OkHttp3详解

OkHttp3 官网 & website

1.Http协议简介

客户端向服务器发送一个Request,服务端收到Request并进行一系列的处理，返回给客户端一个Response

Http状态码简介（code为三位数）
1xx（临时响应） 2xx （成功）3xx （重定向） 4xx（请求错误）5xx（服务器错误）

2.快速使用（AndroidStudio）

①添加依赖 compile ‘com.squareup.okhttp3:okhttp:3.8.1’
②添加网络权限
③GET请求

    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);            // 用完关闭资源            if (response.body()!=null){                response.body().close();            }         }     });

④Response里有这么两个方法

    // response.isSuccessful();是否连接成功 状态码2xx    // response.isRedirect();是否重定向 状态码3xx

⑤Post请求（form表单）

    OkHttpClient client = new OkHttpClient();    // post请求需要传入一个RequestBody对象    // 直接点进去RequestBody，通过查看源码发现RequestBody是个抽象类    // RequestBody右键-->Go To-->Implementation(s)    // 发现有两个具体实现类 FormBody(表单) MultiparBody(多种提交方式包括表单、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文件上传（表单形式上传文字和图片）

    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)    // 此处传"1"，可能会在后台生成图片名.1这种形式的文件    // 为了便于管理可以写成addFormDataPart("idcard_front_img","png",fileBody1)    // 传null可能会导致调用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,"上传成功");        }    });

⑧文件下载

    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源码与效果 点我下载源码