I know this may be simple. However, I just can't get it to work.
So I am trying to use Spring RestTemplate to map my JSON data. I have following JSON response from a rest call.
{
"message":"ok",
"status":"ok",
"data":[
{"Name":"Yo",
"Address":"100 Test Rd"},
{...},
{...}
]
}
And here is the class I am trying to map it to.
@JsonIgnoreProperties(ignoreUnknown = true)
public class Response implements Serializable {
private String message;
private String status;
private List<Data> data;
// I could also use a array instead
// private Data[] data;
}
Here is my Data class:
@JsonIgnoreProperties(ignoreUnknown = true)
public class Data implements Serializable {
private String Name;
private String Address;
}
Here is the code I used to call RestTemplate:
public Reponse getResponse() {
ResponseEntity<Reponse> responseEntity = restTemplate.getForEntity(Url, Reponse.class);
return responseEntity.getBody();
}
Now here comes the problem. I was able to get "message" and "status", But when I try to log/print data, it shows null. Not exactly sure what's going on here. I really could use some help. Thanks.
I was having a similar issue with RestTemplate not mapping nested JSON objects to my class model also, after much frustration I decided to retrieve my JSON as a String(instead of converting directly to my target object) using RestTemplate and then use the google Gson library to convert my String to my target entity.
pom.xml
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.2.4</version>
</dependency>
code to call RestTemplate:
ResponseEntity<String> responseEntity = restTemplate.getForEntity(Url,String.class);
Gson gson = new GsonBuilder().create();
Response reponse = gson.fromJson(responseEntity , Response.class);
Unfortunately I was unable to find out why my nested objects were not mapped using RestTemplate the first place but I hope this workaround helps!
I had a similar issue when reading Json data from REST API using Rest Template. To resolve declare getters and setters for the List:
@JsonIgnoreProperties(ignoreUnknown = true)
public class Response implements Serializable {
private String message;
private String status;
private List<Data> data;
// getters and Setters for the list.
}
The RestTemplate will internally map the values from the listarray to the corresponding array.
Annotate property "data" with @JsonUnwrapped as below
@JsonIgnoreProperties(ignoreUnknown = true)
public class Response implements Serializable {
private String message;
private String status;
@JsonUnwrapped
private List<Data> data;
}
I ran into the same issue. Annotate with @JsonProperty
:
@JsonIgnoreProperties(ignoreUnknown = true)
public class Data implements Serializable {
@JsonProperty("Name")
private String name;
@JsonProperty("Address")
private String address;
// getters / setters for name and address
}
The fields of your Data
class should now get populated, and you can name your fields independent of the JSON representation (e.g. name
instead of Name
).
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