Could not read JSON: Can not deserialize instance of hello.Country[] out of START_OBJECT token

Question

I have rest url that gives me all countries - http://api.geonames.org/countryInfoJSON?username=volodiaL.

I use RestTemplate from spring 3 to parse returned json into java objects:

RestTemplate restTemplate = new RestTemplate(); Country[] countries = restTemplate.getForObject("http://api.geonames.org/countryInfoJSON?username=volodiaL",Country[].class); 

When I run this code I get an exception:

Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of hello.Country[] out of START_OBJECT token  at [Source: sun.net.www.protocol.http.HttpURLConnection$HttpInputStream@1846149; line: 1, column: 1]     at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:164)     at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:691)     at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:685)     at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.handleNonArray(ObjectArrayDeserializer.java:222)     at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.deserialize(ObjectArrayDeserializer.java:133)     at com.fasterxml.jackson.databind.deser.std.ObjectArrayDeserializer.deserialize(ObjectArrayDeserializer.java:18)     at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2993)     at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2158)     at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.readJavaType(MappingJackson2HttpMessageConverter.java:225)     ... 7 more 

Finally my Country class:

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;  @JsonIgnoreProperties(ignoreUnknown = true) public class Country {     private String countryName;     private long geonameId;      public String getCountryName() {         return countryName;     }      public long getGeonameId() {         return geonameId;     }      @Override     public String toString() {         return countryName;     } } 

The problem is that returned json contains root element "geonames" which contains array of country elements like so:

{ "geonames": [     {         "continent": "EU",         "capital": "Andorra la Vella",         "languages": "ca",         "geonameId": 3041565,         "south": 42.42849259876837,         "isoAlpha3": "AND",         "north": 42.65604389629997,         "fipsCode": "AN",         "population": "84000",         "east": 1.7865427778319827,         "isoNumeric": "020",         "areaInSqKm": "468.0",         "countryCode": "AD",         "west": 1.4071867141112762,         "countryName": "Andorra",         "continentName": "Europe",         "currencyCode": "EUR"     } ] } 

How to tell RestTemplate to convert each element of array into Country object?

Answer 1

You need to do the following:

public class CountryInfoResponse {     @JsonProperty("geonames")    private List<Country> countries;      //getter - setter }  RestTemplate restTemplate = new RestTemplate(); List<Country> countries = restTemplate.getForObject("http://api.geonames.org/countryInfoJSON?username=volodiaL",CountryInfoResponse.class).getCountries(); 

It would be great if you could use some kind of annotation to allow you to skip levels, but it's not yet possible (see this and this)