How to iterate through a list of strings in json using java

Question

I have to iterate through a List of Mapper and maper is a list of strings, my json looks like:

{ "aa":{ "val":"", "agl": [ { "a": "A1", "b": "B1", "c": "C1" }, { "a": "A2", "b": "B2", "c": "C2" } ] } }

The result is to get a,b and c values with iterator mode. I tried this the code below but i have the same error JSONArray[0] is not a JSONObject

List<Mapper> agl= fileDescription.get("aa").getAgl();
      JSONArray jsonArray = new JSONArray(agl);

      System.out.println(jsonArray);
      for (int i = 0; i < jsonArray.length(); i++) {

        Object jsonObj = jsonArray.getJSONObject(i);
       
        System.out.println(jsonObj);

       }

I tried also this code but it don't give me the result i need:

 Iterator iterator = agl.iterator();

      while (iterator.hasNext()) {

      System.out.println(iterator.next());

      System.out.println( iterator1.getA());

Mapper.java

public class Mapper{

@JsonProperty("a")
private String a;

@JsonProperty("b")
private  String b;

@JsonProperty("c")
private String c;

public String getA() {
return a;
}

public void setA(String a) {
  this.a= a;
}

public String getB() {
  return b;
}

public void setB(String b) {
this.b= b;
}

public String getC() {
return c;
}

public void setC(String c) {
this.c= c;
}


@Override
public String toString() {

return "{\"a\":" + "\""+a+ "\"" + ", \"b\":" + "\"" + b + "\"" + ", \"c\":" + "\"" + c + "\"" + "}";
 }
 }

Answer 1

I think you're misusing the type system. You already have a valid list to iterate. Don't create another one

List<Mapper> agl= fileDescription.get("aa").getAgl();
Iterator<Mapper> iterator = agl.iterator();
while (iterator.hasNext()) {
    Mapper m = iterator.next();
    System.out.println(m.getA());
} 

Or simply

List<Mapper> agl= fileDescription.get("aa").getAgl();
for (Mapper m : agl) {
    System.out.println(m.getA());
}

Or agl.forEach(m -> System.out.println(m.getA()));