尝试使用HTTPurlconnection将数据发布到网站，但不断出错

Question

try {
        URL url = new URL(html);

        HttpURLConnection connection =  (HttpURLConnection) url.openConnection();

        String urlParameters = "symbol="+symbol+"&Submit=Submit";
        connection.setRequestMethod("POST");
        connection.setRequestProperty("USER-AGENT","Mozilla/5.0");
        connection.setRequestProperty("ACCEPT-LANGUAGE","en-US,en;0.5");
        connection.setDoOutput(true);

        DataOutputStream dstream = new DataOutputStream(connection.getOutputStream());

        dstream.writeBytes(urlParameters);
        dstream.flush();
        dstream.close();

        int responseCode = connection.getResponseCode();
        String output = "Request Url"+ url;
        output += System.getProperty("line.separator") + "Request Parameters" + urlParameters;
        output += System.getProperty("line.separator") + "Response Code" + responseCode;

        BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        String line ="";
        StringBuilder responseOutput = new StringBuilder();

        while((line = br.readLine()) != null){
            responseOutput.append(line);
        }
        br.close();

        output += System.getProperty("lin.separator") + responseOutput.toString();

        textView.setText(output);
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

我想做的是提交一个我在网站上制作的表格，该表格可以接收张贴数据。 表格如下：

       
输入符号编号：       范例（0201382D）

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我正在尝试使用该应用程序提交表单...然后重定向到另一个显示学生标记的网址。