java 如何使用 HttpUrlConnection 在 POST 请求中发送请求参数
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How to send requestparameter in POST request using HttpUrlConnection
提问by deepak mishra
I need to send a POST request to a URL and send some request parameters. I am using HttpURLConnectionAPI for this. But my problem is I do not get any request parameter in the servlet. Although I see that the params are present in the request body, when I print the request body using request.getReader. Following is the client side code. Can any body please specify if this is correct way to send request parameters in POST request?
我需要向 URL 发送 POST 请求并发送一些请求参数。我为此使用了 HttpURLConnectionAPI。但我的问题是我没有在 servlet 中得到任何请求参数。虽然我看到请求正文中存在参数，但当我使用 request.getReader 打印请求正文时。以下是客户端代码。任何机构都可以指定这是否是在 POST 请求中发送请求参数的正确方法？
String urlstr = "http://serverAddress/webappname/TestServlet";
String params = "¶mname=paramvalue";
URL url = new URL(urlstr);
HttpURLConnection urlconn = (HttpURLConnection) url.openConnection();
urlconn.setDoInput(true);
urlconn.setDoOutput(true);
urlconn.setRequestMethod("POST");
urlconn.setRequestProperty("Content-Type", "text/xml");
urlconn.setRequestProperty("Content-Length", String.valueOf(params.getBytes().length));
urlconn.setRequestProperty("Content-Language", "en-US");
OutputStream os = urlconn.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
writer.write(params);
writer.close();
os.close();
回答by muruga
To be cleaner, you can encode to send the values.
为了更干净，您可以编码以发送值。
String data = URLEncoder.encode("key1", "UTF-8") + "=" + URLEncoder.encode("value1", "UTF-8");
data += "&" + URLEncoder.encode("key2", "UTF-8") + "=" + URLEncoder.encode("value2", "UTF-8");
URL url = new URL("http://yourserver.com/whatever");
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
wr.write(data);
回答by Femi
Like @Kal said, get rid of the leading &and don't bother with the BufferedWriter. This works for me:
就像@Kal 所说的那样，去掉前导&，不要理会 BufferedWriter。这对我有用：
byte[] bytes = parameters.getBytes("UTF-8");
httpUrlConnection.setRequestProperty("Content-Length", String.valueOf(bytes.length));
httpUrlConnection.setRequestMethod("POST");
httpUrlConnection.setDoOutput(true);
httpUrlConnection.connect();
outputStream = httpUrlConnection.getOutputStream();
outputStream.write(bytes);
