如何使用GSON WHen对象解析JSON是JSONObject还是JSONArray

Question

I am using Gson to convert JSON into a Java object. I have a field in the json that our wise services people coded as either an array or object depending on how many items come back in database. Question is how do model the Java object to pass into Gson converter so that I can handle both types?

json = new Gson().fromJson(reader, Order.class);

Java Classes only parses the JSON array properly

public class Order {
    private Detail detail
}

public class Detail {
    public String id;
    public List<Type> types;
    //// getters and setters
}

public class Type {
    public String typeId;
    public String typeName
    //// getters and setters
}

JSON data array

{
    "detail":{
        "id":"1234565",
        "types":{
            "type":[
                {"typeId":"1246565","typeName":"MyName1"},
                {"typeId":"1444445","typeName":"MyName2"}
            ]
        }
    }
}

JSON data object

{
    "detail":{
        "id":"1234565",
        "types":{
            "type":{"typeId":"1246565","typeName":"MyName1"}
        }
    }
}

Answer 1

I figured out how to do this by using a generic object. So now I can still call using GSON and not have to do that much manual parsing only when I need when I reconstitute the Objects, and only that particular object.

json = new Gson().fromJson(reader, Order.class);

Main Object

public class Order {
    private Detail detail
}

Detail Class

public class Detail {
    public String id;
    public Types types;

    //// getters and setters
    public Types getTypes() {
        return types;
    }

    public void setTypes(Types types) {
        this.types = types;
    }
}

Types class that contains a generic Object called type so it can store either a List or a LinkedTreeMap which is how JSONObject gets parsed. You have to then manually insert it into a new Type object .

public class Types {
    private Object type;

    //// getters and setters

    public Object getType() {
        return type;
    }

    public void setType(Object type) {
        this.type = type;
    }

    public List<Type> getListType() {
        if (type instanceof List) {
            return (List<Type>) type;
        } else
            return null;
    }

    public Type getObjectType() {
        if (type instanceof Type) {
            return (Type) type;
        } else if (type instanceof Map) {
            Map<String, String> map = (Map<String, String>)type;
            Type newType = new Type((String)map.get("typeId"), (String)map.get("typeName"));
            return newType;
        }
        return null;
    }

public class Type {
    private String typeId;
    private String typeName;

    public Type() {}

    public Type(String id, String name) {
        this.typeId = id;
        this.typeName = name;
    }

    //// getters and setters
    public String getTypeId() {
        return typeId;
    }

    public void setTypeId(String typeId) {
        this.typeId = typeId;
    }

    public String getTypeName() {
        return typeName;
    }

    public void setTypeName(String typeName) {
        this.typeName = typeName;
    }
}

Answer 2

Sigh!!

JsonArray typeArray; 
JsonElement typeElement = types.get("type"); 
if (typeElement.isJsonObject()) { 
    typeArray = new JsonArray();
    typeArray.add(typeElement); 
}
else {
    typeArray = (JsonArray)typeElement;
}
for (int i = 0; i < typeArray.size(); i++) {
    JsonObject typeObject = (JsonObject)(typeArray.get(i));
    typeObject.doSomethingWithThis();
}