Issue with parsing the content from json file with Jackson message- JsonMappingException -Cannot deserialize as out of START ARRAY token

Question

Given the following  json file                    name     New York            number     732921            center                       latitude    38 895111                    longitude    -77 036667                                     name     San Francisco            number     298732            center                       latitude    37 783333                    longitude    -122 416667                         I prepared two classes to represent the contained data   public class Location       public String name      public int number      public GeoPoint center           public class GeoPoint       public double latitude      public double longitude      In order to parse the content from the  json file I use Jackson 2 2 x and prepared the following method   public static List lt Location gt  getLocations InputStream inputStream        ObjectMapper objectMapper   new ObjectMapper        try           TypeFactory typeFactory   objectMapper getTypeFactory            CollectionType collectionType   typeFactory constructCollectionType                                              List class  Location class           return objectMapper readValue inputStream  collectionType         catch  IOException e            e printStackTrace              return null      As long as I leave out the center property all content can be parsed  However  when I try to parse the geo-coordinates I end up with the following error message      com fasterxml jackson databind JsonMappingException  Can not deserialize instance of     com example GeoPoint out of START ARRAY token at  Source  android content res AssetManager AssetInputStream 416a5850  line  5  column  25     through reference chain  com example Location  center

User · Answer

I sorted this problem as verifying the json from JSONLint.com and then, correcting it. And this is code for the same.

String jsonStr = "[{\r\n" + "\"name\":\"New York\",\r\n" + "\"number\": \"732921\",\r\n"+ "\"center\": {\r\n" + "\"latitude\": 38.895111,\r\n"  + " \"longitude\": -77.036667\r\n" + "}\r\n" + "},\r\n" + " {\r\n"+ "\"name\": \"San Francisco\",\r\n" +\"number\":\"298732\",\r\n"+ "\"center\": {\r\n" + "    \"latitude\": 37.783333,\r\n"+ "\"longitude\": -122.416667\r\n" + "}\r\n" + "}\r\n" + "]";

ObjectMapper mapper = new ObjectMapper();
MyPojo[] jsonObj = mapper.readValue(jsonStr, MyPojo[].class);

for (MyPojo itr : jsonObj) {
    System.out.println("Val of name is: " + itr.getName());
    System.out.println("Val of number is: " + itr.getNumber());
    System.out.println("Val of latitude is: " + 
        itr.getCenter().getLatitude());
    System.out.println("Val of longitude is: " + 
        itr.getCenter().getLongitude() + "\n");
}

Note: MyPojo[].class is the class having getter and setter of json properties.

Result:

Val of name is: New York
Val of number is: 732921
Val of latitude is: 38.895111
Val of longitude is: -77.036667
Val of name is: San Francisco
Val of number is: 298732
Val of latitude is: 37.783333
Val of longitude is: -122.416667

User · Answer

JsonMappingException  out of START ARRAY token exception is thrown by Jackson object mapper as it s expecting an Object    whereas it found an Array      in response   This can be solved by replacing Object with Object   in the argument for geForObject  url  Object   class    References    Ref 1 Ref 2 Ref 3

User · Answer

Your JSON string is malformed  the type of center is an array of invalid objects  Replace   and   with   and   in the JSON string around longitude and latitude so they will be objects                    name     New York            number     732921            center                       latitude    38 895111                    longitude    -77 036667                                     name     San Francisco            number     298732            center                       latitude    37 783333                    longitude    -122 416667

User · Answer

As said  JsonMappingException  out of START ARRAY token exception is thrown by Jackson object mapper as it s expecting an Object    whereas it found an Array      in response   A simpler solution could be replacing the method getLocations with   public static List lt Location gt  getLocations InputStream inputStream        ObjectMapper objectMapper   new ObjectMapper        try           TypeReference lt List lt Location gt  gt  typeReference   new TypeReference lt  gt                return objectMapper readValue inputStream  typeReference         catch  IOException e            e printStackTrace              return null      On the other hand  if you don t have a pojo like Location  you could use   TypeReference lt List lt Map lt String  Object gt  gt  gt  typeReference   new TypeReference lt  gt        return objectMapper readValue inputStream  typeReference

[java] Issue with parsing the content from json file with Jackson & message- JsonMappingException -Cannot deserialize as out of START_ARRAY token

Examples related to java

Examples related to arrays

Examples related to json

Examples related to jackson