java - 使用 gson 转换器时如何将改造用作单例？

Question

From the @jake Wharton answer you should only ever call restAdapter.create once and re-use the same instance of MyTaskService every time you need to interact with. I cannot stress this enough. You can use the regular singleton pattern in order to ensure that there only is ever a single instance of these objects that you use everywhere. A dependency injection framework would also be something that could be used to manage these instances but would be a bit overkill if you are not already utilizing it.

这是我的代码

public class MusicApi {
private static final String API_URL = "https://itunes.apple.com";
private static MusicApiInterface sMusicApiInterface;

public static MusicApiInterface getApi() {
    if (sMusicApiInterface == null) {
        sMusicApiInterface = null;
        RestAdapter restAdapter = new RestAdapter.Builder()
                .setEndpoint(API_URL)
                .build();

        sMusicApiInterface = restAdapter.create(MusicApiInterface.class);
    }
    return sMusicApiInterface;
}

public interface MusicApiInterface {
    @GET("/search?entity=musicVideo")
    NetworkResponse getMusic(@Query("term") String term);

    @GET("/search?entity=musicVideo")
    void getMusic(@Query("term") String term, Callback<NetworkResponse> networkResponseCallback);

    @GET("/search?entity=musicVideo")
    Observable<NetworkResponse> getMusicObservable(@Query("term") String term);
}

一切正常。我正在使用类型适配器，对于每个请求，我需要创建不同类型的 gson 解析并设置到适配器中。

Gson gson = new GsonBuilder().registerTypeAdapter(DiscussionViewMoreContainer.class, new ExplorerDeserializerJson())
            .create();

这让我每次都必须创建一个新的 restadapter。在我的应用程序中，一些请求并行运行。这是正确的方法吗？

Answer 1

您不必每次都创建它，只需在创建 RestAdapter 时创建一次:

public static MusicApiInterface getApi() {
    if (sMusicApiInterface == null) {
       Gson gson = new GsonBuilder()
           .registerTypeAdapter(DiscussionViewMoreContainer.class, new ExplorerDeserializerJson())
           .create();
       RestAdapter restAdapter = new RestAdapter.Builder()
            .setEndpoint(API_URL)
            .setConverter(new GsonConverter(gson))
            .build();
       sMusicApiInterface = restAdapter.create(MusicApiInterface.class);
     }
     return sMusicApiInterface;
}

如果您需要注册多个Deserializer，只需调用.registerTypeAdapter 多次使​​用Class/TypeToken 和实例自定义 反序列化器。 Gson 将根据您调用的 retrofit 方法的返回类型调用正确的方法。例如

Gson gson = new GsonBuilder()
           .registerTypeAdapter(DiscussionViewMoreContainer.class, new ExplorerDeserializerJson())
           .registerTypeAdapter(OtherModelClass.class, new OtherModelClassDeserializerJson())
           .registerTypeAdapter(OtherModelClass3.class, new OtherModelClass3DeserializerJson())