java.lang.ClassCastException: 类 net.sf.json.JSONObject 不能转换为类 net.sf.json.JSONArray

Question

i have a problem with JSON. an exception is thrown at this line in my code

String jsontxt = IOUtils.toString(new FileInputStream(Filename), "UTF-8");
JSONArray  root = (JSONArray) JSONSerializer.toJSON(jsontxt);

jsontxt is a String where all my JSON is stored.

and for some reason i have this exception:

Exception in thread "main" java.lang.ClassCastException: class net.sf.json.JSONObject cannot be cast to class net.sf.json.JSONArray (net.sf.json.JSONObject and net.sf.json.JSONArray are in unnamed module of loader 'app')

i validated my JSON file using Lint. Any idea where it might come from?

here is my JSON :

{
    "numero_de_permis": "A0001",
    "cycle": "2018-2020",
    "heures_transferees_du_cycle_precedent": 2,
    "activites": [{
            "description": "Cours sur la déontologie",
            "categorie": "cours",
            "heures": 14,
            "date": "2019-03-20"
        },
        {
            "description": "Séminaire sur l'architecture contemporaine",
            "categorie": "séminaire",
            "heures": 10,
            "date": "2019-01-07"
        },
        {
            "description": "Rédaction pour le magazine Architecture moderne",
            "categorie": "rédaction professionnelle",
            "heures": 6,
            "date": "2019-10-22"
        },
        {
            "description": "Participation à un groupe de discussion sur le partage des projets architecturaux de plus de 20 ans ",
            "categorie": "groupe de discussion",
            "heures": 6,
            "date": "2019-04-01"
        },
        {
            "description": "Visite d'établissements architecturaux",
            "categorie": "voyage",
            "heures": 2,
            "date": "2019-02-02"
        }
    ]
}

the value of jsontxt is the same as my jsonfile meaning it loaded correctly:

{
    "numero_de_permis": "A0001",
    "cycle": "2018-2020",
    "heures_transferees_du_cycle_precedent": 2,
    "activites": [{
            "description": "Cours sur la déontologie",
            "categorie": "cours",
            "heures": 14,
            "date": "2019-03-20"
        },
        {
            "description": "Séminaire sur l'architecture contemporaine",
            "categorie": "séminaire",
            "heures": 10,
            "date": "2019-01-07"
        },
        {
            "description": "Rédaction pour le magazine Architecture moderne",
            "categorie": "rédaction professionnelle",
            "heures": 6,
            "date": "2019-10-22"
        },
        {
            "description": "Participation à un groupe de discussion sur le partage des projets architecturaux de plus de 20 ans ",
            "categorie": "groupe de discussion",
            "heures": 6,
            "date": "2019-04-01"
        },
        {
            "description": "Visite d'établissements architecturaux",
            "categorie": "voyage",
            "heures": 2,
            "date": "2019-02-02"
        }
    ]
}

EDIT: i found a solution to my problem. thanks to Arnaud Claudel, i noticed that my JSON at the start was just an object and not an array. so doing this fixed my error:

JSONObject  root = (JSONObject) JSONSerializer.toJSON(jsontxt);

Answer 1

The problem is that you have a JSON Object, not an array.

Therefore you can't cast it to a JSONArray , cast it to JSONObject .