjectMapper:
mapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true);
And on your entity add #JsonRootName("item")