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？
解决方法
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);