If you are struggling to arrange the "'s the correct syntax would be

String jsonRequestString = "{\"access_code\" : \""+code+"\" , ";

Instead of formatting Json string manually, which takes alot of effort, consider using a library or util.

For ex (going to use Jackson library) :

Request re = new Request();
re.setCode(code);
...
ObjectMapper mapper = new ObjectMapper();
String jsonStr = mapper.writeValueAsString(re);

If you don't want to directly convert your input to the expected Object you could create a JSONObject from your input like

JSONObject root = new JSONObject(input);

and then navigate from there exactly to the attribute you need e.g.:

root.getJSONArray("results").getJSONObject(0).getString("is_structured");

EDIT: (receive value under date)

root.getJSONArray("results").getJSONObject(0).getJSONObject("date").getString("value");

I suggest to use one of many JSON processing libraries available.

Examples are Gson and Jackson.

Both of them allow to convert: json string <--> object

You should start with defining domain model:

public class Person {
   private String firstName;
   private String lastName;
   // getters/setters
}

Then you should do like this (for example, for GSON):

String json = "{\"firstName\":\"Jim\",\"lastName":\"Smith\"}";
Gson gson = new Gson();
Person person = gson.fromJson(json, Person.class);

Hope this helps

You need to think from object perspective. Your outer most Object is some kind of wrapper which contains most other important objects.

I have tried to convert the JSON to appropriate object structure. I hope you get my point. Please add missing objects.

public class OuterMainObject {
    private String cod;
    private float message;
    private int cnt;
    List<WeatherObject> list = new ArrayList<WeatherObject>();
    private City city;

}

class City {

    private String id;
    private String name;
    private Coordinates coord;
    private String country;
}

class Coordinates {
    private double lat;
    private double lon;
}

class WeatherObject {
    private Date dt; 
    private Main main;
    private Weather weather;
    private Clouds clouds;
    private Wind wind;
    private Rain rain;
    private Sys sys;
    private String dt_txt;

}

As you can see I have one OuterMainObject and there are multiple objects within that outermainobject now if you try and map the objects from outside to inside you can easily relate them.

Update for comment We don't have to worry about how to detect and store the variables. There are libraries which does this for us. So for example Jackson is one of such library. Please refer to this link. This one has a nice tutorial about this conversion. All you need to focus is converting the JSON to appropriate object structure.

In your case following should do it.

OuterMainObject obj = mapper.readValue(jsonString, OuterMainObject.class);

First, create a pojo class with different getter/setter for your required fields.

  public class MyResponse(){

    private List<String> idList;
    private List<String> nombreList;
    private List<String> descList;
    private List<String> califList;

    public void setIdList(List<String> list){
    this.idList = list;
    }

    public void getIdList(){
    return idList;
    }

    public void setNombreList(List<String> list){
    this.nombreList = list;
    }

    public void getNombreList(){
    return nombreList;
    }

    public void setDescList(List<String> list){
    this.descList = list;
    }

    public void getDescList(){
    return descList;
    }

    public void setCalifList(List<String> list){
    this.califList = list;
    }

    public void getCalifList(){
    return califList;
    }

}

Now parse each response and add in the list of MyResponse type

         public MyResponse getDataJSON(String response)
                    {
                        MyResponse myResponse = new MyResponse();
                        ArrayList<String> idList = new ArrayList<String>();
                        ArrayList<String> nombreList = new ArrayList<String>();
                        ArrayList<String> descList = new ArrayList<String>();
                        ArrayList<String> califList = new ArrayList<String>();

                        try
                        {
                            JSONArray jsonArray = new JSONArray(response);

                            for(int i=0; i<jsonArray.length(); i++)
                            {
                              idList.add(jsonArray.getJSONObject(i).getString("id"));

   nombreList.add(jsonArray.getJSONObject(i).getString("nombre"));
                              descList.add(jsonArray.getJSONObject(i).getString("descripcion"));
                              califList.add(jsonArray.getJSONObject(i).getString("calificacion"));
                            }

                            myResponse.setIdList(idList);
                            myResponse.setNombreList(nombreList);
                            myResponse.setDescList(descList);
                            myResponse.setCalifList(califList);

                            return myResponse;
                        }

                        catch (Exception e)
                        {
                            e.printStackTrace();
                        }

                        return list;
                    }

To retrieve back the data from getDataJSON()

     MyResponse myResponse = getDataJSON(new String(responseBody)));
     ArrayList<String> idList = myResponse.getIdList();
     ArrayList<String> nombreList = myResponse.getNombreList();
     ArrayList<String> descList = myResponse.getDescList();
     ArrayList<String> califList = myResponse.getCalifList();

Your user name is stored in invitees Array so you need to replace that. For that, we can use JSONObject like below,

    String body = new String(Files
            .readAllBytes(Paths.get("src/test/resources/config/environments/sharePrivately.json")));
    JSONObject jsonObject = new JSONObject(body);
    jsonObject.put("invitees", new JSONArray("[{\"username\": \"[email protected]\",\"role\": \"VIEWER\"}]"));

In your code,

response = header.body(jsonObject.toString())
            .when()
            .post("/shares")
            .then()
            .assertThat()
            .extract()
            .response();

Output:

{
    "duration": "NO_EXPIRE",
    "invitees": [
        {
            "role": "VIEWER",
            "username": "[email protected]"
        }
    ],
    "invitationMessage": "",
    "type": "FILE",
    "items": [
        {
            "uuid": "shdy28-9b03-4c21-9c80-f96f31f9cee9",
            "projectId": "65ht8f99694454a658yef17a95e8f"
        }
    ]
}

You need to use below import,

    <dependency>
        <groupId>org.json</groupId>
        <artifactId>json</artifactId>
        <version>20160212</version>
    </dependency>