Android GET and POST Request

问题:

Can anyone point me to a good implementation of a way to send GET and POST Requests. They are alot of ways to do these, and i am looking for the best implementation. Secondly is there a generic way to send both these methods rather then using two different ways. After all the GET method merely has the params in the Query Strings, whereas the POST method uses the headers for the Params.

Thanks.

回答1:

You can use the HttpURLConnection class (in java.net) to send a POST or GET HTTP request. It is the same as any other application that might want to send an HTTP request. The code to send an Http Request would look like this:

import java.net.*;
import java.io.*;
public class SendPostRequest {
  public static void main(String[] args) throws MalformedURLException, IOException {
    URL reqURL = new URL("http://www.stackoverflow.com/"); //the URL we will send the request to
    HttpURLConnection request = (HttpURLConnection) (reqUrl.openConnection());
    String post = "this will be the post data that you will send"
    request.setDoOutput(true);
    request.addRequestProperty("Content-Length", Integer.toString(post.length)); //add the content length of the post data
    request.addRequestProperty("Content-Type", "application/x-www-form-urlencoded"); //add the content type of the request, most post data is of this type
    request.setMethod("POST");
    request.connect();
    OutputStreamWriter writer = new OutputStreamWriter(request.getOutputStream()); //we will write our request data here
    writer.write(post);
    writer.flush();
  }
}

A GET request will look a little bit different, but much of the code is the same. You don't have to worry about doing output with streams or specifying the content-length or content-type:

import java.net.*;
import java.io.*;

public class SendPostRequest {
  public static void main(String[] args) throws MalformedURLException, IOException {
    URL reqURL = new URL("http://www.stackoverflow.com/"); //the URL we will send the request to
    HttpURLConnection request = (HttpURLConnection) (reqUrl.openConnection());
    request.setMethod("GET");
    request.connect();

  }
}

回答2:

I prefer using dedicated class to do GET/POST and any HTTP connections or requests. Moreover I use HttpClient to execute these GET/POST methods.

Below is sample from my project. I needed thread-safe execution so there is ThreadSafeClientConnManager.

There is an example of using GET (fetchData) and POST (sendOrder)

As you can see execute is general method for executing HttpUriRequest - it can be POST or GET.

public final class ClientHttpClient {

private static DefaultHttpClient client;
private static CookieStore cookieStore;
private static HttpContext httpContext;

static {
    cookieStore = new BasicCookieStore();
    httpContext = new BasicHttpContext();
    httpContext.setAttribute(ClientContext.COOKIE_STORE, cookieStore);
    client = getThreadSafeClient();
    HttpParams params = new BasicHttpParams();
    HttpConnectionParams.setConnectionTimeout(params, AppConstants.CONNECTION_TIMEOUT);
    HttpConnectionParams.setSoTimeout(params, AppConstants.SOCKET_TIMEOUT);
    client.setParams(params);
}

private static DefaultHttpClient getThreadSafeClient() {
    DefaultHttpClient client = new DefaultHttpClient();
    ClientConnectionManager mgr = client.getConnectionManager();
    HttpParams params = client.getParams();
    client = new DefaultHttpClient(new ThreadSafeClientConnManager(params, mgr.getSchemeRegistry()),
            params);
    return client;
}

private ClientHttpClient() {
}

public static String execute(HttpUriRequest http) throws IOException {
    BufferedReader reader = null;
    try {
        StringBuilder builder = new StringBuilder();
        HttpResponse response = client.execute(http, httpContext);
        StatusLine statusLine = response.getStatusLine();
        int statusCode = statusLine.getStatusCode();
        HttpEntity entity = response.getEntity();
        InputStream content = entity.getContent();
        reader = new BufferedReader(new InputStreamReader(content, CHARSET));
        String line = null;
        while((line = reader.readLine()) != null) {
            builder.append(line);
        }

        if(statusCode != 200) {
            throw new IOException("statusCode=" + statusCode + ", " + http.getURI().toASCIIString()
                    + ", " + builder.toString());
        }

        return builder.toString();
    }
    finally {
        if(reader != null) {
            reader.close();
        }
    }
}


public static List<OverlayItem> fetchData(Info info) throws JSONException, IOException {
    List<OverlayItem> out = new LinkedList<OverlayItem>();
    HttpGet request = buildFetchHttp(info);
    String json = execute(request);
    if(json.trim().length() <= 2) {
        return out;
    }
    try {
        JSONObject responseJSON = new JSONObject(json);
        if(responseJSON.has("auth_error")) {
            throw new IOException("auth_error");
        }
    }
    catch(JSONException e) {
        //ok there was no error, because response is JSONArray - not JSONObject
    }

    JSONArray jsonArray = new JSONArray(json);
    for(int i = 0; i < jsonArray.length(); i++) {
        JSONObject chunk = jsonArray.getJSONObject(i);
        ChunkParser parser = new ChunkParser(chunk);
        if(!parser.hasErrors()) {
            out.add(parser.parse());
        }
    }
    return out;
}

private static HttpGet buildFetchHttp(Info info) throws UnsupportedEncodingException {
    StringBuilder builder = new StringBuilder();
    builder.append(FETCH_TAXIS_URL);
    builder.append("?minLat=" + URLEncoder.encode("" + mapBounds.getMinLatitude(), ENCODING));
    builder.append("&maxLat=" + URLEncoder.encode("" + mapBounds.getMaxLatitude(), ENCODING));
    builder.append("&minLon=" + URLEncoder.encode("" + mapBounds.getMinLongitude(), ENCODING));
    builder.append("&maxLon=" + URLEncoder.encode("" + mapBounds.getMaxLongitude(), ENCODING));
    HttpGet get = new HttpGet(builder.toString());
    return get;
}

public static int sendOrder(OrderInfo info) throws IOException {
    HttpPost post = new HttpPost(SEND_ORDER_URL);
    List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
    nameValuePairs.add(new BasicNameValuePair("id", "" + info.getTaxi().getId()));
    nameValuePairs.add(new BasicNameValuePair("address", info.getAddressText()));
    nameValuePairs.add(new BasicNameValuePair("name", info.getName()));
    nameValuePairs.add(new BasicNameValuePair("surname", info.getSurname()));
    nameValuePairs.add(new BasicNameValuePair("phone", info.getPhoneNumber()));
    nameValuePairs.add(new BasicNameValuePair("passengers", "" + info.getPassengers()));
    nameValuePairs.add(new BasicNameValuePair("additionalDetails", info.getAdditionalDetails()));
    nameValuePairs.add(new BasicNameValuePair("lat", "" + info.getOrderLocation().getLatitudeE6()));
    nameValuePairs.add(new BasicNameValuePair("lon", "" + info.getOrderLocation().getLongitudeE6()));
    post.setEntity(new UrlEncodedFormEntity(nameValuePairs));

    String response = execute(post);
    if(response == null || response.trim().length() == 0) {
        throw new IOException("sendOrder_response_empty");
    }

    try {
        JSONObject json = new JSONObject(response);
        int orderId = json.getInt("orderId");
        return orderId;
    }
    catch(JSONException e) {
        throw new IOException("sendOrder_parsing: " + response);
    }
}

EDIT

The execute method is public because sometimes I use custom (or dynamic) GET/POST requests.

If you have URL object you can pass to execute method:

HttpGet request = new HttpGet(url.toString());
execute(request);

回答3:

As you said: the GET-Parameters are in the URL - So you can use a loadUrl() on your Webview to send them.

[..].loadUrl("http://www.example.com/data.php?param1=value1&param2=value2&...");

回答4:

The developer training docs have a good example on GET requests. You're responsible for adding the query parameters to the URL.

Post is similar, but as you said, quite different. The HttpConnectionURLConnection class can do both, and it's easy to just set the post body with an output stream.

回答5:

 protected String doInBackground(String... strings) {
        String response = null;
        String data = null;
        try {
            data = URLEncoder.encode("CustomerEmail", "UTF-8")
                    + "=" + URLEncoder.encode(username, "UTF-8");

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        String url = Constant.URL_FORGOT_PASSWORD;// this is url 
        response = ServiceHandler.postData(url,data);
        if (response.equals("")){
            return response;
        }else {
            return response;
        }

    }


public static String postData(String urlpath,String data){

    String text = "";
    BufferedReader reader=null;
    try
    {
        // Defined URL  where to send data
        URL url = new URL(urlpath);

        // Send POST data request
        URLConnection conn = url.openConnection();
        conn.setDoOutput(true);
        OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
        wr.write( data );
        wr.flush();

        // Get the server response
        reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        StringBuilder sb = new StringBuilder();
        String line = null;

        // Read Server Response
        while((line = reader.readLine()) != null)
        {
            sb.append(line + "\n");
        }
        text = sb.toString();
        return text;
    }
    catch(Exception ex)
    {
    }
    finally
    {
        try
        {
            reader.close();
        }
        catch(Exception ex) {}
    }
    return text;
}

回答6:

private RequestListener listener;
private int requestId;
private HashMap<String, String> reqParams;
private File file;
private String fileName;
private RequestMethod reqMethod;
private String url;
private Context context;
private boolean isProgressVisible = false;
private MyProgressDialog progressDialog;

public NetworkClient(Context context, int requestId, RequestListener listener,
                     String url, HashMap<String, String> reqParams, RequestMethod reqMethod,
                     boolean isProgressVisible) {

    this.listener = listener;
    this.requestId = requestId;
    this.reqParams = reqParams;
    this.reqMethod = reqMethod;
    this.url = url;
    this.context = context;
    this.isProgressVisible = isProgressVisible;
}

public NetworkClient(Context context, int requestId, RequestListener listener,
                     String url, HashMap<String, String> reqParams, File file, String fileName, RequestMethod reqMethod,
                     boolean isProgressVisible) {

    this.listener = listener;
    this.requestId = requestId;
    this.reqParams = reqParams;
    this.file = file;
    this.fileName = fileName;
    this.reqMethod = reqMethod;
    this.url = url;
    this.context = context;
    this.isProgressVisible = isProgressVisible;
}

@Override
protected void onPreExecute() {
    super.onPreExecute();
    if (isProgressVisible) {
        showProgressDialog();
    }
}

@Override
protected String doInBackground(Void... params) {

    try {

        if (Utils.isInternetAvailable(context)) {

            OkHttpClient.Builder clientBuilder = new OkHttpClient.Builder();
            clientBuilder.connectTimeout(10, TimeUnit.SECONDS);
            clientBuilder.writeTimeout(10, TimeUnit.SECONDS);
            clientBuilder.readTimeout(20, TimeUnit.SECONDS);
            OkHttpClient client = clientBuilder.build();

            if (reqMethod == RequestMethod.GET) {

                Request.Builder reqBuilder = new Request.Builder();
                reqBuilder.url(url);
                Request request = reqBuilder.build();
                Response response = client.newCall(request).execute();
                String message = response.message();
                String res = response.body().string();

                JSONObject jObj = new JSONObject();
                jObj.put("statusCode", 1);
                jObj.put("response", message);
                return jObj.toString();

            } else if (reqMethod == RequestMethod.POST) {


                FormBody.Builder formBuilder = new FormBody.Builder();

                RequestBody body = formBuilder.build();

                Request.Builder reqBuilder = new Request.Builder();
                reqBuilder.url(url);
                reqBuilder.post(body);
                Request request = reqBuilder.build();
                Response response = client.newCall(request).execute();

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

                JSONObject jObj = new JSONObject();
                jObj.put("statusCode", 1);
                jObj.put("response", res);
                return jObj.toString();

            } else if (reqMethod == RequestMethod.MULTIPART) {

                MediaType MEDIA_TYPE = fileName.endsWith("png") ?
                        MediaType.parse("image/png") : MediaType.parse("image/jpeg");

                MultipartBody.Builder multipartBuilder = new MultipartBody.Builder();
                multipartBuilder.setType(MultipartBody.FORM);

                multipartBuilder.addFormDataPart("file", fileName, RequestBody.create(MEDIA_TYPE, file));

                RequestBody body = multipartBuilder.build();

                Request.Builder reqBuilder = new Request.Builder();
                reqBuilder.url(url);
                reqBuilder.post(body);
                Request request = reqBuilder.build();
                Response response = client.newCall(request).execute();
                String res = response.body().string();


                JSONObject jObj = new JSONObject();
                jObj.put("statusCode", 1);
                jObj.put("response", res);
                return jObj.toString();
            }

        } else {

            JSONObject jObj = new JSONObject();
            jObj.put("statusCode", 0);
            jObj.put("response", context.getString(R.string.no_internet));
            return jObj.toString();
        }
    } catch (final Exception e) {
        e.printStackTrace();
        JSONObject jObj = new JSONObject();
        try {
            jObj.put("statusCode", 0);
            jObj.put("response", e.toString());
        } catch (Exception e1) {
            e1.printStackTrace();
        }
        return jObj.toString();
    }

    return null;
}

@Override
protected void onPostExecute(String result) {
    super.onPostExecute(result);
    try {
        JSONObject jObj = new JSONObject(result);
        if (jObj.getInt("statusCode") == 1) {
            listener.onSuccess(requestId, jObj.getString("response"));
        } else {
            listener.onError(requestId, jObj.getString("response"));
        }
    } catch (Exception e) {
        listener.onError(requestId, result);
    } finally {
        dismissProgressDialog();
    }
}


private void showProgressDialog() {
    progressDialog = new MyProgressDialog(context);
}

private void dismissProgressDialog() {
    if (progressDialog != null && progressDialog.isShowing()) {
        progressDialog.dismiss();
        progressDialog = null;
    }
}


private static NetworkManager instance = null;
private Set<RequestListener> arrRequestListeners = null;
private int requestId;
public boolean isProgressVisible = false;

private NetworkManager() {
    arrRequestListeners = new HashSet<>();
    arrRequestListeners = Collections.synchronizedSet(arrRequestListeners);
}

public static NetworkManager getInstance() {
    if (instance == null)
        instance = new NetworkManager();
    return instance;
}

public synchronized int addRequest(final HashMap<String, String> params, Context context, RequestMethod reqMethod, String apiMethod) {

    try {

        String url = Constants.WEBSERVICE_URL + apiMethod;
        requestId = UniqueNumberUtils.getInstance().getUniqueId();

        NetworkClient networkClient = new NetworkClient(context, requestId, this, url, params, reqMethod, isProgressVisible);
        networkClient.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);

    } catch (Exception e) {
        onError(requestId, e.toString() + e.getMessage());
    }

    return requestId;
}



public synchronized int addMultipartRequest(final HashMap<String,String> params, File file, String fileName, Context context, RequestMethod reqMethod, String apiMethod) {

    try {

        String url = Constants.WEBSERVICE_URL + apiMethod;
        requestId = UniqueNumberUtils.getInstance().getUniqueId();

        NetworkClient networkClient = new NetworkClient(context, requestId, this, url, params, file, fileName, reqMethod, isProgressVisible);
        networkClient.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);

    } catch (Exception e) {
        onError(requestId, e.toString() + e.getMessage());
    }

    return requestId;
}

public void isProgressBarVisible(boolean isProgressVisible) {
    this.isProgressVisible = isProgressVisible;
}

public void setListener(RequestListener listener) {
    try {
        if (listener != null && !arrRequestListeners.contains(listener)) {
            arrRequestListeners.add(listener);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

@Override
public void onSuccess(int id, String response) {

    if (arrRequestListeners != null && arrRequestListeners.size() > 0) {
        for (RequestListener listener : arrRequestListeners) {
            if (listener != null)
                listener.onSuccess(id, response);
        }
    }
}

@Override
public void onError(int id, String message) {
    try {
        if (Looper.myLooper() == null) {
            Looper.prepare();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    if (arrRequestListeners != null && arrRequestListeners.size() > 0) {
        for (final RequestListener listener : arrRequestListeners) {
            if (listener != null) {
                listener.onError(id, message);
            }
        }
    }
}

public void removeListener(RequestListener listener) {
    try {
        arrRequestListeners.remove(listener);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Create RequestListner intreface

public void onSuccess(int id, String response);

public void onError(int id, String message);

Get Unique Number

private static UniqueNumberUtils INSTANCE = new UniqueNumberUtils();

private AtomicInteger seq;

private UniqueNumberUtils() {
    seq = new AtomicInteger(0);
}

public int getUniqueId() {
    return seq.incrementAndGet();
}

public static UniqueNumberUtils getInstance() {
    return INSTANCE;
}