按照上面的建议使用凌空射击。添加以下到构建。gradle(模块:app)

implementation 'com.android.volley:volley:1.1.1'

在AndroidManifest.xml中添加以下内容:

<uses-permission android:name="android.permission.INTERNET" />

并添加以下活动代码:

public void httpCall(String url) {

    RequestQueue queue = Volley.newRequestQueue(this);

    StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    // enjoy your response
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    // enjoy your error status
                }
    });

    queue.add(stringRequest);
}

它取代了http客户端，非常简单。

按照上面的建议使用凌空射击。添加以下到构建。gradle(模块:app)

implementation 'com.android.volley:volley:1.1.1'

在AndroidManifest.xml中添加以下内容:

<uses-permission android:name="android.permission.INTERNET" />

并添加以下活动代码:

public void httpCall(String url) {

    RequestQueue queue = Volley.newRequestQueue(this);

    StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    // enjoy your response
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    // enjoy your error status
                }
    });

    queue.add(stringRequest);
}

它取代了http客户端，非常简单。

注意:与Android捆绑的Apache HTTP客户端现在已弃用，转而支持HttpURLConnection。请参阅Android开发者博客了解更多细节。

添加<uses-permission android:name="android.permission. "INTERNET" />到您的舱单。

然后你会像这样检索一个网页:

URL url = new URL("http://www.android.com/");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
     InputStream in = new BufferedInputStream(urlConnection.getInputStream());
     readStream(in);
}
finally {
     urlConnection.disconnect();
}

我还建议在一个单独的线程上运行它:

class RequestTask extends AsyncTask<String, String, String>{

@Override
protected String doInBackground(String... uri) {
    String responseString = null;
    try {
        URL url = new URL(myurl);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        if(conn.getResponseCode() == HttpsURLConnection.HTTP_OK){
            // Do normal input or output stream reading
        }
        else {
            response = "FAILED"; // See documentation for more info on response handling
        }
    } catch (ClientProtocolException e) {
        //TODO Handle problems..
    } catch (IOException e) {
        //TODO Handle problems..
    }
    return responseString;
}

@Override
protected void onPostExecute(String result) {
    super.onPostExecute(result);
    //Do anything with response..
}
}

有关响应处理和POST请求的更多信息，请参阅文档。

private String getToServer(String service) throws IOException {
    HttpGet httpget = new HttpGet(service);
    ResponseHandler<String> responseHandler = new BasicResponseHandler();
    return new DefaultHttpClient().execute(httpget, responseHandler);

}

问候

我做了这个webservice请求URL，使用一个Gson库:

客户:

public EstabelecimentoList getListaEstabelecimentoPorPromocao(){

        EstabelecimentoList estabelecimentoList  = new EstabelecimentoList();
        try{
            URL url = new URL("http://" +  Conexao.getSERVIDOR()+ "/cardapio.online/rest/recursos/busca_estabelecimento_promocao_android");
            HttpURLConnection con = (HttpURLConnection) url.openConnection();

            if (con.getResponseCode() != 200) {
                    throw new RuntimeException("HTTP error code : "+ con.getResponseCode());
            }

            BufferedReader br = new BufferedReader(new InputStreamReader((con.getInputStream())));
            estabelecimentoList = new Gson().fromJson(br, EstabelecimentoList.class);
            con.disconnect();

        } catch (IOException e) {
            e.printStackTrace();
        }
        return estabelecimentoList;
}

最简单的方法是使用名为Volley的Android库

Volley offers the following benefits: Automatic scheduling of network requests. Multiple concurrent network connections. Transparent disk and memory response caching with standard HTTP cache coherence. Support for request prioritization. Cancellation request API. You can cancel a single request, or you can set blocks or scopes of requests to cancel. Ease of customization, for example, for retry and backoff. Strong ordering that makes it easy to correctly populate your UI with data fetched asynchronously from the network. Debugging and tracing tools.

你可以发送一个http/https请求，简单如下:

        // Instantiate the RequestQueue.
        RequestQueue queue = Volley.newRequestQueue(this);
        String url ="http://www.yourapi.com";
        JsonObjectRequest request = new JsonObjectRequest(url, null,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    if (null != response) {
                         try {
                             //handle your response
                         } catch (JSONException e) {
                             e.printStackTrace();
                         }
                    }
                }
            }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError error) {

            }
        });
        queue.add(request);

在这种情况下，你不必考虑“运行在后台”或“使用缓存”自己，因为所有这些都已经完成了Volley。