OkHttp3深刻了解之Interceptors

OKHttp官網上面介紹：攔截器是一種強大的機制，能夠監視，重寫和重試調用。這裏咱們主要對攔截器的網絡請求頭和數據請求的封裝。

• 網絡請求頭攔截器

  在Android應用中，咱們一般須要獲取用戶手機的IMEI值和其餘一些經常使用的參數，若是把他們封裝到請求頭裏面的話會很是的方便。
  既然是自定義攔截器，咱們首先確定要繼承OKHttp的攔截器，把這個自定義類設置成**final**類型的防止其餘類繼承。

這裏須要在父類的intercept(Chain chain)方法中進行操做。在方法裏面得
Request.Builder對象而後添加請求頭。
建立一個BaseParam 對象，對請求頭的參數進行封裝。

public final class HeaderInterceptorTest implements Interceptor {

    /**
     * 請求頭參數基礎參數
     */
    private static final String HEADER_BASE_PARAM = "baseParam";
    private static String BASE_PARAM;

    @Override
    public Response intercept(Chain chain) throws IOException {

        Request.Builder builder = chain.request().newBuilder();

        builder.addHeader(HEADER_BASE_PARAM, BASE_PARAM);
        return chain.proceed(builder.build());
    }

    public static void initBaseParam(Context context) {
        BaseParam baseParam = new BaseParam();
        String imei;
        String imsi;
        try {
            imei = DeviceInfoUtil.getIMEI(context);
        } catch (Exception e) {
            imei = null;
        }
        if (null == imei || imei.equals("")) {
            imei = DeviceInfoUtil.getDeviceID(context);
            imsi = DeviceInfoUtil.getDeviceID(context);
        } else {
            imei = DeviceInfoUtil.getIMEI(context);
            imsi = DeviceInfoUtil.getIMSI(context);
        }
        baseParam.setImei(imei);
        baseParam.setImsi(imsi);
        baseParam.setMac(DeviceInfoUtil.getWifiMAC(context));
        baseParam.setVersion(DeviceInfoUtil.getVersion(context));
        baseParam.setModel(DeviceInfoUtil.getModel());
        baseParam.setBrand(DeviceInfoUtil.getBrand());
        BASE_PARAM = new Gson().toJson(baseParam).toString();
    }

    private static class BaseParam {
        /**
         * imei :
         * imsi :
         * mac :
         * version :
         * model :
         * brand :
         * city :
         */
        private String imei;
        private String imsi;
        private String mac;
        private String version;
        private String model;
        private String brand;
        private String city;

        public String getImei() {
            return imei;
        }

        public void setImei(String imei) {
            this.imei = imei;
        }

        public String getImsi() {
            return imsi;
        }

        public void setImsi(String imsi) {
            this.imsi = imsi;
        }

        public String getMac() {
            return mac;
        }

        public void setMac(String mac) {
            this.mac = mac;
        }

        public String getVersion() {
            return version;
        }

        public void setVersion(String version) {
            this.version = version;
        }

        public String getModel() {
            return model;
        }

        public void setModel(String model) {
            this.model = model;
        }

        public String getBrand() {
            return brand;
        }

        public void setBrand(String brand) {
            this.brand = brand;
        }

        public String getCity() {
            return city;
        }

        public void setCity(String city) {
            this.city = city;
        }
    }
}

• 數據請求攔截器
  在進行數據請求的時候，通常都會定義一種固定的請求格式。在這裏咱們直接經過攔截器，將這個固定的格式定義好，這樣使用起來能夠統一管理。具體的使用方法其實和上面同樣。
  主要注意的是先獲得，請求時設置的請求體，而後讓請求的數據封裝到和後端設置的請求格式裏面。

public class HttpDataPackInterceptorTest implements Interceptor {

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();

        Request.Builder requestBuilder = chain.request().newBuilder();
        //請求數據處理
        if (request.url().toString().contains("uploads")) {
            //特殊接口的參數不須要處理的
        } else {
            //須要處理請求參數的
            if (request.body() instanceof FormBody) {
                FormBody.Builder newFormBody = new FormBody.Builder();
                //獲得請求時設置的請求體
                FormBody oldFormBody = (FormBody) request.body();
                Buffer buffer = new Buffer();
                oldFormBody.writeTo(buffer);
                String postParams = JsonUtils.getJsonStrFromPostParams(buffer.readString(Charset.forName("UTF-8")));
                String data = URLDecoder.decode(postParams, "UTF-8");
                if (TextUtils.isEmpty(data)) {
                    newFormBody.add("data", "");
                } else {
                    //將請求的數據封裝
                    newFormBody.add("data", data);
                }
                requestBuilder.method(request.method(), newFormBody.build());
            }
        }
        return chain.proceed(requestBuilder.build());
    }
}

• 代碼中調用
  在建立OkHttpClient 對象的時候，調用addInterceptor()方法添加倆個攔截器。

private OkHttpClient client;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_okhttp);
        HeaderInterceptorTest.initBaseParam(this);
        client= new OkHttpClient()
                .newBuilder()
                .addInterceptor(new HeaderInterceptorTest())
                .addInterceptor(new HttpDataPackInterceptorTest())
                .connectTimeout(60, TimeUnit.SECONDS)
                .writeTimeout(60, TimeUnit.SECONDS)
                .readTimeout(60, TimeUnit.SECONDS).build();
        okhttpAsyncPost();
    }

    private void okhttpAsyncPost(){
        RequestBody formBody = new FormBody.Builder()
                .add("page", "1")
                .add("count", "2")
                .add("type","video")
                .build();
        Request request = new Request.Builder()
                .url("https://api.apiopen.top/getJoke")
                .post(formBody)
                .build();

        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {

            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                Log.e("error","結果"+response.body().string());
                Log.e("error","方法"+response.request().toString());
                Log.e("error","請求頭"+response.request().headers().toString());
            }
        });
    }

打印的日誌

結果{"status":200,"msg":"OK","data":"{\"count\":\"2\",\"page\":\"1\",\"type\":\"video\"}"}
方法Request{method=POST, url=https://www.26uuun.com/list, tags={}}
請求頭baseParam: {"brand":"Xiaomi","city":"\u4e1c\u4eac","imei":"9fc70b16bf169075f556e6d67be9ef1a","imsi":"9fc70b16bf169075f556e6d67be9ef1a","mac":"02:00:00:00:00:00","model":"Mi Note 2","version":"1.0"}

OK，OKHttp3中Interceptors配置完成，小夥伴們，能夠設置本身不一樣需求的其餘的攔截器添加到請求中。
最近我會寫不少關於Android經常使用控件的使用，裏面都是一些頗有用的知識，若是你感受有用，請給我一個star,謝謝。代碼實例