Java – 通过POST方法轻松发送HTTP参数

我成功地使用此代码通过GET方法发送带有一些参数的HTTP请求

 void sendRequest(String request) { // ie: request = "http://example.com/index.php?param1=a&param2=b&param3=c"; URL url = new URL(request); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); connection.setDoOutput(true); connection.setInstanceFollowRedirects(false); connection.setRequestMethod("GET"); connection.setRequestProperty("Content-Type", "text/plain"); connection.setRequestProperty("charset", "utf-8"); connection.connect(); } 

现在我可能需要通过POST方法发送参数（即param1，param2，param3），因为它们非常长。 我想在该方法中添加一个额外的参数（即String httpMethod）。

如何通过GET或POST尽可能少地更改上面的代码？

我希望改变

 connection.setRequestMethod("GET"); 

至

 connection.setRequestMethod("POST"); 

本来可以做到的，但参数仍然是通过GET方法发送的。

HttpURLConnection有没有任何方法可以提供帮助？ 有没有有用的Java构造？

任何帮助将非常感谢。

Answer 1

在GET请求中，参数作为URL的一部分发送。

在POST请求中，参数在标头之后作为请求的主体发送。

要使用HttpURLConnection执行POST，您需要在打开连接后将参数写入连接。

这段代码应该让你入门：

 String urlParameters = "param1=a&param2=b&param3=c"; byte[] postData = urlParameters.getBytes( StandardCharsets.UTF_8 ); int postDataLength = postData.length; String request = "http://example.com/index.php"; URL url = new URL( request ); HttpURLConnection conn= (HttpURLConnection) url.openConnection(); conn.setDoOutput( true ); conn.setInstanceFollowRedirects( false ); conn.setRequestMethod( "POST" ); conn.setRequestProperty( "Content-Type", "application/x-www-form-urlencoded"); conn.setRequestProperty( "charset", "utf-8"); conn.setRequestProperty( "Content-Length", Integer.toString( postDataLength )); conn.setUseCaches( false ); try( DataOutputStream wr = new DataOutputStream( conn.getOutputStream())) { wr.write( postData ); } 

Answer 2

下面是一个提交表单然后将结果页面转储到System.out的简单示例。 当然，适当地更改URL和POST参数：

 import java.io.*; import java.net.*; import java.util.*; class Test { public static void main(String[] args) throws Exception { URL url = new URL("http://example.net/new-message.php"); Map params = new LinkedHashMap<>(); params.put("name", "Freddie the Fish"); params.put("email", "[e-mail]"); params.put("reply_to_thread", 10394); params.put("message", "Shark attacks in Botany Bay have gotten out of control. We need more defensive dolphins to protect the schools here, but Mayor Porpoise is too busy stuffing his snout with lobsters. He's so shellfish."); StringBuilder postData = new StringBuilder(); for (Map.Entry param : params.entrySet()) { if (postData.length() != 0) postData.append('&'); postData.append(URLEncoder.encode(param.getKey(), "UTF-8")); postData.append('='); postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8")); } byte[] postDataBytes = postData.toString().getBytes("UTF-8"); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod("POST"); conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); conn.setRequestProperty("Content-Length", String.valueOf(postDataBytes.length)); conn.setDoOutput(true); conn.getOutputStream().write(postDataBytes); Reader in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8")); for (int c; (c = in.read()) >= 0;) System.out.print((char)c); } } 

---

如果您希望将结果作为String而不是直接打印出来，请执行以下操作：

  StringBuilder sb = new StringBuilder(); for (int c; (c = in.read()) >= 0;) sb.append((char)c); String response = sb.toString(); 

Answer 3

我无法得到艾伦的例子来实际发帖，所以我最终得到了这个：

 String urlParameters = "param1=a&param2=b&param3=c"; URL url = new URL("http://example.com/index.php"); URLConnection conn = url.openConnection(); conn.setDoOutput(true); OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream()); writer.write(urlParameters); writer.flush(); String line; BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream())); while ((line = reader.readLine()) != null) { System.out.println(line); } writer.close(); reader.close(); 

Answer 4

我发现HttpURLConnection真的很麻烦。 而且你必须编写很多样板，容易出错的代码。 我需要一个用于Android项目的轻量级包装器，并提供了一个可以使用的库： DavidWebb 。

上面的例子可以这样写：

 Webb webb = Webb.create(); webb.post("http://example.com/index.php") .param("param1", "a") .param("param2", "b") .param("param3", "c") .ensureSuccess() .asVoid(); 

您可以在提供的链接上找到替代库的列表。

Answer 5

我看到其他一些答案已经给出了替代方案，我个人认为直觉上你做的是正确的事情;）。 对不起，在devoxx，几个发言者一直在咆哮这种事情。

这就是为什么我个人使用Apache的HTTPClient / HttpCore库来完成这类工作，我发现他们的API比Java的本机HTTP支持更容易使用。 YMMV当然！

Answer 6

 import java.net.*; public class Demo{ public static void main(){ String data = "data=Hello+World!"; URL url = new URL("http://localhost:8084/WebListenerServer/webListener"); HttpURLConnection con = (HttpURLConnection) url.openConnection(); con.setRequestMethod("POST"); con.setDoOutput(true); con.getOutputStream().write(data.getBytes("UTF-8")); con.getInputStream(); } } 

Answer 7

我已阅读上述答案并创建了一个实用程序类来简化HTTP请求。 我希望它会对你有所帮助。

方法调用

  // send params with Hash Map HashMap params = new HashMap(); params.put("email","[e-mail]"); params.put("password","12345"); //server url String url = "http://www.example.com"; // static class "HttpUtility" with static method "newRequest(url,method,callback)" HttpUtility.newRequest(url,HttpUtility.METHOD_POST,params, new HttpUtility.Callback() { @Override public void OnSuccess(String response) { // on success System.out.println("Server OnSuccess response="+response); } @Override public void OnError(int status_code, String message) { // on error System.out.println("Server OnError status_code="+status_code+" message="+message); } }); 

实用类

 import java.io.*; import java.net.*; import java.util.HashMap; import java.util.Map; import static java.net.HttpURLConnection.HTTP_OK; public class HttpUtility { public static final int METHOD_GET = 0; // METHOD GET public static final int METHOD_POST = 1; // METHOD POST // Callback interface public interface Callback { // abstract methods public void OnSuccess(String response); public void OnError(int status_code, String message); } // static method public static void newRequest(String web_url, int method, HashMap < String, String > params, Callback callback) { // thread for handling async task new Thread(new Runnable() { @Override public void run() { try { String url = web_url; // write GET params,append with url if (method == METHOD_GET && params != null) { for (Map.Entry < String, String > item: params.entrySet()) { String key = URLEncoder.encode(item.getKey(), "UTF-8"); String value = URLEncoder.encode(item.getValue(), "UTF-8"); if (!url.contains("?")) { url += "?" + key + "=" + value; } else { url += "&" + key + "=" + value; } } } HttpURLConnection urlConnection = (HttpURLConnection) new URL(url).openConnection(); urlConnection.setDoOutput(true); // write POST params urlConnection.setUseCaches(false); urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); // handle url encoded form data urlConnection.setRequestProperty("charset", "utf-8"); if (method == METHOD_GET) { urlConnection.setRequestMethod("GET"); } else if (method == METHOD_POST) { urlConnection.setRequestMethod("POST"); } //write POST data if (method == METHOD_POST && params != null) { StringBuilder postData = new StringBuilder(); for (Map.Entry < String, String > item: params.entrySet()) { if (postData.length() != 0) postData.append('&'); postData.append(URLEncoder.encode(item.getKey(), "UTF-8")); postData.append('='); postData.append(URLEncoder.encode(String.valueOf(item.getValue()), "UTF-8")); } byte[] postDataBytes = postData.toString().getBytes("UTF-8"); urlConnection.setRequestProperty("Content-Length", String.valueOf(postDataBytes.length)); urlConnection.getOutputStream().write(postDataBytes); } // server response code int responseCode = urlConnection.getResponseCode(); if (responseCode == HTTP_OK && callback != null) { BufferedReader reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream())); StringBuilder response = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { response.append(line); } // callback success callback.OnSuccess(response.toString()); reader.close(); // close BufferReader } else if (callback != null) { // callback error callback.OnError(responseCode, urlConnection.getResponseMessage()); } urlConnection.disconnect(); // disconnect connection } catch (IOException e) { e.printStackTrace(); if (callback != null) { // callback error callback.OnError(500, e.getLocalizedMessage()); } } } }).start(); // start thread } } 

Answer 8

我遇到过同样的问题。 我想通过POST发送数据。 我使用了以下代码：

  URL url = new URL("http://example.com/getval.php"); Map params = new LinkedHashMap<>(); params.put("param1", param1); params.put("param2", param2); StringBuilder postData = new StringBuilder(); for (Map.Entry param : params.entrySet()) { if (postData.length() != 0) postData.append('&'); postData.append(URLEncoder.encode(param.getKey(), "UTF-8")); postData.append('='); postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8")); } String urlParameters = postData.toString(); URLConnection conn = url.openConnection(); conn.setDoOutput(true); OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream()); writer.write(urlParameters); writer.flush(); String result = ""; String line; BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream())); while ((line = reader.readLine()) != null) { result += line; } writer.close(); reader.close() System.out.println(result); 

我使用Jsoup进行解析：

  Document doc = Jsoup.parseBodyFragment(value); Iterator opts = doc.select("option").iterator(); for (;opts.hasNext();) { Element item = opts.next(); if (item.hasAttr("value")) { System.out.println(item.attr("value")); } } 

Answer 9

试试这种模式：

 public static PricesResponse getResponse(EventRequestRaw request) { // String urlParameters = "param1=a&param2=b&param3=c"; String urlParameters = Piping.serialize(request); HttpURLConnection conn = RestClient.getPOSTConnection(endPoint, urlParameters); PricesResponse response = null; try { // POST OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream()); writer.write(urlParameters); writer.flush(); // RESPONSE BufferedReader reader = new BufferedReader(new InputStreamReader((conn.getInputStream()), StandardCharsets.UTF_8)); String json = Buffering.getString(reader); response = (PricesResponse) Piping.deserialize(json, PricesResponse.class); writer.close(); reader.close(); } catch (Exception e) { e.printStackTrace(); } conn.disconnect(); System.out.println("PricesClient: " + response.toString()); return response; } public static HttpURLConnection getPOSTConnection(String endPoint, String urlParameters) { return RestClient.getConnection(endPoint, "POST", urlParameters); } public static HttpURLConnection getConnection(String endPoint, String method, String urlParameters) { System.out.println("ENDPOINT " + endPoint + " METHOD " + method); HttpURLConnection conn = null; try { URL url = new URL(endPoint); conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod(method); conn.setDoOutput(true); conn.setRequestProperty("Content-Type", "text/plain"); } catch (IOException e) { e.printStackTrace(); } return conn; } 

Answer 10

在这里我发送了jsonobject作为参数// jsonobject = {“name”：“lucifer”，“pass”：“abc”} // serverUrl =“ http://192.168.100.12/testing ”//host=192.168.100.12

  public static String getJson(String serverUrl,String host,String jsonobject){ StringBuilder sb = new StringBuilder(); String http = serverUrl; HttpURLConnection urlConnection = null; try { URL url = new URL(http); urlConnection = (HttpURLConnection) url.openConnection(); urlConnection.setDoOutput(true); urlConnection.setRequestMethod("POST"); urlConnection.setUseCaches(false); urlConnection.setConnectTimeout(50000); urlConnection.setReadTimeout(50000); urlConnection.setRequestProperty("Content-Type", "application/json"); urlConnection.setRequestProperty("Host", host); urlConnection.connect(); //You Can also Create JSONObject here OutputStreamWriter out = new OutputStreamWriter(urlConnection.getOutputStream()); out.write(jsonobject);// here i sent the parameter out.close(); int HttpResult = urlConnection.getResponseCode(); if (HttpResult == HttpURLConnection.HTTP_OK) { BufferedReader br = new BufferedReader(new InputStreamReader( urlConnection.getInputStream(), "utf-8")); String line = null; while ((line = br.readLine()) != null) { sb.append(line + "\n"); } br.close(); Log.e("new Test", "" + sb.toString()); return sb.toString(); } else { Log.e(" ", "" + urlConnection.getResponseMessage()); } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (JSONException e) { e.printStackTrace(); } finally { if (urlConnection != null) urlConnection.disconnect(); } return null; } 

Answer 11

我高度推荐建立在apache http api上的http-request 。

对于您的情况，您可以看到示例：

 private static final HttpRequest HTTP_REQUEST = HttpRequestBuilder.createPost("http://example.com/index.php", String.class) .responseDeserializer(ResponseDeserializer.ignorableDeserializer()) .build(); public void sendRequest(String request){ String parameters = request.split("\\?")[1]; ResponseHandler responseHandler = HTTP_REQUEST.executeWithQuery(parameters); System.out.println(responseHandler.getStatusCode()); System.out.println(responseHandler.get()); //prints response body } 

如果您对响应机构不感兴趣

 private static final HttpRequest HTTP_REQUEST = HttpRequestBuilder.createPost("http://example.com/index.php").build(); public void sendRequest(String request){ ResponseHandler responseHandler = HTTP_REQUEST.executeWithQuery(parameters); } 

对于带有http请求的一般发送请求 ：阅读文档并查看我的答案JAVA中使用JSON字符串的 HTTP POST请求 ， 使用Java中的JSON 发送HTTP POST请求

Answer 12

您好请使用此类来改进您的post方法

 public static JSONObject doPostRequest(HashMap data, String url) { try { RequestBody requestBody; MultipartBuilder mBuilder = new MultipartBuilder().type(MultipartBuilder.FORM); if (data != null) { for (String key : data.keySet()) { String value = data.get(key); Utility.printLog("Key Values", key + "-----------------" + value); mBuilder.addFormDataPart(key, value); } } else { mBuilder.addFormDataPart("temp", "temp"); } requestBody = mBuilder.build(); Request request = new Request.Builder() .url(url) .post(requestBody) .build(); OkHttpClient client = new OkHttpClient(); Response response = client.newCall(request).execute(); String responseBody = response.body().string(); Utility.printLog("URL", url); Utility.printLog("Response", responseBody); return new JSONObject(responseBody); } catch (UnknownHostException | UnsupportedEncodingException e) { JSONObject jsonObject=new JSONObject(); try { jsonObject.put("status","false"); jsonObject.put("message",e.getLocalizedMessage()); } catch (JSONException e1) { e1.printStackTrace(); } Log.e(TAG, "Error: " + e.getLocalizedMessage()); } catch (Exception e) { e.printStackTrace(); JSONObject jsonObject=new JSONObject(); try { jsonObject.put("status","false"); jsonObject.put("message",e.getLocalizedMessage()); } catch (JSONException e1) { e1.printStackTrace(); } Log.e(TAG, "Other Error: " + e.getLocalizedMessage()); } return null; } 

Answer 13

我接受了Boann的回答并用它来创建一个更灵活的查询字符串构建器，它支持列表和数组，就像php的http_build_query方法一样：

 public static byte[] httpBuildQueryString(Map postsData) throws UnsupportedEncodingException { StringBuilder postData = new StringBuilder(); for (Map.Entry param : postsData.entrySet()) { if (postData.length() != 0) postData.append('&'); Object value = param.getValue(); String key = param.getKey(); if(value instanceof Object[] || value instanceof List) { int size = value instanceof Object[] ? ((Object[])value).length : ((List)value).size(); for(int i = 0; i < size; i++) { Object val = value instanceof Object[] ? ((Object[])value)[i] : ((List)value).get(i); if(i>0) postData.append('&'); postData.append(URLEncoder.encode(key + "[" + i + "]", "UTF-8")); postData.append('='); postData.append(URLEncoder.encode(String.valueOf(val), "UTF-8")); } } else { postData.append(URLEncoder.encode(key, "UTF-8")); postData.append('='); postData.append(URLEncoder.encode(String.valueOf(value), "UTF-8")); } } return postData.toString().getBytes("UTF-8"); } 

Answer 14

GET和POST方法设置如下…… api调用的两种类型1）get（）和2）post（）。 get（）方法从api json数组中获取值以获取值＆post（）方法在url中的数据文章中使用并得到响应。

  public class HttpClientForExample { private final String USER_AGENT = "Mozilla/5.0"; public static void main(String[] args) throws Exception { HttpClientExample http = new HttpClientExample(); System.out.println("Testing 1 - Send Http GET request"); http.sendGet(); System.out.println("\nTesting 2 - Send Http POST request"); http.sendPost(); } // HTTP GET request private void sendGet() throws Exception { String url = "http://www.google.com/search?q=developer"; HttpClient client = new DefaultHttpClient(); HttpGet request = new HttpGet(url); // add request header request.addHeader("User-Agent", USER_AGENT); HttpResponse response = client.execute(request); System.out.println("\nSending 'GET' request to URL : " + url); System.out.println("Response Code : " + response.getStatusLine().getStatusCode()); BufferedReader rd = new BufferedReader( new InputStreamReader(response.getEntity().getContent())); StringBuffer result = new StringBuffer(); String line = ""; while ((line = rd.readLine()) != null) { result.append(line); } System.out.println(result.toString()); } // HTTP POST request private void sendPost() throws Exception { String url = "https://selfsolve.apple.com/wcResults.do"; HttpClient client = new DefaultHttpClient(); HttpPost post = new HttpPost(url); // add header post.setHeader("User-Agent", USER_AGENT); List urlParameters = new ArrayList(); urlParameters.add(new BasicNameValuePair("sn", "C02G8416DRJM")); urlParameters.add(new BasicNameValuePair("cn", "")); urlParameters.add(new BasicNameValuePair("locale", "")); urlParameters.add(new BasicNameValuePair("caller", "")); urlParameters.add(new BasicNameValuePair("num", "12345")); post.setEntity(new UrlEncodedFormEntity(urlParameters)); HttpResponse response = client.execute(post); System.out.println("\nSending 'POST' request to URL : " + url); System.out.println("Post parameters : " + post.getEntity()); System.out.println("Response Code : " + response.getStatusLine().getStatusCode()); BufferedReader rd = new BufferedReader( new InputStreamReader(response.getEntity().getContent())); StringBuffer result = new StringBuffer(); String line = ""; while ((line = rd.readLine()) != null) { result.append(line); } System.out.println(result.toString()); } } 

Answer 15

看来你还必须调用connection.getOutputStream() “至少一次”（以及setDoOutput(true) ），以便将其视为POST。

所以最低要求的代码是：

  URL url = new URL(urlString); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); //connection.setRequestMethod("POST"); this doesn't seem to do anything at all..so not useful connection.setDoOutput(true); // set it to POST...not enough by itself however, also need the getOutputStream call... connection.connect(); connection.getOutputStream().close(); 

你甚至可以在urlString中使用“GET”样式参数。 虽然这可能会让事情变得混乱。

您也可以使用NameValuePair 。