OkHttp3 官網 & website

1.Http協議簡介

客戶端向服務器發送一個Request,服務端收到Request并進行一系列的處理，返回給客戶端一個Response

Http狀態碼簡介（code為三位數）
1xx（臨時響應） 2xx （成功）3xx （重定向） 4xx（請求錯誤）5xx（服務器錯誤）

2.快速使用（AndroidStudio）

①添加依賴 compile ‘com.squareup.okhttp3:okhttp:3.8.1’
②添加網絡權限
③GET請求

    OkHttpClient client = new OkHttpClient();
    Request request = new Request.Builder().url(url).build();
    client.newCall(request).enqueue(new Callback() {
        @Override
        public void onFailure(Call call, IOException e) {
            Log.e(TAG, "onFailure: "+ e.getLocalizedMessage());
        }

        @Override
        public void onResponse(Call call, Response response) throws IOException {

            String result = response.body().string();
            Log.e(TAG, "onResponse: "+result);


            // 用完關閉資源
            if (response.body()!=null){
                response.body().close();
            }
         }
     });

④Response里有這么兩個方法

    // response.isSuccessful();是否連接成功 狀態碼2xx
    // response.isRedirect();是否重定向 狀態碼3xx

⑤Post請求（form表單）

    OkHttpClient client = new OkHttpClient();

    // post請求需要傳入一個RequestBody對象
    // 直接點進去RequestBody，通過查看源碼發現RequestBody是個抽象類
    // RequestBody右鍵-->Go To-->Implementation(s)
    // 發現有兩個具體實現類 FormBody(表單) MultiparBody(多種提交方式包括表單、文件等)
    RequestBody body;

    body = new FormBody.Builder().add("phone","12345678900").build();

    Request request = new Request.Builder().url(postPath).post(body).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 {

    });

⑥Post(json形式)

    OkHttpClient client = new OkHttpClient();

    // json字符串  {"phone":"1234678900"}
    String jsonParams = new Gson().toJson(new Phone("1234678900"));

    RequestBody body = RequestBody.create(MediaType.parse("application/json"),jsonParams);

    Request request = new Request.Builder().url(postPath).post(body).build();
    client.newCall(request).enqueue(new Callback() {

        @Override
        public void onFailure(Call call, IOException e) {

        }

        @Override
        }
    });

⑦文件上傳（表單形式上傳文字和圖片）

    OkHttpClient client = new OkHttpClient();

    String basePath = Environment.getExternalStorageDirectory().getAbsolutePath();

    RequestBody fileBody1 = RequestBody.create(MediaType.parse("image/png"),new File(basePath+"img1.png"));
    RequestBody fileBody2 = RequestBody.create(MediaType.parse("image/png"),new File(basePath+"img2.png"));

    // .addFormDataPart("idcard_front_img","1",fileBody1)
    // 此處傳"1"，可能會在后臺生成圖片名.1這種形式的文件
    // 為了便于管理可以寫成addFormDataPart("idcard_front_img","png",fileBody1)
    // 傳null可能會導致調用fail方法
    RequestBody body = new MultipartBody.Builder()
        .setType(MultipartBody.FORM)
        .addFormDataPart("idcard_no","130233199560509xxxx")
        .addFormDataPart("idcard_front_img","1",fileBody1)
        .addFormDataPart("idcard_behind_img","2",fileBody2)
        .build();

    Request request = new Request.Builder().url(imgPostPath).post(body).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.d(TAG,"上傳成功");
        }
    });

⑧文件下載

    OkHttpClient client = new OkHttpClient();
    Request request = new Request.Builder().url(downLoadPath).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 {

            InputStream is = null;
            FileOutputStream fos = null;

            is = response.body().byteStream();
            fos = new FileOutputStream(new File(Environment.getExternalStorageDirectory().getAbsolutePath(),"xxx.apk"));

            byte[] b = new byte[1024];
            int len = 0;

            while ((len = is.read(b))!=-1){
                fos.write(b,0,len);
                fos.flush();
            }

            is.close();
            fos.close();
        }
    });

⑨源碼與效果 點我下載源碼