前方高能--Retrofit

朱雀 2022-08-05 00:49 167阅读 0赞

# Retrofit #

> A type-safe REST client for Android and Java

--------------------

Android中非常有名的网络框架  
[**官网** ：http://square.github.io/retrofit/][_http_square.github.io_retrofit]  
[**参考项目**： http://square.github.io/okhttp/][http_square.github.io_okhttp]  
[**Android 示例项目**： https://github.com/goodev/RetrofitDemo][Android _ https_github.com_goodev_RetrofitDemo]

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**Retrofit** vs **Volley**  
[http://instructure.github.io/blog/2013/12/09/volley-vs-retrofit/][http_instructure.github.io_blog_2013_12_09_volley-vs-retrofit]  
提取一张图片  
![这里写图片描述][tIdZkl3.png]

//API
    public interface ApiService {
        @GET("/jobs")
        public void getJobs(Callback<Data> callback);
    }

//RestClient
    public class RestClient {
    
        private static final String BASE_URL = "https://yourapi.host.com";
        private ApiService apiService;
    
        public RestClient() {
            Gson gson = new GsonBuilder()
                    .registerTypeAdapterFactory(new ItemTypeAdapterFactory())
                    .setDateFormat("yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'SSS'Z'")
                    .create();
    
            RestAdapter restAdapter = new RestAdapter.Builder()
                    .setLogLevel(RestAdapter.LogLevel.FULL)
                    .setEndpoint(BASE_URL) 
                    .setConverter(new GsonConverter(gson))
                    .setRequestInterceptor(new SessionRequestInterceptor())
                    .setClient(new OkClient(MySSLTrust.getUnsafeOkHttpClient()))
                    .build();
    
            apiService = restAdapter.create(ApiService.class);
        }
    
        public ApiService getApiService() {
            return apiService;
        }
    }

//MySSLTrust 的SSL信任
    public class MySSLTrust {
        
        public static OkHttpClient getUnsafeOkHttpClient() {
            try {
                // Create a trust manager that does not validate certificate chains
                final TrustManager[] trustAllCerts = new TrustManager[] {
                        new X509TrustManager() {
                            @Override
                            public void checkClientTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
                            }
    
                            @Override
                            public void checkServerTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
                            }
    
                            @Override
                            public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                                return null;
                            }
                        }
                };
    
                // Install the all-trusting trust manager
                final SSLContext sslContext = SSLContext.getInstance("SSL");
                sslContext.init(null, trustAllCerts, new java.security.SecureRandom());
                // Create an ssl socket factory with our all-trusting manager
                final SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();
    
                OkHttpClient okHttpClient = new OkHttpClient();
                okHttpClient.setSslSocketFactory(sslSocketFactory);
                okHttpClient.setHostnameVerifier(new HostnameVerifier() {
                    @Override
                    public boolean verify(String hostname, SSLSession session) {
                        return true;
                    }
                });
    
                return okHttpClient;
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }
    
    
    /**
     * add Headers fro every request
     * Created by Hanks on 2015/5/18.
     */
    public class SessionRequestInterceptor implements RequestInterceptor {
        
        @Override
        public void intercept(RequestFacade request) {
            /*request.addHeader("Accept", "application/json;versions=1");
            if(isUserLoggedIn()){
                request.addHeader("Authorization",getToken());
            }*/
                request.addHeader("Authorization","huhu=")；
        }
    }

官网的几个例子：  
API Declaration

Annotations on the interface methods and its parameters indicate how a request will be handled.

REQUEST METHOD

Every method must have an HTTP annotation that provides the request method and relative URL. There are five built-in annotations: GET, POST, PUT, DELETE, and HEAD. The relative URL of the resource is specified in the annotation.

@GET("/users/list")

You can also specify query parameters in the URL.

@GET("/users/list?sort=desc")

URL MANIPULATION

A request URL can be updated dynamically using replacement blocks and parameters on the method. A replacement block is an alphanumeric string surrounded by \{ and \}. A corresponding parameter must be annotated with @Path using the same string.

@GET(“/group/\{id\}/users”)  
List groupList(@Path(“id”) int groupId);  
Query parameters can also be added.

@GET("/group/{id}/users")
    List<User> groupList(@Path("id") int groupId, @Query("sort") String sort);

For complex query parameter combinations a Map can be used.

@GET("/group/{id}/users")

List groupList(@Path(“id”) int groupId, @QueryMap Map

@Headers("Cache-Control: max-age=640000")
    @GET("/widget/list")
    List<Widget> widgetList();
    @Headers({
        "Accept: application/vnd.github.v3.full+json",
        "User-Agent: Retrofit-Sample-App"
    })

@GET("/users/{username}")

User getUser(@Path(“username”) String username);  
Note that headers do not overwrite each other. All headers with the same name will be included in the request.

A request Header can be updated dynamically using the @Header annotation. A corresponding parameter must be provided to the @Header. If the value is null, the header will be omitted. Otherwise, toString will be called on the value, and the result used.

@GET("/user")
    void getUser(@Header("Authorization") String authorization, Callback<User> callback)

Headers that need to be added to every request can be specified using a RequestInterceptor. The following code creates a RequestInterceptor that will add a User-Agent header to every request.

RequestInterceptor requestInterceptor = new RequestInterceptor() {
      @Override
      public void intercept(RequestFacade request) {
        request.addHeader("User-Agent", "Retrofit-Sample-App");
      }
    };
    
    RestAdapter restAdapter = new RestAdapter.Builder()
      .setEndpoint("https://api.github.com")
      .setRequestInterceptor(requestInterceptor)
      .build();

SYNCHRONOUS VS. ASYNCHRONOUS VS. OBSERVABLE

Methods can be declared for either synchronous or asynchronous execution.

A method with a return type will be executed synchronously.

@GET("/user/{id}/photo")

Photo getUserPhoto(@Path(“id”) int id);  
Asynchronous execution requires the last parameter of the method be a Callback.

@GET("/user/{id}/photo")

void getUserPhoto(@Path(“id”) int id, Callback cb);  
On Android, callbacks will be executed on the main thread. For desktop applications callbacks will happen on the same thread that executed the HTTP request.

Retrofit also integrates RxJava to support methods with a return type of rx.Observable

@GET("/user/{id}/photo")

Observable getUserPhoto(@Path(“id”) int id);  
Observable requests are subscribed asynchronously and observed on the same thread that executed the HTTP request. To observe on a different thread (e.g. Android’s main thread) call observeOn(Scheduler) on the returned Observable.

**RESPONSE OBJECT TYPE**

HTTP responses are automatically converted to a specified type using the RestAdapter’s converter which defaults to JSON. The desired type is declared as the method return type or using the Callback or Observable.

@GET("/users/list")
    List<User> userList();

@GET("/users/list")
    void userList(Callback<List<User>> cb);

@GET("/users/list")
    Observable<List<User>> userList();

For access to the raw HTTP response use the Response type.

@GET("/users/list")
    Response userList();

@GET("/users/list")
    void userList(Callback<Response> cb);

@GET("/users/list")
    Observable<Response> userList();

[_http_square.github.io_retrofit]: http://square.github.io/retrofit/
[http_square.github.io_okhttp]: http://square.github.io/okhttp/
[Android _ https_github.com_goodev_RetrofitDemo]: https://github.com/goodev/RetrofitDemo
[http_instructure.github.io_blog_2013_12_09_volley-vs-retrofit]: http://instructure.github.io/blog/2013/12/09/volley-vs-retrofit/
[tIdZkl3.png]: http://i.imgur.com/tIdZkl3.png