java我试图将google recaptcha与spring mvc集成，但GreCaptCharResponse总是返回false。这里有一些代码

Question

验证ReCAPTCHA类

public class VerifyRecaptcha {

    public static final String url = "https://www.google.com/recaptcha/api/siteverify";
    public static final String secret = "6LcIicUUAAAAAOeuLpcAVmE53PYtPphreUT9FuVg";
    private final static String USER_AGENT = "Mozilla/5.0";


    public static boolean verify(String gRecaptchaResponse) throws IOException {
        if (gRecaptchaResponse == null || "".equals(gRecaptchaResponse)) {
            return false;
        }


        try {
            URL obj = new URL(url);
            HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();

            // add request header

            con.setRequestMethod("POST");
            con.setRequestProperty("User-Agent", USER_AGENT);
            con.setRequestProperty("Accept-Language", "en-US,en:q=0.5");

            String postParams = "secret" + secret + "&response=" + gRecaptchaResponse;

            // Send post request

            con.setDoOutput(true);
            DataOutputStream wr = new DataOutputStream(con.getOutputStream());
            wr.writeBytes(postParams);
            wr.flush();
            wr.close();

            int responseCode = con.getResponseCode();
            System.out.println("\nSending 'POST' request to URL : " + url);
            System.out.println("Post parameters :" + postParams);
            System.out.println("Response Code :" + responseCode);

            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));

            String inputLine;
            StringBuffer response = new StringBuffer();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);

            }
            in.close();

            // print result
            System.out.println("test "+ response.toString());

            // parse JSON response and return 'success' value
            JsonReader jsonReader = Json.createReader(new StringReader(response.toString()));
            JsonObject jsonObject = jsonReader.readObject();
            jsonReader.close();

            return jsonObject.getBoolean("success");
        } 
        catch (Exception e) {
            e.printStackTrace();
            return false;
        }

    }
}

LoginController类

@Controller
public class LoginController {

    /*
     * ========================================================================
     * Constants
     * ========================================================================
     */
    /** Attribute name msg */
    private static final String ATTRIBUTE_NAME_MSG = "msg";
    /** Attribute name error */
    private static final String ATTRIBUTE_NAME_ERROR = "error";
    /** Attribute value Login detail */
    private static final String ATTRIBUTE_VAL_MSG_LOGIN_DETAIL = "Please Enter Your Login Details";
    /** Attribute value invalid user name and password */
    private static final String ATTRIBUTE_VAL_INVALID = "Invalid username and password";
    /** Attribute value enter user name and password */
    private static final String ATTRIBUTE_VAL_ENTER_USR_PWD = "Please enter username and password.";
    /** Attribute value verify Recaptcha */
    private static final String ATTRIBUTE_VAL_ENTER_RECAPTCHA = "Please verify captcha.";
    /** Path to file connection DataBase */
    private static final String RESOURCE_PATH = "e7bankaccountprinting/config/mybatis-config.xml";

    /*
     * ========================================================================
     * RequestMapping
     * ========================================================================
     */

    @RequestMapping(value = "/", method = RequestMethod.GET)
    public String init(Model model) {
        // model.addAttribute(ATTRIBUTE_NAME_MSG,ATTRIBUTE_VAL_ENTER_USR_PWD);
        System.out.println("model test");
        return "login";
    }

    /*
     * String gRecaptchaResponse = loginBean.getgRecaptchaResponse()
     * System.out.println("captcha response "+gRecaptchaResponse); boolean verify =
     * VerifyRecaptcha.verify(gRecaptchaResponse);
     */

    @RequestMapping(value = "/login", method = RequestMethod.POST)
    public String submit(Model model, @ModelAttribute("loginBean") LoginBean loginBean, HttpServletRequest req)
            throws IOException {

        String gRecaptchaResponse = req.getParameter("g-recaptcha-response");
        System.out.println(gRecaptchaResponse);
        boolean verify = VerifyRecaptcha.verify(gRecaptchaResponse);
        System.out.println(verify);
        if (loginBean != null && loginBean.getUserName() != null && loginBean.getPassword() != null
                && verify != false) {
            SqlSession sqlSession = Connection.sqlSession(RESOURCE_PATH);
            AccountMapper accountMapper = sqlSession.getMapper(AccountMapper.class);

            // Set parameters to Account
            Account inputAccount = new Account();
            inputAccount.setUserName(loginBean.getUserName());
            inputAccount.setPassword(loginBean.getPassword());

            Account rs_account = accountMapper.getAccount(inputAccount);

            if (rs_account != null) {
                // if(inputAccount.setUserName(loginBean.getUserName()!=null)){
                model.addAttribute(ATTRIBUTE_NAME_MSG, "Welcome " + loginBean.getUserName());
                sqlSession.close();
                return "A4Print";
            } else {
                model.addAttribute(ATTRIBUTE_NAME_ERROR, ATTRIBUTE_VAL_INVALID);
                sqlSession.close();
                return "login";
            }
        } else {
            model.addAttribute(ATTRIBUTE_VAL_ENTER_USR_PWD, ATTRIBUTE_VAL_ENTER_RECAPTCHA);
            return "login";
        }
    }

    /*
     * ========================================================================
     * private method
     * ========================================================================
     */
}

错误消息

Sending 'POST' request to URL : https://www.google.com/recaptcha/api/siteverify Post parameters : secret6LcIicUUAAAAAOeuLpcAVmE53PYtPphreUT9FuVg&response=03AO LTBLSWWCbUzVHAfCZRYgrsnTt6VpW1nRx0NzI0FXUL1lngDgrSBbZbth0G5drjVCn6dtFBaygHibx7mRhkkI2cMJa0u0X9ls-

Response Code :200 TEst { "success": false, "error-codes": [ "missing-input-secret" ]} false