//创建okHttpClient对象

        OkHttpClient mOkHttpClient = new OkHttpClient();

        //创建一个Request

        final Request request = new Request.Builder()

                .url("http://www.weather.com.cn/data/sk/101010100.html")

                .build();

        //new call

        Call call = mOkHttpClient.newCall(request);

        call.enqueue(new Callback() {

            @Override

            public void onFailure(Request request, IOException e) {

            }

            @Override

            public void onResponse(Response response) throws IOException {

                String htmlStr =  response.body().string();

            }

        });

        FormEncodingBuilder builder = new FormEncodingBuilder();

        builder.add("username","baobao");

        String url = "";

        Request request = new Request.Builder()

                .url(url)

                .post(builder.build())

                .build();

        OkHttpClient mOkHttpClient = new OkHttpClient();

        mOkHttpClient.newCall(request).enqueue(new Callback(){

            @Override

            public void onFailure(Request request, IOException e) {

            }

            @Override

            public void onResponse(Response response) throws IOException {

            }

        });