I'm Unable to deserialize an HTTP JSON object response

Question

I'm trying to deserialize http json output . Getting an ERROR :System.JSONException: Malformed JSON: Expected '[' at the beginning of List/Set

 public static void syncBC(){
        HttpResponse respond = getrespond();

        if(respond.getStatusCode()==200){

                list<customerLedgerEntry> clist= new customerLedgerEntry().parse(respond.getbody());

        }
    }
    public static HttpResponse getrespond(){
        Http http = new Http();
    HttpRequest request = new HttpRequest();
    request.setEndpoint ('callout:Bc_test/PBCLE');
    request.setHeader('Accept','*/*');
    request.setMethod('GET');
    request.setTimeout(40000);
        HttpResponse response = Http.send(request);
        return response;
    }

    public class customerLedgerEntry{
        public String Entry_No;
        public Date Posting_Date;
        public String Document_Type;
        public String Document_No;
        public String Customer_No;
        public Decimal Amount_LCY;
        public Decimal Amount;
        public Date Initial_Entry_Due_Date;

        public list<customerLedgerEntry> parse(String json){

            return(list<customerLedgerEntry>) System.JSON.deserialize(json, list<customerLedgerEntry>.class);

        }

    }

Here is the JSON output example:

       {"@odata.context":"https://api.businesscentral.dynamics.com/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
            "value":[{"@odata.etag":"W/\"xxxxxxxxxxxxxxxxxxxxxxx\"",
            "Entry_No":1,"Posting_Date":"2018-11-05","Entry_Type":"Initial Entry","Document_Type":"xxx",
"Document_No":"xxx","Customer_No":"13",
            "Initial_Entry_Global_Dim_1":"",
        "Initial_Entry_Global_Dim_2":"",
        "Currency_Code":"","Amount":-9,
        "Amount_LCY":-9,"Debit_Amount":0,"Debit_Amount_LCY":0,
            "Credit_Amount":9,
        "Credit_Amount_LCY":9,
        "Initial_Entry_Due_Date":"2018-11-05",
        "User_ID":"xxxx","xxx":"","Reason_Code":"","Unapplied":false,
            "Unapplied_by_Entry_No":0,
    "Cust_Ledger_Entry_No":xxx},

    {"@odata.etag":"W/\"xxxxxxxxxxxxxxxxxxxxxxx\"",
    "Entry_No":2,"Posting_Date":"2018-11-21",
            "Entry_Type":"Initial Entry","Document_Type":"xxx",
    "Document_No":"1234","Customer_No":"5423","Initial_Entry_Global_Dim_1":"",
            "Initial_Entry_Global_Dim_2":"","Currency_Code":"","Amount":-91234.84,"Amount_LCY":-91234.84,"Debit_Amount":0,"Debit_Amount_LCY":0,
            "Credit_Amount":91234.84,"Credit_Amount_LCY":91234.84,"Initial_Entry_Due_Date":"2018-11-21","User_ID":"NANCYR","xxx":"","Reason_Code":"",
            "Unapplied":false,"Unapplied_by_Entry_No":0,"Cust_Ledger_Entry_No":xxx}]}

Answer 1

First, you have to deserialized untyped as your JSON is not a list of customerLedgerEntry. Then you can deserialize typed.

I have removed some of the invalid values from your JSON, and its working fine now. For Demo, I have just kept one record. See this is how it works.

Map<String, Object> jsonMap =   (Map<String, Object>) JSON.deserializeUntyped('{ "@odata.context":"https://api.businesscentral.dynamics.com/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", "value":[ { "Posting_Date":"2018-11-21", "Entry_Type":"Initial Entry", "Document_Type":"xxx", "Document_No":"1234", "Customer_No":"5423"} ] }');

list<object> entrylisttemp = (list<object>)jsonMap.get('value');
list<testDeserialize.customerLedgerEntry> entries = (list<testDeserialize.customerLedgerEntry>)System.JSON.deserialize(JSON.serialize(entrylisttemp), list<testDeserialize.customerLedgerEntry>.class);
System.debug(entries);