当对象是 JSONObject 或 JSONArray 时如何使用 GSON 解析 JSON

Question

我正在使用 Gson 将 JSON 转换为 Java 对象。我在 json 中有一个字段，我们明智的服务人员根据数据库中返回的项目数将其编码为数组或对象。问题是如何对 Java 对象进行建模以传递给 Gson 转换器以便我可以处理这两种类型？

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

Java 类只正确解析 JSON 数组

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 数据数组

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

JSON 数据对象

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

Answer 1

我想出了如何使用通用对象来做到这一点。所以现在我仍然可以使用 GSON 调用，而不必只在我需要重构对象时进行那么多手动解析，并且只需要那个特定的对象。

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

主要对象

public class Order {
    private Detail detail
}

细节类

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 类包含一个名为 type 的通用 Object，因此它可以存储 List 或一个 LinkedTreeMap，它是 JSONObject 被解析的方式。然后您必须手动将其插入到新的 Type 对象中。

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

叹息！！

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();
}