blocks|key|4634444|text|延续Brian的想法，因为我们几乎总是有许多REST资源，每个REST资源都有自己的根，所以推广反序列化可能会很有用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4634445|+class+RestDeserializer<T>+implements+JsonDeserializer<T>+{

++++private+Class<T>+mClass;
++++private+String+mKey;

++++public+RestDeserializer(Class<T>+targetClass,+String+key)+{
++++++++mClass+=+targetClass;
++++++++mKey+=+key;
++++}

++++@Override
++++public+T+deserialize(JsonElement+je,+Type+type,+JsonDeserializationContext+jdc)
++++++++++++throws+JsonParseException+{
++++++++JsonElement+content+=+je.getAsJsonObject().get(mKey);
++++++++return+new+Gson().fromJson(content,+mClass);

++++}
}|code-block|syntax|javascript|4634446|然后，为了解析上面的样本有效负载，我们可以注册GSON反序列化器：|4634447|Gson+gson+=+new+GsonBuilder()
++++.registerTypeAdapter(Content.class,+new+RestDeserializer<>(Content.class,+"content"))
++++.build();|4634448|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Continuing Brian's idea, because we almost always have many REST resources each with it's own root, it could be useful to generalize deserialization:

<pre><code> class RestDeserializer&lt;T&gt; implements JsonDeserializer&lt;T&gt; {

 private Class&lt;T&gt; mClass;
 private String mKey;

 public RestDeserializer(Class&lt;T&gt; targetClass, String key) {
 mClass = targetClass;
 mKey = key;
 }

 @Override
 public T deserialize(JsonElement je, Type type, JsonDeserializationContext jdc)
 throws JsonParseException {
 JsonElement content = je.getAsJsonObject().get(mKey);
 return new Gson().fromJson(content, mClass);

 }
}
</code></pre>

Then to parse sample payload from above, we can register GSON deserializer:

<pre><code>Gson gson = new GsonBuilder()
 .registerTypeAdapter(Content.class, new RestDeserializer&lt;&gt;(Content.class, "content"))
 .build();
</code></pre>

blocks|key|4634493|text|这是与@AYarulin相同的解决方案，但假设类名是JSON键名。这样，您只需要传递类名。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4634494|+class+RestDeserializer<T>+implements+JsonDeserializer<T>+{

++++private+Class<T>+mClass;
++++private+String+mKey;

++++public+RestDeserializer(Class<T>+targetClass)+{
++++++++mClass+=+targetClass;
++++++++mKey+=+mClass.getSimpleName();
++++}

++++@Override
++++public+T+deserialize(JsonElement+je,+Type+type,+JsonDeserializationContext+jdc)
++++++++++++throws+JsonParseException+{
++++++++JsonElement+content+=+je.getAsJsonObject().get(mKey);
++++++++return+new+Gson().fromJson(content,+mClass);

++++}
}|code-block|syntax|javascript|4634495|然后，为了解析上面的样本负载，我们可以注册GSON反序列化程序。这是有问题的，因为键是大小写敏感的，所以类名的大小写必须与JSON键的大小写匹配。|4634496|Gson+gson+=+new+GsonBuilder()
.registerTypeAdapter(Content.class,+new+RestDeserializer<>(Content.class))
.build();|4634497|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

This is the same solution as @AYarulin but assume the class name is the JSON key name. This way you only need to pass the Class name. 

<pre><code> class RestDeserializer&lt;T&gt; implements JsonDeserializer&lt;T&gt; {

 private Class&lt;T&gt; mClass;
 private String mKey;

 public RestDeserializer(Class&lt;T&gt; targetClass) {
 mClass = targetClass;
 mKey = mClass.getSimpleName();
 }

 @Override
 public T deserialize(JsonElement je, Type type, JsonDeserializationContext jdc)
 throws JsonParseException {
 JsonElement content = je.getAsJsonObject().get(mKey);
 return new Gson().fromJson(content, mClass);

 }
}
</code></pre>

Then to parse sample payload from above, we can register GSON deserializer. This is problematic as the Key is case sensitive, so the case of the class name must match the case of the JSON key. 

<pre><code>Gson gson = new GsonBuilder()
.registerTypeAdapter(Content.class, new RestDeserializer&lt;&gt;(Content.class))
.build();
</code></pre>

blocks|key|128390|text|在我的例子中，每个响应的"content“键都会改变。示例：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|128391|//+Root+is+hotel
{
++status+:+"ok",
++statusCode+:+200,
++hotels+:+[{
++++name+:+"Taj+Palace",
++++location+:+{
++++++lat+:+12
++++++lng+:+77
++++}

++},+{
++++name+:+"Plaza",+
++++location+:+{
++++++lat+:+12
++++++lng+:+77
++++}
++}]
}

//Root+is+city

{
++status+:+"ok",
++statusCode+:+200,
++city+:+{
++++name+:+"Vegas",
++++location+:+{
++++++lat+:+12
++++++lng+:+77
++++}
}|code-block|syntax|javascript|128392|在这种情况下，我使用了与上面列出的类似的解决方案，但必须对其进行调整。您可以看到here的要点。它有点太大了，不能在SOF上发布。|offset|length|128393|注释@InnerKey("content")被使用，代码的其余部分是为了方便它在Gson中的使用。|style|CODE|128394|entityMap|0|LINK|mutability|MUTABLE|url|https://gist.github.com/varunachar/e98a2c240eddc56053c5^0|0|0|14|4|0|0|2|K|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@$I|Z|J|10|1|11]]|A|$]]|$1|K|3|L|5|6|7|12|8|@$I|13|J|14|M|N]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

In my case, the "content" key would change for each response. Example:

<pre><code>// Root is hotel
{
 status : "ok",
 statusCode : 200,
 hotels : [{
 name : "Taj Palace",
 location : {
 lat : 12
 lng : 77
 }

 }, {
 name : "Plaza", 
 location : {
 lat : 12
 lng : 77
 }
 }]
}

//Root is city

{
 status : "ok",
 statusCode : 200,
 city : {
 name : "Vegas",
 location : {
 lat : 12
 lng : 77
 }
}
</code></pre>

In such cases I used a similar solution as listed above but had to tweak it. You can see the gist <a href="https://gist.github.com/varunachar/e98a2c240eddc56053c5" rel="nofollow">here</a>. It's a little too large to post it here on SOF. 

The annotation <code>@InnerKey("content")</code> is used and the rest of the code is to facilitate it's usage with Gson.

blocks|key|4634562|text|不要忘记所有类成员和内部类成员的@SerializedName和@Expose注释，GSON从JSON反序列化的成员最多。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4634563|看看https://stackoverflow.com/a/40239512/1676736|4634564|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/40239512/1676736^0|G|F|W|7|0|2|18|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@]|D|@$9|V|A|W|1|X]]|E|$]]|$1|H|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

Don't forget <code>@SerializedName</code> and <code>@Expose</code> annotations for all Class members and Inner Class members that most deserialized from JSON by GSON.

Look at <a href="https://stackoverflow.com/a/40239512/1676736">https://stackoverflow.com/a/40239512/1676736</a>

blocks|key|4634587|text|更好的解决方案可能是这样的..|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4634588|public+class+ApiResponse<T>+{
++++public+T+data;
++++public+String+status;
++++public+String+reason;
}|code-block|syntax|javascript|4634589|然后，像这样定义您的服务。|4634590|Observable<ApiResponse<YourClass>>+updateDevice(..);|4634591|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

A better solution could be this..

<pre><code>public class ApiResponse&lt;T&gt; {
 public T data;
 public String status;
 public String reason;
}
</code></pre>

Then, define your service like this..

<pre><code>Observable&lt;ApiResponse&lt;YourClass&gt;&gt; updateDevice(..);
</code></pre>

blocks|key|128474|text|有点晚了，但希望这能帮助一些人。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|128475|只需创建以下TypeAdapterFactory即可。|128476|++++public+class+ItemTypeAdapterFactory+implements+TypeAdapterFactory+{

++++++public+<T>+TypeAdapter<T>+create(Gson+gson,+final+TypeToken<T>+type)+{

++++++++final+TypeAdapter<T>+delegate+=+gson.getDelegateAdapter(this,+type);
++++++++final+TypeAdapter<JsonElement>+elementAdapter+=+gson.getAdapter(JsonElement.class);

++++++++return+new+TypeAdapter<T>()+{

++++++++++++public+void+write(JsonWriter+out,+T+value)+throws+IOException+{
++++++++++++++++delegate.write(out,+value);
++++++++++++}

++++++++++++public+T+read(JsonReader+in)+throws+IOException+{

++++++++++++++++JsonElement+jsonElement+=+elementAdapter.read(in);
++++++++++++++++if+(jsonElement.isJsonObject())+{
++++++++++++++++++++JsonObject+jsonObject+=+jsonElement.getAsJsonObject();
++++++++++++++++++++if+(jsonObject.has("content"))+{
++++++++++++++++++++++++jsonElement+=+jsonObject.get("content");
++++++++++++++++++++}
++++++++++++++++}

++++++++++++++++return+delegate.fromJsonTree(jsonElement);
++++++++++++}
++++++++}.nullSafe();
++++}
}|code-block|syntax|javascript|128477|并将其添加到GSON构建器中：|128478|.registerTypeAdapterFactory(new+ItemTypeAdapterFactory());|128479|或|128480|+yourGsonBuilder.registerTypeAdapterFactory(new+ItemTypeAdapterFactory());|128481|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|V|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

Bit late but hopefully this will help someone.

Just create following TypeAdapterFactory.

<pre><code> public class ItemTypeAdapterFactory implements TypeAdapterFactory {

 public &lt;T&gt; TypeAdapter&lt;T&gt; create(Gson gson, final TypeToken&lt;T&gt; type) {

 final TypeAdapter&lt;T&gt; delegate = gson.getDelegateAdapter(this, type);
 final TypeAdapter&lt;JsonElement&gt; elementAdapter = gson.getAdapter(JsonElement.class);

 return new TypeAdapter&lt;T&gt;() {

 public void write(JsonWriter out, T value) throws IOException {
 delegate.write(out, value);
 }

 public T read(JsonReader in) throws IOException {

 JsonElement jsonElement = elementAdapter.read(in);
 if (jsonElement.isJsonObject()) {
 JsonObject jsonObject = jsonElement.getAsJsonObject();
 if (jsonObject.has("content")) {
 jsonElement = jsonObject.get("content");
 }
 }

 return delegate.fromJsonTree(jsonElement);
 }
 }.nullSafe();
 }
}
</code></pre>

and add it into your GSON builder :

<pre><code>.registerTypeAdapterFactory(new ItemTypeAdapterFactory());
</code></pre>

or

<pre><code> yourGsonBuilder.registerTypeAdapterFactory(new ItemTypeAdapterFactory());
</code></pre>

blocks|key|128515|text|这是一个基于Brian+Roach和AYarulin的答案的Kotlin版本。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|128516|class+RestDeserializer<T>(targetClass:+Class<T>,+key:+String?)+:+JsonDeserializer<T>+{
++++val+targetClass+=+targetClass
++++val+key+=+key

++++override+fun+deserialize(json:+JsonElement?,+typeOfT:+Type?,+context:+JsonDeserializationContext?):+T+{
++++++++val+data+=+json!!.asJsonObject.get(key+?:+"")

++++++++return+Gson().fromJson(data,+targetClass)
++++}
}|code-block|syntax|javascript|128517|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here's a Kotlin version based on the answers by Brian Roach and AYarulin.

<pre><code>class RestDeserializer&lt;T&gt;(targetClass: Class&lt;T&gt;, key: String?) : JsonDeserializer&lt;T&gt; {
 val targetClass = targetClass
 val key = key

 override fun deserialize(json: JsonElement?, typeOfT: Type?, context: JsonDeserializationContext?): T {
 val data = json!!.asJsonObject.get(key ?: "")

 return Gson().fromJson(data, targetClass)
 }
}
</code></pre>

blocks|key|4634708|text|根据@Brian+Roach和@rafakob的回答，我是通过以下方式完成此操作的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4634709|来自服务器的Json响应|4634710|{
++"status":+true,
++"code":+200,
++"message":+"Success",
++"data":+{
++++"fullname":+"Rohan",
++++"role":+1
++}
}|code-block|syntax|javascript|4634711|公共数据处理程序类|4634712|public+class+ApiResponse<T>+{
++++@SerializedName("status")
++++public+boolean+status;

++++@SerializedName("code")
++++public+int+code;

++++@SerializedName("message")
++++public+String+reason;

++++@SerializedName("data")
++++public+T+content;
}|4634713|定制序列化程序|4634714|static+class+MyDeserializer<T>+implements+JsonDeserializer<T>
{
+++++@Override
++++++public+T+deserialize(JsonElement+je,+Type+type,+JsonDeserializationContext+jdc)
++++++++++++++++++++throws+JsonParseException
++++++{
++++++++++JsonElement+content+=+je.getAsJsonObject();

++++++++++//+Deserialize+it.+You+use+a+new+instance+of+Gson+to+avoid+infinite+recursion
++++++++++//+to+this+deserializer
++++++++++return+new+Gson().fromJson(content,+type);

++++++}
}|4634715|Gson对象|4634716|Gson+gson+=+new+GsonBuilder()
++++++++++++++++++++.registerTypeAdapter(ApiResponse.class,+new+MyDeserializer<ApiResponse>())
++++++++++++++++++++.create();|4634717|Api调用|4634718|+@FormUrlEncoded
+@POST("/loginUser")
+Observable<ApiResponse<Profile>>+signIn(@Field("email")+String+username,+@Field("password")+String+password);

restService.signIn(username,+password)
++++++++++++++++.observeOn(AndroidSchedulers.mainThread())
++++++++++++++++.subscribeOn(Schedulers.io())
++++++++++++++++.subscribe(new+Observer<ApiResponse<Profile>>()+{
++++++++++++++++++++@Override
++++++++++++++++++++public+void+onCompleted()+{
++++++++++++++++++++++++Log.i("login",+"On+complete");
++++++++++++++++++++}

++++++++++++++++++++@Override
++++++++++++++++++++public+void+onError(Throwable+e)+{
++++++++++++++++++++++++Log.i("login",+e.toString());
++++++++++++++++++++}

++++++++++++++++++++@Override
++++++++++++++++++++public+void+onNext(ApiResponse<Profile>+response)+{
+++++++++++++++++++++++++Profile+profile=+response.content;
+++++++++++++++++++++++++Log.i("login",+profile.getFullname());
++++++++++++++++++++}
++++++++++++++++});|4634719|entityMap^0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|13|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|16|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|17|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|18|8|@]|9|@]|A|$G|H]]|$1|U|3|V|5|6|7|19|8|@]|9|@]|A|$]]|$1|W|3|X|5|F|7|1A|8|@]|9|@]|A|$G|H]]|$1|Y|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Z|$]]

As per answer of @Brian Roach and @rafakob i done this in the following way

Json response from server

<pre><code>{
 "status": true,
 "code": 200,
 "message": "Success",
 "data": {
 "fullname": "Rohan",
 "role": 1
 }
}
</code></pre>

Common data handler class

<pre><code>public class ApiResponse&lt;T&gt; {
 @SerializedName("status")
 public boolean status;

 @SerializedName("code")
 public int code;

 @SerializedName("message")
 public String reason;

 @SerializedName("data")
 public T content;
}
</code></pre>

Custom serializer

<pre><code>static class MyDeserializer&lt;T&gt; implements JsonDeserializer&lt;T&gt;
{
 @Override
 public T deserialize(JsonElement je, Type type, JsonDeserializationContext jdc)
 throws JsonParseException
 {
 JsonElement content = je.getAsJsonObject();

 // Deserialize it. You use a new instance of Gson to avoid infinite recursion
 // to this deserializer
 return new Gson().fromJson(content, type);

 }
}
</code></pre>

Gson object

<pre><code>Gson gson = new GsonBuilder()
 .registerTypeAdapter(ApiResponse.class, new MyDeserializer&lt;ApiResponse&gt;())
 .create();
</code></pre>

Api call

<pre><code> @FormUrlEncoded
 @POST("/loginUser")
 Observable&lt;ApiResponse&lt;Profile&gt;&gt; signIn(@Field("email") String username, @Field("password") String password);

restService.signIn(username, password)
 .observeOn(AndroidSchedulers.mainThread())
 .subscribeOn(Schedulers.io())
 .subscribe(new Observer&lt;ApiResponse&lt;Profile&gt;&gt;() {
 @Override
 public void onCompleted() {
 Log.i("login", "On complete");
 }

 @Override
 public void onError(Throwable e) {
 Log.i("login", e.toString());
 }

 @Override
 public void onNext(ApiResponse&lt;Profile&gt; response) {
 Profile profile= response.content;
 Log.i("login", profile.getFullname());
 }
 });
</code></pre>

blocks|key|4634748|text|另一个简单的解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4634749|JsonObject+parsed+=+(JsonObject)+new+JsonParser().parse(jsonString);
Content+content+=+gson.fromJson(parsed.get("content"),+Content.class);|code-block|syntax|javascript|4634750|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Another simple solution:

<pre><code>JsonObject parsed = (JsonObject) new JsonParser().parse(jsonString);
Content content = gson.fromJson(parsed.get("content"), Content.class);
</code></pre>

blocks|key|128592|text|还有一种更简单的方法，只需将content子对象视为另一个类：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|128593|class+Content+{
++++var+foo+=+0
++++var+bar:+String?+=+null
}

class+Response+{
++++var+statis:+String?+=+null
++++var+reason:+String?+=+null
++++var+content:+Content?+=+null
}+|code-block|syntax|javascript|128594|现在您可以使用Response类型来反序列化json。|128595|entityMap^0|E|7|0|0|7|8|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

There is a simpler way, just consider <code>content</code> sub object as another class:
<pre class="lang-kotlin prettyprint-override"><code>class Content {
 var foo = 0
 var bar: String? = null
}

class Response {
 var statis: String? = null
 var reason: String? = null
 var content: Content? = null
} 
</code></pre>
and now you can use <code>Response</code> type to deserialize json.

I'm consuming an API from my android app, and all the JSON responses are like this:

<pre><code>{
 'status': 'OK',
 'reason': 'Everything was fine',
 'content': {
 &lt; some data here &gt;
}
</code></pre>

The problem is that all my POJOs have a <code>status</code>, <code>reason</code> fields, and inside the <code>content</code> field is the real POJO I want.

Is there any way to create a custom converter of Gson to extract always the <code>content</code> field, so retrofit returns the appropiate POJO?

Get nested JSON object with GSON using retrofit

服务器

Kotlin

JSON

我正在使用我的android应用程序的API，所有JSON响应都是这样的：{ 'status': 'OK', 'reason': 'Everything was fine', 'content': { < some data here >}问题是我所有的POJO都有一个status，r...

问使用改进的GSON获得嵌套的JSON对象
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