java – Gson使用不同的值类型反序列化json

我正在尝试使用Gson反序列化JSONArray,其中一个值的类型可以变化,值“in_wanted”可以是布尔值或JSONObject.

in_wanted as boolean:

{
"movies": [
        {
            "title": "example boolean",
            "in_wanted": false
        }
    ]           
}

in_wanted作为JSONObject:

{
"movies": [
        {
            "title": "example object",
            "in_wanted": {
                "profile": {
                    "value": false
                }
            }
        }
    ]           
}

我需要对象,只要它可用,我需要一个反序列化器,只要“in_wanted”的值是一个布尔值,就返回null.用Gson做这件事最好的方法是什么?

最佳答案
您可以使用自定义反序列化器执行此操作.在开始时,我们应该创建可以代表您的JSON的数据模型.

class JsonEntity {

    private List<Movie> movies;

    public List<Movie> getMovies() {
        return movies;
    }

    public void setMovies(List<Movie> movies) {
        this.movies = movies;
    }

    @Override
    public String toString() {
        return "JsonEntity [movies=" + movies + "]";
    }
}

class Movie {

    private String title;
    private Profile in_wanted;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public Profile getIn_wanted() {
        return in_wanted;
    }

    public void setIn_wanted(Profile in_wanted) {
        this.in_wanted = in_wanted;
    }

    @Override
    public String toString() {
        return "Movie [title=" + title + ", in_wanted=" + in_wanted + "]";
    }
}

class Profile {

    private boolean value;

    public boolean isValue() {
        return value;
    }

    public void setValue(boolean value) {
        this.value = value;
    }

    @Override
    public String toString() {
        return String.valueOf(value);
    }
}

现在,当我们有所有需要的类时,我们应该实现新的自定义反序列化器:

class ProfileJsonDeserializer implements JsonDeserializer<Profile> {
    @Override
    public Profile deserialize(JsonElement jsonElement, Type type,
            JsonDeserializationContext context) throws JsonParseException {
        if (jsonElement.isJsonPrimitive()) {
            return null;
        }

        return context.deserialize(jsonElement, JsonProfile.class);
    }
}

class JsonProfile extends Profile {

}

请查看JsonProfile类.我们必须创建它以避免“反序列化循环”(棘手的部分).

现在我们可以用测试方法测试我们的解决方案:

GsonBuilder builder = new GsonBuilder();
builder.registerTypeAdapter(Profile.class, new ProfileJsonDeserializer());
Gson gson = builder.create();

JsonEntity jsonEntity = gson.fromJson(new FileReader("/tmp/json.txt"),
        JsonEntity.class);
System.out.println(jsonEntity);

转载注明原文:java – Gson使用不同的值类型反序列化json - 代码日志