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前言

Retrofit 和RxJava已经出来很久了，很多前辈写了很多不错的文章，在此不得不感谢这些前辈无私奉献的开源精神，能让我们站在巨人的肩膀上望得更远。

Retrofit：Retrofit是Square 公司开发的一款针对Android 网络请求的框架。

RxJava：RxJava 是一个链式调用的异步框架。

RxJava在 GitHub 主页上的自我详情是 “a library for composing asynchronous and event-based programs using observable sequences for the Java VM”（一个在 Java VM 上使用可观测的序列来组成异步的、基于事件的程序的库）。这就是 RxJava ，概括得非常精准。

一言以辟之，就是让异步操作变得非常简单。

各自职责：Retrofit 负责请求的数据和请求的结果，使用接口的方式呈现，OkHttp 负责请求的过程，RxJava 负责异步，各种线程之间的切换。

RxJava的使用参考–>给 Android 开发者的 RxJava 详解
Retrofit的使用参考–>Android Retrofit 2.0使用

本文内容是基于Retrofit + RxJava做的少量优雅的封装。参考了很多文章加入了少量自己的了解，请多指教。

先引入依赖

build.gradle

    // Okhttp库    implementation 'com.squareup.okhttp3:okhttp:3.11.0'    implementation 'com.squareup.okhttp3:logging-interceptor:3.8.1'    // Retrofit库    implementation 'com.squareup.retrofit2:retrofit:2.1.0'    implementation 'com.squareup.retrofit2:adapter-rxjava2:2.2.0'    //RxJava    implementation 'io.reactivex.rxjava2:rxjava:2.0.1'    implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'

简单使用

1、先写一个接口Service

interface APIService {    @GET("user/login" )    Call<UserInfo> login(@Query("username") String username,@Query("password")String password);}

2、获取Call执行网络请求

Retrofit retrofit = new Retrofit.Builder()                .addConverterFactory(GsonConverterFactory.create())                .baseUrl(BASE_URL)                .build();        APIService service = retrofit.create(APIService.class);        Call<UserInfo> call = service.login("张晓宇", "is sb");        call.enqueue(new Callback<UserInfo>() {            @Override            public void onResponse(Call<UserInfo> call, Response<UserInfo> response) {                //请求成功            }            @Override            public void onFailure(Call<UserInfo> call, Throwable t) {                //请求失败            }        });

以上就是Retrofit的简单使用。但是实际项目中，我们一定不会这么写，这样写完全不符合我们写代码的优雅性和简洁性。所以，我们要对它进行优雅的封装。

Retrofit+RxJava优雅的封装

1、请求实体类与返回实体类的封装

BaseRequestEntity.java

public class BaseRequestEntity <T>{    private HeaderEntity header;    private T data;    public HeaderEntity getHeader() {        return header;    }    public void setHeader(HeaderEntity header) {        this.header = header;    }    public T getData() {        return data;    }    public void setData(T data) {        this.data = data;    }}

BaseResponseEntity.java

public class BaseResponseEntity<T> {    private int errorCode;    private String errorMsg;    private T data;    public int getErrorCode() {        return errorCode;    }    public void setErrorCode(int errorCode) {        this.errorCode = errorCode;    }    public String getErrorMsg() {        return errorMsg;    }    public void setErrorMsg(String errorMsg) {        this.errorMsg = errorMsg;    }    public T getData() {        return data;    }    public void setData(T data) {        this.data = data;    }}

2、请求接口服务类封装

ObservableAPI.java

/** * 接口服务 **/public interface ObservableAPI {    /**     * 登录     */    @POST(URL.URL_LOGIN)    Observable<BaseResponseEntity<LoginResponseEntity>> login(@Body BaseRequestEntity<LoginRequestEntity> requestEntity);}

3、ObservableManager封装（请求接口传参封装）

ObservableManager.java

public class ObservableManager {    private static class SingletonHolder {        static final ObservableManager INSTANCE = new ObservableManager();    }    public static ObservableManager getInstance() {        return ObservableManager.SingletonHolder.INSTANCE;    }    /**     * login     */    public BaseRequestEntity<LoginRequestEntityl> getLoginRequestEntity() {        BaseRequestEntity<LoginRequestEntity> requestModel = new BaseRequestEntity<>();        requestModel.setHeader(HeaderUtils.setHeaderModel());        LoginRequestEntity loginRequestModel = new LoginRequestEntity();        requestModel.setData(loginRequestModel);        return requestModel;    }}

4、Retrofit封装

RetrofitHandler.java

public class RetrofitHandler {    private static Retrofit mRetrofit;    private static OkHttpClient mOkHttpClient;    private static RetrofitHandler mRetrofitHandler;    private static ObservableAPI mObservableAPI;    private RetrofitHandler() {        initRetrofit();    }    public static synchronized RetrofitHandler getInstance() {        if (mRetrofitHandler == null) {            synchronized (RetrofitHandler.class) {                if (mRetrofitHandler == null) {                    mRetrofitHandler = new RetrofitHandler();                }            }        }        return mRetrofitHandler;    }    /**     * 获取 Retrofit     */    private void initRetrofit() {        initOkHttpClient();        mRetrofit = new Retrofit.Builder()                .baseUrl(URL.BASE_URL)                //JSON转换器,使用Gson来转换                .addConverterFactory(GsonConverterFactory.create())                //RxJava适配器                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())                .client(mOkHttpClient)                .build();        mObservableAPI = mRetrofit.create(ObservableAPI.class);    }    /**     * 单例模式获取 OkHttpClient     */    private static void initOkHttpClient() {        if (mOkHttpClient == null) {            synchronized (RetrofitHandler.class) {                if (mOkHttpClient == null) {                    // 指定缓存路径,缓存大小100Mb                    Cache cache = new Cache(new File(HttpConfig.DIR_CACHE_FILE, "HttpCache"),                            1024 * 1024 * 100);                    mOkHttpClient = new OkHttpClient.Builder()                            //设置连接超时时间                            .connectTimeout(HttpConfig.HTTP_TIME_OUT_TIME, TimeUnit.SECONDS)                            //设置读取超时时间                            .readTimeout(HttpConfig.HTTP_TIME_OUT_TIME, TimeUnit.SECONDS)                            //设置写入超时时间                            .writeTimeout(HttpConfig.HTTP_TIME_OUT_TIME, TimeUnit.SECONDS)                            //默认重试一次                            .retryOnConnectionFailure(true)                            //增加请求头阻拦器                            .addInterceptor(InterceptorHelper.getHeaderInterceptor())                            //增加日志阻拦器                            .addInterceptor(InterceptorHelper.getLogInterceptor())                            //增加缓存阻拦器                            .addInterceptor(InterceptorHelper.getCacheInterceptor())                            //增加重试阻拦器                            .addInterceptor(InterceptorHelper.getRetryInterceptor())                            // 信任Https,忽略Https证书验证                            // https认证,假如要使用https且为自己设置证书 可以去掉这两行注释，并自行配制证书。                            .sslSocketFactory(SSLSocketTrust.getSSLSocketFactory())                            .hostnameVerifier(SSLSocketTrust.getHostnameVerifier())                            //缓存                            .cache(cache)                            .build();                }            }        }    }    /**     * 对外提供调用 API的接口     *     * @return     */    public ObservableAPI getAPIService() {        return mObservableAPI;    }}

5、阻拦器封装（请求头阻拦器、日志阻拦器、缓存阻拦器、重试阻拦器等）

InterceptorHelper.java

/** * @author wy * @description 阻拦器工具类 */public class InterceptorHelper {    public static String TAG = "Interceptor";    /**     * 日志阻拦器     */    public static HttpLoggingInterceptor getLogInterceptor() {        return new HttpLoggingInterceptor(new HttpLoggingInterceptor.Logger() {            @Override            public void log(String message) {                Log.w(TAG, "LogInterceptor---------: " + message);            }        }).setLevel(HttpLoggingInterceptor.Level.BODY);//设置打印数据的级别    }    /**     * 缓存阻拦器     *     * @return     */    public static Interceptor getCacheInterceptor() {        return new Interceptor() {            @Override            public Response intercept(Chain chain) throws IOException {                Request request = chain.request();                //CONTEXT不能为空                if (!NetworkUtils.isConnected(PalApplication.getInstance().getApplicationContext())) {                    int maxStale = 4 * 7 * 24 * 60; // 离线时缓存保存4周,单位:秒                    CacheControl tempCacheControl = new CacheControl.Builder()                            .onlyIfCached()                            .maxStale(maxStale, TimeUnit.SECONDS)                            .build();                    request = request.newBuilder()                            .cacheControl(tempCacheControl)                            .build();                }                return chain.proceed(request);            }        };    }    /**     * 重试阻拦器     *     * @return     */    public static Interceptor getRetryInterceptor() {        return new Interceptor() {            @Override            public Response intercept(Chain chain) throws IOException {                int maxRetry = 10;//最大重试次数                int retryNum = 5;//如果设置为3次重试的话，则最大可能请求4次（默认1次+3次重试）                Request request = chain.request();                Response response = chain.proceed(request);                while (!response.isSuccessful() && retryNum < maxRetry) {                    retryNum++;                    response = chain.proceed(request);                }                return response;            }        };    }    /**     * 请求头阻拦器     *     * @return     */    public static Interceptor getHeaderInterceptor() {        return new Interceptor() {            @Override            public Response intercept(Chain chain) throws IOException {                //在这里你可以做少量想做的事,比方token失效时,重新获取token                //或者者增加header等等                Request originalRequest = chain.request();                if (null == originalRequest.body()) {                    return chain.proceed(originalRequest);                }                Request compressedRequest = originalRequest.newBuilder()                        .header("Content-Encoding", "gzip")                        .header("User-Agent", "OkHttp Headers.java")                        .addHeader("Accept", "application/json; q=0.5")                        .addHeader("Accept", "application/vnd.github.v3+json")                        .addHeader("Accept-Encoding", "identity")//                    .addHeader(Constants.WEB_TOKEN, webi_token)                        .build();                Response proceed = chain.proceed(compressedRequest);                return proceed;            }        };    }}

6、BaseObserver封装（请求失败、网络异常、接口错误、加载窗口等解决）

BaseObserver.java

public abstract class BaseObserver<T> implements Observer<BaseResponseEntity<T>> {    protected Context mContext;    public BaseObserver() {    }    public BaseObserver(Context cxt) {        this.mContext = cxt;    }    @Override    public void onSubscribe(Disposable d) {        onRequestStart();    }    @Override    public void onNext(BaseResponseEntity<T> tBaseEntity) {        onRequestEnd();        String message_common = "Oops, something went wrong. Please try again.";        if (tBaseEntity.getErrorCode()==0) {//成功            try {                onSuccess(tBaseEntity);            } catch (Exception e) {                e.printStackTrace();            }        } else {            try {                if (!CommonUtils.isEmptyOrNull(tBaseEntity.getErrorMsg())) {                    onFailure(tBaseEntity.getErrorMsg());                } else {                    onFailure(message_common);                }            } catch (Exception e) {                e.printStackTrace();            }        }    }    @Override    public void onError(Throwable e) {        onRequestEnd();        String message_common = "Oops, something went wrong. Please try again.";        String msg_timeout = "Oops, connection timeout, please try again later";        try {            if (e instanceof ConnectException                    || e instanceof TimeoutException                    || e instanceof NetworkErrorException                    || e instanceof UnknownHostException) {                onFailure(msg_timeout);            } else {                onFailure(message_common);            }        } catch (Exception e1) {            e1.printStackTrace();        }    }    @Override    public void onComplete() {    }    /**     * 返回成功     *     * @param tBaseEntity     */    protected abstract void onSuccess(BaseResponseEntity<T> tBaseEntity);    /**     * 返回失败     *     * @param errorMessage     */    protected abstract void onFailure(String errorMessage);    /**     * 请求开始     */    protected void onRequestStart() {        showProgressDialog();    }    /**     * 请求结束     */    protected void onRequestEnd() {        closeProgressDialog();    }    /**     * 加载弹窗     */    public void showProgressDialog() {    }    /**     * 关闭加载弹窗     */    public void closeProgressDialog() {    }}

7、调度类封装

RxTransformerHelper.java

/** * 调度类 */public class RxTransformerHelper {    public static <T> ObservableTransformer<T, T> observableIO2Main(final Context context) {        return new ObservableTransformer<T, T>() {            @Override            public ObservableSource<T> apply(Observable<T> upstream) {                return upstream.subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread());            }        };    }}

8、使用方式

private void login() {        RetrofitHandler.getInstance().getAPIService()                .login(ObservableManager.getInstance().getLoginRequestEntity())                .compose(RxTransformerHelper.<BaseResponseEntity<LoginResponseModel>>observableIO2Main(this))                .subscribe(new BaseObserver<LoginResponseModel>() {                    @Override                    protected void onSuccess(BaseResponseEntity<LoginResponseModel> responseEntity) {                        showSuccessDialog("Success");                    }                    @Override                    protected void onFailure(String errorMessage) {                        showErrorDialog(errorMessage);                    }                });    }