Convert a List of json object to hashmap using jackson

Question

Is there a way to use inbuilt Jackson capabilities to convert a list of json object to HashMap using java

Explanation: Json structure that i need to parse

{
    list:[
        {
            keyId : 1,
            keyLabel : "Test 1",
            valueId: 34,
            valueLabel: "Test Lable"
        },
        {
            keyId : 2,
            keyLabel : "Test 2",
            valueId: 35,
            valueLabel: "Test Lable"
        },
        {
            keyId : 3,
            keyLabel : "Test 3",
            valueId: 36,
            valueLabel: "Test Lable"
        }
    ]
}

The object model I am expecting,

class Key{
    int keyId;
    String keyLable;

    hashCode(){
    return keyId.hashCode();
    }
}

class Value{
    int valueId;
    String valueLable;

    hashCode(){
    return valueId.hashCode();
    }
}

I need to convert the above json list to a map like this,

HashMap<Key,Value> map;

Answer 1

I would suggest to do it manually. You just have to write few lines. Something Like

    ObjectMapper jmap = new ObjectMapper();
    //Ignore value properties
    List<Key> keys = jmap.readValue("[{}, {}]", jmap.getTypeFactory().constructCollectionType(ArrayList.class, Key.class));
    //Ignore key properties
    List<Value> values = jmap.readValue("[{}, {}]", jmap.getTypeFactory().constructCollectionType(ArrayList.class, Value.class));

    Map<Key, Value> data = new HashMap<>();
    for (int i = 0; i < keys.size(); i++) {
        data.put(keys.get(i), values.get(i));
    }

Note: There is spell mismatch in your json and model (valueLabel != valueLable).