为什么我不能在 Retrofit 上添加标头来拦截请求 OkHttp？答案

【问题标题】：Why I can't add header to interceptor requeset OkHttp on Retrofit?为什么我不能在 Retrofit 上添加标头来拦截请求 OkHttp？
【发布时间】：2017-08-23 02:08:55
【问题描述】：

能否请您指出我在代码中的错误，我无法将标题“授权”添加到拦截器。当我发出请求时，它会抛出错误 retrofit2.adapter.rxjava.HttpException: HTTP 401 Unauthorized 。但是当我为每个请求添加 Header 令牌时

@Header("Authorization") String token

然后就可以了。

这是我的代码：

 protected Retrofit retrofit;
protected OkHttpClient client;
protected T api;
protected UserCredential userCredential;

public RestClient(Class<T> type) {
    if (client == null) {
        synchronized (OkHttpClient.class) {
            client = new OkHttpClient();
            client.newBuilder().addInterceptor(chain -> {
                Request original = chain.request();
                Request.Builder builder = original.newBuilder();
                if (GrabDoiApplication.getInstance().getCurrentCredentials() != null) {
                    String token = GrabDoiApplication.getInstance().getCurrentCredentials().getToken();
                    if (token != null) {
                        builder.addHeader("Authorization", token);
                    }
                }
                builder.method(original.method(), original.body());

                return chain.proceed(builder.build());
            }).build();

            if (retrofit == null) {
                synchronized (Retrofit.class) {
                    Retrofit.Builder retrofitBuilder = new Retrofit.Builder()
                            .baseUrl(Constants.GRABDOI_SERVER_URL)
                            .client(client)
                            .addConverterFactory(GsonConverterFactory.create())
                            .addCallAdapterFactory(RxJavaCallAdapterFactory.create());
                    retrofit = retrofitBuilder.build();
                }
            }
        }
    }
    api = retrofit.create(type);
}

【问题讨论】：

标签： android rest retrofit interceptor

【解决方案1】：

你可以尝试把对静态方法的访问放到拦截器的主体之外：

    public RestClient(Class<T> type) {
    if (retrofit != null) {
        return;
    }
    synchronized (OkHttpClient.class) {
        client = new OkHttpClient();
        OkHttpClient.Builder builder = client.newBuilder();
        final String token;
        if (GrabDoiApplication.getInstance().getCurrentCredentials() != null &&
                (token = GrabDoiApplication.getInstance().getCurrentCredentials().getToken()) != null) {
            builder.addInterceptor(chain -> {
                Request.Builder builder = chain.request().newBuilder();
                builder.addHeader("Authorization", token);
                builder.method(original.method(), original.body());
                return chain.proceed(builder.build());
            });
        }
        client = builder.build();

        synchronized (Retrofit.class) {
            Retrofit.Builder retrofitBuilder = new Retrofit.Builder()
                    .baseUrl(Constants.GRABDOI_SERVER_URL)
                    .client(client)
                    .addConverterFactory(GsonConverterFactory.create())
                    .addCallAdapterFactory(RxJavaCallAdapterFactory.create());
            retrofit = retrofitBuilder.build();
        }
    }


    api = retrofit.create(type);
}

【讨论】：