java如何提交网页

Question

URL url = new URL("http://ip/cgi-bin/");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
PrintWriter out = new PrintWriter(connection.getOutputStream());
String username = "username="+URLEncoder.encode("user", "UTF-8");
String password = "password="+URLEncoder.encode("passwd", "UTF-8");
out.println(username+"&"+password);
out.close();
BufferedReader in= new BufferedReader(new InputStreamReader  (connection.getInputStream()));
String line;
line=in.readLine()