How can i concatenate json format using parse

Question

I have created API URL for using autocomplete functionality as I give address in text box it display the related list of addresses. I need concatenate some address fields such as city, postcode, city code it display the next textbox. Please find below my JSON file and class. can you please suggest me what should I need to changes.

global class frenchaddress {

public String accName{get;set;}
public Id accId{get;set;}

public PageReference refresh(){
    return null;
}
  @RemoteAction
  global static List<String> restapi(string accName){

   string jsonStr;  
        Http h = new Http();
        HttpRequest req = new HttpRequest();
        req.setEndpoint('http://api-adresse.data.gouv.fr/search/?q=' + accName+ '');
        req.setHeader('Accept','application/JSON');
        req.setMethod('GET');
        HttpResponse res = h.send(req);
        system.debug('res.getBody()===>'+res.getBody().replace('\n', ''));
        List<String> calOut = new List<String>();

        jsonStr= res.getBody();

        JSONParser parser = JSON.createParser(jsonStr);

        while (parser.nextToken() != null) { 
        if (parser.getCurrentToken() == JSONToken.FIELD_NAME) {

         String fieldName = parser.getText();

           if(fieldName == 'label'){
              parser.nextToken();
             calOut.add(parser.getText());               
           }        

             if(fieldName == 'context'){
               parser.nextToken();
             calOut.add(parser.getText());               
           }
              if(fieldName == 'city'){
              system.debug('city  ---->'+parser.getText());  
              parser.nextToken();
              calOut.add(parser.getText());               
           }    
                    }
                }   

          return calOut;

      }
    }

JSON File:

Answer 1

It sounds like your @RemoteAction should return multiple addresses where each address looks like "city, postcode, citycode". For that to work I would expect that the JSON returned would be an array of the objects you post in the question not a single object.

The easiest way to parse such a structure is to submit an example of it to JSON2Apex and use the code that is generated.

The return type of your @RemoteAction method remains List<String> but each item in the list is:

calOut.add(p.city + ', ' + p.postcode + ', ' + p.citycode);

assuming p is a reference to the properties field of one of the returned and parsed objects.

PS

The names here depend on what the JSON fields are called but the code would look something like this:

List<String> calOut = new List<String>();
JSON2Apex parsed = JSON2Apex.parse(res.getBody());
for (JSON2Apex.Feature f : parsed.feature) {
    JSON2Apex.Properties p = f.properties;
    calOut.add(p.city + ', ' + p.postcode + ', ' + p.citycode);
}
return calOut;

Answer 2

Change the static method return type to string from the List<String> and

return the calOut list variable as

  @RemoteAction
  global static List<String> restapi(string accName)
  {

        string jsonStr;  
        Http h = new Http();
        HttpRequest req = new HttpRequest();
        req.setEndpoint('http://api-adresse.data.gouv.fr/search/?q=' + accName+ '');
        req.setHeader('Accept','application/JSON');
        req.setMethod('GET');
        HttpResponse res = h.send(req);
        system.debug('res.getBody()===>'+res.getBody().replace('\n', ''));
        List<String> calOut = new List<String>();

        List<String> finalcalOut = new List<String>();

        jsonStr= res.getBody();

        JSONParser parser = JSON.createParser(jsonStr);

        while (parser.nextToken() != null) 
        { 
            if (parser.getCurrentToken() == JSONToken.FIELD_NAME) 
            {

               String fieldName = parser.getText();

               if(fieldName == 'label')
               {
                  parser.nextToken();
                  calOut.add(parser.getText());               
               }        

               if(fieldName == 'context')
               {
                    parser.nextToken();
                    calOut.add(parser.getText());               
               }
               if(fieldName == 'city')
               {
                  system.debug('city  ---->'+parser.getText());  
                  parser.nextToken();
                  calOut.add(parser.getText());               
               }    
             }
             finalcalOut.add( String.join(calOut,', '); );
         }   
         return finalcalOut;
      }
    }

You would be getting something like

51, Marren, Champagne-Ardenne, Sezanne, 51120

Answer 3

I prefer use a class as model to parse a JSON

I change your code to do it easier

global class frenchaddress {

public String accName{get;set;}
public Id accId{get;set;}

public PageReference refresh(){
    return null;
}
  @RemoteAction
  global static List<String> restapi(string accName){

   string jsonStr;  
    Http h = new Http();
    HttpRequest req = new HttpRequest();
    req.setEndpoint('http://api-adresse.data.gouv.fr/search/?q=' + accName+ '');
    req.setHeader('Accept','application/JSON');
    req.setMethod('GET');
    HttpResponse res = h.send(req);
    system.debug('res.getBody()===>'+res.getBody().replace('\n', ''));
    List<String> calOut = new List<String>();

    jsonStr= res.getBody();

    AddressResponse responseClass =(AddressResponse) JSON.deserialize(jsonStr, AddressResponse.class);
    if(responseClass.properties != null){
        return responseClass.properties.getFullAddress();
    } else {
        return null;
    }

  }
}


// CLASS MODEL RESPONSE CALL OUT APi-Adresse-DATA
public class AddressResponse{
    String type;
    AddressResponseProperties properties
}

public class AddressResponseProperties{
    public Strinc city;
    public String label;
    public String id;
    public String postcode;
    public String name;
    public String citycode;
    public String ontext;
    public Decimal score;
    public String type;

    public String[] getFullAddress(){
        return new String{this.city,this.citiycode,this.postcode};
    }
}