java - how to convert JSONArray to List of Object using camel-jackson

Question

Am having the String of json array as follow

{"Compemployes":[
    {
        "id":1001,
        "name":"jhon"
        },
        {
                "id":1002,
        "name":"jhon"
        }
]}

i want to convert this this jsonarray to List<Empolyee> . for this i had added the the maven dependency "camel-jackson" and also write the pojo class for employee . but when i try to run my below code

 ObjectMapper mapper = new ObjectMapper();
 List<Employe> list = mapper.readValue(jsonString, TypeFactory.collectionType(List.class, Employe.class));

am getting the following exception.

org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of START_OBJECT token
 at [Source: java.io.StringReader@43caa144; line: 1, column: 1]

can someone pls tell what am missing or doing anyting wrong

question from:https://stackoverflow.com/questions/19271065/how-to-convert-jsonarray-to-list-of-object-using-camel-jackson

Answer 1

The problem is not in your code but in your json:

{"Compemployes":[{"id":1001,"name":"jhon"}, {"id":1002,"name":"jhon"}]}

this represents an object which contains a property Compemployes which is a list of Employee. In that case you should create that object like:

class EmployeList{
    private List<Employe> compemployes;
    (with getter an setter)
}

and to deserialize the json simply do:

EmployeList employeList = mapper.readValue(jsonString,EmployeList.class);

If your json should directly represent a list of employees it should look like:

[{"id":1001,"name":"jhon"}, {"id":1002,"name":"jhon"}]

Last remark:

List<Employee> list2 = mapper.readValue(jsonString, 
TypeFactory.collectionType(List.class, Employee.class));

TypeFactory.collectionType is deprecated you should now use something like:

List<Employee> list = mapper.readValue(jsonString,
TypeFactory.defaultInstance().constructCollectionType(List.class,  
   Employee.class));