Class cast exception [JSONArray cannot be cast to org.json.simple.JSONObject]

Question

I have a json file like this

[ {
    "id":"serve-coffee",
    "tags":[ {
        "name": "@tag1", "line": 1
    }
    ],
    "description":"Coffee should not be served\n",
    "name":"Serve coffee",
    "keyword":"Feature",
    "line":2,
    "elements":[ {
        "id": "serve-coffee;buy-last-coffee", "tags":[ {
            "name": "@tag2", "line": 6
        }
        ],
        "description":"",
        "name":"Buy last coffee",
        "keyword":"Scenario",
        "line":7,
        "steps":[ {
            "name": "there are 1 coffees left in the machine", "keyword": "Given ", "line": 8
        }
        ,
        {
            "name": "I have deposited 1$", "keyword": "And ", "line": 9
        }
        ],
        "type":"scenario"
    }
    ],
    "uri":"src\/test\/resources\/traffic-remove-locations.feature"
}

]

Iam trying to convert the above json file to JSONObject.But am getting class cast exception "java.lang.ClassCastException: org.json.simple.JSONArray cannot be cast to org.json.simple.JSONObject"

code

public static JSONObject convertFileToJSON(String fileName) throws ParseException {

        // Read from File to String
        JSONParser parser = new JSONParser();
        JSONObject jsonObject = null;
        try {
            Object object = parser.parse(new FileReader(fileName));         
            jsonObject = (JSONObject) object;   // Getting classCast Exception here.

        } catch (FileNotFoundException e) {

        } catch (IOException ioe) {

        }       
        return jsonObject;
    }

but when i changed the line jsonObject = (JSONObject) object; to JSONArray jsonArray = (JSONObject)object the exception disappears. But if am casting to JSONArray then how can i get the values like id,tags and description from JSONArray. please provide a suggestion guys

Neatname · Accepted Answer · 2017-02-18 02:51:55Z

Your JSON file represents an array with one object in it. So if that were a Java data structure, you're effectively doing this:

int[] arr = {5};
int i = (int)arr;

This obviously doesn't work because you can't cast an array to a singular object. What you actually want to do it pull out the first element of the array. To continue the Java example, you want to do

int[] arr = {5};
int i = (int)arr[0];

With the JSON stuff, your parser.parse() call returns a JSONArray, not a JSONObject. So you'll need to do something like this:

public static JSONObject convertFileToJSON(String fileName) throws ParseException {
    JSONParser parser = new JSONParser();
    JSONObject jsonObject = null;
    try {
        JSONArray array = (JSONArray) parser.parse(new FileReader(fileName));         
        jsonObject = array.getJsonObject(0);

    } catch (FileNotFoundException e) {

    } catch (IOException ioe) {

    }       
    return jsonObject;
}

Kiran Kumar · Accepted Answer · 2019-02-11 10:49:49Z

2

Try casting to JsonArray and then cast access the objects one by one with help of the index from the JSON array.

 Object object = parser.parse(new FileReader(fileName));         
 JsonArray  jsonArr = (JsonArray) object;   // Getting c
 jsonObject jsonObj = jsonArr.get(0);  //use index to access like a list

edited Feb 11, 2019 at 10:49

answered Feb 18, 2017 at 2:47

Kiran Kumar

1,0517 silver badges20 bronze badges

Comments

rahulnikhare · Accepted Answer · 2018-04-25 06:44:45Z

I was also facing the same issue. I did the below changes to make it work. Below is my sample JSON. {

"routes": [{

        "startTime": 1520319414,
        "routeInfo": [{
                "routePart": 0,
                "transType": "WALK",
                "transDetails": {
                    "startLoc": {
                        "lat": 28.6434862,
                        "lon": 77.22542659999999
                    }
                }
            }, {
                "routePart": 1,
                "transType": "BUS",
                "transDetails": {
                    "routeNumber": "307-U",
                    "interStopDetails": [{
                            "seq": 1,
                            "name": "test1",
                            "loc": {
                                "lat": 28.64302,
                                "lon": 77.2260367
                            },
                            "eta": 1520319600
                        }
                    ]
                }
            }
        ],
        "totalTime": 5742
    }
]

}

Solution to Parse: JSONObject obj = (JSONObject) jsonParser.parse(new FileReader(FilepathDummy));

        JSONArray jsonRoutes=  (JSONArray) obj.get("routes"); //Gives Main JSoN

        JSONObject  routeJsonObject = (JSONObject) jsonRoutes.get(0); // Route Array into JSON

        JSONArray routeInfoArray = (JSONArray) routeJsonObject.get("routeInfo"); //  RouteInfo Array

Hope this solve your problem.

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