5 . for Android = >

org.apache.http类和AndroidHttpClient类在Android 5.1中已弃用。这些类不再被维护，你应该尽快将任何使用这些api的应用程序代码迁移到URLConnection类。

https://developer.android.com/about/versions/android-5.1.html#http

考虑使用HttpUrlConnection共享我的代码

public String  performPostCall(String requestURL,
        HashMap<String, String> postDataParams) {

    URL url;
    String response = "";
    try {
        url = new URL(requestURL);

        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setReadTimeout(15000);
        conn.setConnectTimeout(15000);
        conn.setRequestMethod("GET");
        conn.setDoInput(true);
        conn.setDoOutput(true);


        OutputStream os = conn.getOutputStream();
        BufferedWriter writer = new BufferedWriter(
                new OutputStreamWriter(os, "UTF-8"));
        writer.write(getPostDataString(postDataParams));

        writer.flush();
        writer.close();
        os.close();
        int responseCode=conn.getResponseCode();

        if (responseCode == HttpsURLConnection.HTTP_OK) {
            String line;
            BufferedReader br=new BufferedReader(new InputStreamReader(conn.getInputStream()));
            while ((line=br.readLine()) != null) {
                response+=line;
            }
        }
        else {
            response="";    

        }
    } catch (Exception e) {
        e.printStackTrace();
    }

    return response;
}

...

private String getPostDataString(HashMap<String, String> params) throws UnsupportedEncodingException{
        StringBuilder result = new StringBuilder();
        boolean first = true;
        for(Map.Entry<String, String> entry : params.entrySet()){
            if (first)
                first = false;
            else
                result.append("&");

            result.append(URLEncoder.encode(entry.getKey(), "UTF-8"));
            result.append("=");
            result.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
        }

        return result.toString();
    }

你也可以张贴方法:

conn.setRequestMethod("POST");

更新21/02/2016

对于post request with json，请看这个例子:

public class Empty extends
        AsyncTask<Void, Void, Boolean> {

    String urlString = "http://www.yoursite.com/";

    private final String TAG = "post json example";
    private Context context;

    private int advertisementId;

    public Empty(Context contex, int advertisementId) {

        this.context = contex;
        this.advertisementId = advertisementId;
    }

    @Override
    protected void onPreExecute() {
        Log.e(TAG, "1 - RequestVoteTask is about to start...");

    }

    @Override
    protected Boolean doInBackground(Void... params) {
        boolean status = false;

        String response = "";
        Log.e(TAG, "2 - pre Request to response...");

        try {
            response = performPostCall(urlString, new HashMap<String, String>() {

                        private static final long serialVersionUID = 1L;

                        {
                            put("Accept", "application/json");
                            put("Content-Type", "application/json");
                        }
                    });
            Log.e(TAG, "3 - give Response...");
            Log.e(TAG, "4 " + response.toString());
        } catch (Exception e) {
            // displayLoding(false);

            Log.e(TAG, "Error ...");
        }
        Log.e(TAG, "5 - after Response...");

        if (!response.equalsIgnoreCase("")) {
            try {
                Log.e(TAG, "6 - response !empty...");
                //
                JSONObject jRoot = new JSONObject(response);
                JSONObject d = jRoot.getJSONObject("d");

                int ResultType = d.getInt("ResultType");
                Log.e("ResultType", ResultType + "");

                if (ResultType == 1) {

                    status = true;

                }

            } catch (JSONException e) {
                // displayLoding(false);
                // e.printStackTrace();
                Log.e(TAG, "Error " + e.getMessage());
            } finally {

            }
        } else {
            Log.e(TAG, "6 - response is empty...");

            status = false;
        }

        return status;
    }

    @Override
    protected void onPostExecute(Boolean result) {
        //
        Log.e(TAG, "7 - onPostExecute ...");

        if (result) {
            Log.e(TAG, "8 - Update UI ...");

            // setUpdateUI(adv);
        } else {
            Log.e(TAG, "8 - Finish ...");

            // displayLoding(false);
            // finish();
        }

    }

    public String performPostCall(String requestURL,
                                  HashMap<String, String> postDataParams) {

        URL url;
        String response = "";
        try {
            url = new URL(requestURL);

            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setReadTimeout(context.getResources().getInteger(
                    R.integer.maximum_timeout_to_server));
            conn.setConnectTimeout(context.getResources().getInteger(
                    R.integer.maximum_timeout_to_server));
            conn.setRequestMethod("POST");
            conn.setDoInput(true);
            conn.setDoOutput(true);

            conn.setRequestProperty("Content-Type", "application/json");

            Log.e(TAG, "11 - url : " + requestURL);

            /*
             * JSON
             */

            JSONObject root = new JSONObject();
            //
            String token = Static.getPrefsToken(context);

            root.put("securityInfo", Static.getSecurityInfo(context));
            root.put("advertisementId", advertisementId);

            Log.e(TAG, "12 - root : " + root.toString());

            String str = root.toString();
            byte[] outputBytes = str.getBytes("UTF-8");
            OutputStream os = conn.getOutputStream();
            os.write(outputBytes);

            int responseCode = conn.getResponseCode();

            Log.e(TAG, "13 - responseCode : " + responseCode);

            if (responseCode == HttpsURLConnection.HTTP_OK) {
                Log.e(TAG, "14 - HTTP_OK");

                String line;
                BufferedReader br = new BufferedReader(new InputStreamReader(
                        conn.getInputStream()));
                while ((line = br.readLine()) != null) {
                    response += line;
                }
            } else {
                Log.e(TAG, "14 - False - HTTP_OK");
                response = "";
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return response;
    }
}

更新24/08/2016

使用一些最好的库，例如:

改造 凌空抽射

因为:

避免使用HttpUrlConnection和HttpClient

在较低的API级别上(主要是在Gingerbread和Froyo上)，httppurlconnection和HttpClient还远远不够完美

并且避免AsyncTask 他们要快得多 他们会缓存所有东西

自从Honeycomb (API 11)引入以来，强制在不同于主线程的单独线程上执行网络操作

在新版本的Android中，你必须把所有的web I/O请求放到一个新的线程中。AsyncTask最适合小请求。

注(2020年10月):以下答案中使用的AsyncTask已在Android API级别30中弃用。有关更新的示例，请参考官方文档或本博客文章

更新(2017年6月)答案，适用于Android 6.0+。感谢@Rohit Suthar， @Tamis Bolvari和@sudhiskr的评论。

    public class CallAPI extends AsyncTask<String, String, String> {
    
        public CallAPI(){
            //set context variables if required
        }
    
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }
    
         @Override
         protected String doInBackground(String... params) {
            String urlString = params[0]; // URL to call
            String data = params[1]; //data to post
            OutputStream out = null;

            try {
                URL url = new URL(urlString);
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                out = new BufferedOutputStream(urlConnection.getOutputStream());

                BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
                writer.write(data);
                writer.flush();
                writer.close();
                out.close();

                urlConnection.connect();
            } catch (Exception e) {
                System.out.println(e.getMessage());
            }
        }
    }

引用:

https://developer.android.com/reference/java/net/HttpURLConnection.html 如何使用NameValuePair使用POST添加参数到HttpURLConnection

原答案(2010年5月)

注意:此解决方案已过时。它只能在5.1版本以下的安卓设备上运行。Android 6.0及以上版本不包括本回答中使用的Apache http客户端。

来自Apache Commons的Http Client是可行的。它已经包含在android中。下面是一个简单的例子，说明如何使用它来执行HTTP Post。

public void postData() {
    // Create a new HttpClient and Post Header
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("http://www.yoursite.com/script.php");

    try {
        // Add your data
        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
        nameValuePairs.add(new BasicNameValuePair("id", "12345"));
        nameValuePairs.add(new BasicNameValuePair("stringdata", "Hi"));
        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

        // Execute HTTP Post Request
        HttpResponse response = httpclient.execute(httppost);
        
    } catch (ClientProtocolException e) {
        // TODO Auto-generated catch block
    } catch (IOException e) {
        // TODO Auto-generated catch block
    }
} 

你可以使用URLConnection setDoOutput(true)， getOutputStream()(用于发送数据)，和getInputStream()(用于接收)。Sun在这方面有一个例子。

这是一个如何在不使用外部Apache库的情况下POST多部分数据的例子:

byte[] buffer = getBuffer();

if(buffer.length > 0) {
   String lineEnd = "\r\n"; 
   String twoHyphens = "--"; 
   String boundary =  "RQdzAAihJq7Xp1kjraqf"; 

   ByteArrayOutputStream baos = new ByteArrayOutputStream();
   DataOutputStream dos = new DataOutputStream(baos);

   // Send parameter #1
   dos.writeBytes(twoHyphens + boundary + lineEnd); 
   dos.writeBytes("Content-Disposition: form-data; name=\"param1\"" + lineEnd);
   dos.writeBytes("Content-Type: text/plain; charset=US-ASCII" + lineEnd);
   dos.writeBytes("Content-Transfer-Encoding: 8bit" + lineEnd);
   dos.writeBytes(lineEnd);
   dos.writeBytes(myStringData + lineEnd);

   // Send parameter #2
   //dos.writeBytes(twoHyphens + boundary + lineEnd); 
   //dos.writeBytes("Content-Disposition: form-data; name=\"param2\"" + lineEnd + lineEnd);
   //dos.writeBytes("foo2" + lineEnd);

   // Send a binary file
   dos.writeBytes(twoHyphens + boundary + lineEnd); 
   dos.writeBytes("Content-Disposition: form-data; name=\"param3\";filename=\"test_file.dat\"" + lineEnd); 
   dos.writeBytes("Content-Type: application/octet-stream" + lineEnd);
   dos.writeBytes("Content-Transfer-Encoding: binary" + lineEnd);
   dos.writeBytes(lineEnd); 
   dos.write(buffer);
   dos.writeBytes(lineEnd); 
   dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd); 
   dos.flush(); 
   dos.close();

   ByteArrayInputStream content = new ByteArrayInputStream(baos.toByteArray());
   BasicHttpEntity entity = new BasicHttpEntity();
   entity.setContent(content);

   HttpPost httpPost = new HttpPost(myURL);
   httpPost.addHeader("Connection", "Keep-Alive");
   httpPost.addHeader("Content-Type", "multipart/form-data; boundary="+boundary);

   //MultipartEntity entity = new MultipartEntity();
   //entity.addPart("param3", new ByteArrayBody(buffer, "test_file.dat"));
   //entity.addPart("param1", new StringBody(myStringData));

   httpPost.setEntity(entity);

   /*
   String httpData = "";
   ByteArrayOutputStream baos1 = new ByteArrayOutputStream();
   entity.writeTo(baos1);
   httpData = baos1.toString("UTF-8");
   */

   /*
   Header[] hdrs = httpPost.getAllHeaders();
   for(Header hdr: hdrs) {
     httpData += hdr.getName() + " | " + hdr.getValue() + " |_| ";
   }
   */

   //Log.e(TAG, "httpPost data: " + httpData);
   response = httpClient.execute(httpPost);
}

方法将数据作为HTTP请求发布，

public static InputStream callPostService(String Url,
        List<NameValuePair> data) {
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost(Url);
    try {
        httppost.setEntity(new UrlEncodedFormEntity(data));
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        return entity.getContent();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
}