Retrieving JSON data via HTTP GET using Spring Android Framework

[arpit88dawda]

I am using spring android framework for retrieving json data via Http GET. I am getting following exception for the same :

- Could not read JSON: Can not deserialize instance of com.springandroidjsondemo.beans.LoginBean[] out of START_OBJECT token

The bean (LoginBean) is Following

package com.springandroidjsondemo.beans;

public class LoginBean {

    private String status;

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }
}

The android code is following :

HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.setAccept(Collections.singletonList(new MediaType("application", "json")));

HttpEntity<?> requestEntity = new HttpEntity<Object>(requestHeaders);
// Create a new RestTemplate instance
RestTemplate restTemplate = new RestTemplate();
// Add the Jackson message converters
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());

// Make the HTTP GET request, marshaling the response from JSON to an array of Events
ResponseEntity<LoginBean[]> responseEntity = restTemplate.exchange(url, HttpMethod.GET, requestEntity,LoginBean[].class); // getting exception here

LoginBean[] loginBean = responseEntity.getBody();
String status = loginBean[0].getStatus();

The json response from the server is following :

{"emp-data":[{"status":"true"}]}

I am not sure if any annotations are required for Jackson Marshalling

Please suggest the solution

Thanks!

[Roy Clarkson]

Hi, this is a Jackson deserialization issue. if you compare the JSON response with your LoginBean, the array of statuses is contained within the element "emp-data". However, your RestTemplate request is expecting JSON which looks like the following.

[{"status":"true"},{"status":"false"}]

You have a couple options. You can create a wrapper object around LoginBean. Or you can try annotating the LoginBean like the following:

@JsonRootName(value = "emp-data")
public class LoginBean {

    private String status;

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }
}

In order for this to work, you probably need to configure the Jackson ObjactMapper.

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true);
MappingJackson2HttpMessageConverter jackson = new MappingJackson2HttpMessageConverter();
jackson.setObjectMapper(objectMapper);
RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters().add(jackson);

[arpit88dawda]

Thanks for the solution!!