Paypal空指针异常nvp.get(“确认”) Java

Question

我一整天都在为这个看似简单的集成而苦苦挣扎。我真的希望你能帮助我。

我需要在我的Java webapp中使用PayPal express结帐。我只需要下一个订单，并将客户端重定向到PayPal页面。

主页工作得很好，但当我尝试去结账时，我得到了一个NullPointerException。在我的Checkout类的第36行抛出了NullPointerException。当我尝试获取ACK时，它会被调用。

我已经试了一整天来解决这个问题。

不确定这是否相关:我已经创建了第二个项目，tapestry5项目，并使用Rest SDK，但当我尝试调用setExpressCheckoutResponse.getAck()时，仍然得到一个异常。我发现该项目中抛出异常的代码行是service.setExpressCheckout(setExpressCheckoutReq)；

如果你有任何想法，我可以解决这个问题，任何教程贝宝hello world与servlets或任何资源，我可以查看请帮助我。

下面是我一直在尝试的代码：

我的web.xml

<?xml version="1.0" encoding="ISO-8859-1" ?>

<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
    version="2.4">

    <display-name>Integration Wizard</display-name>
    <description></description>

    <servlet>
        <servlet-name>Checkout</servlet-name>
        <servlet-class>Checkout</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>Checkout</servlet-name>
        <url-pattern>/checkout</url-pattern>
    </servlet-mapping>

 <servlet>
        <servlet-name>OrderConfirm</servlet-name>
        <servlet-class>OrderConfirm</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>OrderConfirm</servlet-name>
        <url-pattern>/orderconfirm</url-pattern>
    </servlet-mapping>

     <servlet>
        <servlet-name>Cancel</servlet-name>
        <servlet-class>Cancel</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>Cancel</servlet-name>
        <url-pattern>/cancel</url-pattern>
    </servlet-mapping>



    <servlet>
        <servlet-name>HelloWorld</servlet-name>
        <servlet-class>HelloWorld</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>HelloWorld</servlet-name>
        <url-pattern>/HelloWorld</url-pattern>
    </servlet-mapping>
</web-app>  

我的HelloWorld.java (主页)

public class HelloWorld extends HttpServlet {

  private String message;

  public void init() throws ServletException {
      message = "Hello World";
  }

  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      response.setContentType("text/html");

      PrintWriter out = response.getWriter();
      out.println("");

      out.println("<!-- INFO: The post URL \"checkout.java\" is invoked when clicked on \"Pay with PayPal\" button.-->");

      out.println("<form action='/1/checkout' METHOD='POST'>");
      out.println("  <input type='image' name='paypal_submit' id='paypal_submit'  src='https://www.paypal.com/en_US/i/btn/btn_dg_pay_w_paypal.gif' border='0' align='top' alt='Pay with PayPal'/>");
      out.println("</form>");

      out.println("<!-- Add Digital goods in-context experience. Ensure that this script is added before the closing of html body tag -->");

      out.println("<script src='https://www.paypalobjects.com/js/external/dg.js' type='text/javascript'></script>");

      out.println("<script>");

      out.println("var dg = new PAYPAL.apps.DGFlow(");
      out.println("{");
      out.println("trigger: 'paypal_submit',");
      out.println("expType: 'instant'");
       out.println("//PayPal will decide the experience type for the buyer based on his/her 'Remember me on your computer' option.");
      out.println("});");

      out.println("</script>");
  }

  public void destroy() {
  }
}

我的Checkout.java (这里的NullPointerException在第36行抛出)

public class Checkout extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {


        String paymentAmount = "15.00";

        String returnURL = "localhost:8080/1/HelloWorld";

        String cancelURL = "localhost:8080/1/HelloWorld";

        Map item = new HashMap();
        item.put("name", "item name");
        item.put("amt", paymentAmount);
        item.put("qty", "1");

        PaypalFunctions ppf = new PaypalFunctions();
        HashMap nvp = ppf.setExpressCheckout(paymentAmount, returnURL,
                cancelURL, item);
        String strAck = nvp.get("ACK").toString();

        if (strAck != null && strAck.equalsIgnoreCase("Success")) {

            // ' Redirect to paypal.com
            String redirectURL = "https://www.sandbox.paypal.com/incontext?token="
                    + nvp.get("TOKEN").toString();

            response.sendRedirect(redirectURL);
        } else {
            // Display a user friendly Error on the page using any of the
            // following error information returned by PayPal

            String ErrorCode = nvp.get("L_ERRORCODE0").toString();
            String ErrorShortMsg = nvp.get("L_SHORTMESSAGE0").toString();
            String ErrorLongMsg = nvp.get("L_LONGMESSAGE0").toString();
            String ErrorSeverityCode = nvp.get("L_SEVERITYCODE0").toString();
        }
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

}

我的PaypalFunctions.java

public class PaypalFunctions {
    private String gv_APIUserName;
    private String gv_APIPassword;
    private String gv_APISignature;

    private String gv_APIEndpoint;
    private String gv_BNCode;

    private String gv_Version;
    private String gv_nvpHeader;
    private String gv_ProxyServer;
    private String gv_ProxyServerPort;
    private int gv_Proxy;
    private boolean gv_UseProxy;
    private String PAYPAL_URL;

    public PaypalFunctions() {

        gv_APIUserName = "dusan.stanojevic95-facilitator_api1.gmail.com";
        gv_APIPassword = "1405890612";
        gv_APISignature = "AexbutlMdUCD618gs-q4m-DJpUxEAoU-uNDtNNLAb47Su-QoOlNbIjeo";

        boolean bSandbox = true;

        String PAYPAL_DG_URL = null;
        if (bSandbox == true) {
            gv_APIEndpoint = "https://api-3t.sandbox.paypal.com/nvp";
            PAYPAL_URL = "https://www.sandbox.paypal.com/webscr?cmd=_express-checkout&token=";
            PAYPAL_DG_URL = "https://www.sandbox.paypal.com/incontext?token=";
        } else {
            gv_APIEndpoint = "https://api-3t.paypal.com/nvp";
            PAYPAL_URL = "https://www.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token=";
            PAYPAL_DG_URL = "https://www.paypal.com/incontext?token=";
        }

        String HTTPREQUEST_PROXYSETTING_SERVER = "";
        String HTTPREQUEST_PROXYSETTING_PORT = "";
        boolean USE_PROXY = false;

        gv_Version = "84";

        // WinObjHttp Request proxy settings.
        gv_ProxyServer = HTTPREQUEST_PROXYSETTING_SERVER;
        gv_ProxyServerPort = HTTPREQUEST_PROXYSETTING_PORT;
        gv_Proxy = 2; // 'setting for proxy activation
        gv_UseProxy = USE_PROXY;

    }

    /*********************************************************************************
     * SetExpressCheckout: Function to perform the SetExpressCheckout API call
     * 
     * Inputs: paymentAmount: Total value of the purchase currencyCodeType:
     * Currency code value the PayPal API paymentType: 'Sale' for Digital Goods
     * returnURL: the page where buyers return to after they are done with the
     * payment review on PayPal cancelURL: the page where buyers return to when
     * they cancel the payment review on PayPal
     * 
     * Output: Returns a HashMap object containing the response from the server.
     *********************************************************************************/
    public HashMap setExpressCheckout(String paymentAmount, String returnURL,
            String cancelURL, Map item) {

        /*
         * '------------------------------------ ' The currencyCodeType and
         * paymentType ' are set to the selections made on the Integration
         * Assistant '------------------------------------
         */

        String currencyCodeType = "USD";
        String paymentType = "Sale";

        /*
         * Construct the parameter string that describes the PayPal payment the
         * varialbes were set in the web form, and the resulting string is
         * stored in $nvpstr
         */
        String nvpstr = "&PAYMENTREQUEST_0_AMT=" + paymentAmount
                + "&PAYMENTREQUEST_0_PAYMENTACTION=" + paymentType
                + "&RETURNURL=" + URLEncoder.encode(returnURL) + "&CANCELURL="
                + URLEncoder.encode(cancelURL)
                + "&PAYMENTREQUEST_0_CURRENCYCODE=" + currencyCodeType
                + "&REQCONFIRMSHIPPING=0" + "&NOSHIPPING=1"
                + "&L_PAYMENTREQUEST_0_NAME0=" + item.get("name")
                + "&L_PAYMENTREQUEST_0_AMT0=" + item.get("amt")
                + "&L_PAYMENTREQUEST_0_QTY0=" + item.get("qty")
                + "&L_PAYMENTREQUEST_0_ITEMCATEGORY0=Digital";

        /*
         * Make the call to PayPal to get the Express Checkout token If the API
         * call succeded, then redirect the buyer to PayPal to begin to
         * authorize payment. If an error occured, show the resulting errors
         */

        HashMap nvp = httpcall("SetExpressCheckout", nvpstr);

        String strAck = nvp.get("ACK").toString();
        if (strAck != null && strAck.equalsIgnoreCase("Success")) {

            return nvp;
        }

        return null;
    }

    /*********************************************************************************
     * GetShippingDetails: Function to perform the GetExpressCheckoutDetails API
     * call
     * 
     * Inputs: None
     * 
     * Output: Returns a HashMap object containing the response from the server.
     *********************************************************************************/
    public HashMap getPaymentDetails(String token) {
        /*
         * Build a second API request to PayPal, using the token as the ID to
         * get the details on the payment authorization
         */

        String nvpstr = "&TOKEN=" + token;

        /*
         * Make the API call and store the results in an array. If the call was
         * a success, show the authorization details, and provide an action to
         * complete the payment. If failed, show the error
         */

        HashMap nvp = httpcall("GetExpressCheckoutDetails", nvpstr);
        String strAck = nvp.get("ACK").toString();

        if (strAck != null
                && (strAck.equalsIgnoreCase("Success") || strAck
                        .equalsIgnoreCase("SuccessWithWarning"))) {

            return nvp;
        }
        return null;
    }

    /*********************************************************************************
     * ConfirmPayment: Function to perform the DoExpressCheckoutPayment API call
     * 
     * Inputs: None
     * 
     * Output: Returns a HashMap object containing the response from the server.
     *********************************************************************************/
    public HashMap confirmPayment(String token, String payerID,
            String finalPaymentAmount, String serverName, Map item) {

        /*
         * '------------------------------------ ' The currencyCodeType and
         * paymentType ' are set to the selections made on the Integration
         * Assistant '------------------------------------
         */
        String currencyCodeType = "USD";
        String paymentType = "Sale";

        /*
         * '----------------------------------------------------------------------------
         * '---- Use the values stored in the session from the previous SetEC
         * call
         * '----------------------------------------------------------------------------
         */
        String nvpstr = "&TOKEN=" + token + "&PAYERID=" + payerID
                + "&PAYMENTREQUEST_0_PAYMENTACTION=" + paymentType + "&PAYMENTREQUEST_0_AMT="
                + finalPaymentAmount;

        nvpstr = nvpstr + "&PAYMENTREQUEST_0_CURRENCYCODE=" + currencyCodeType + "&IPADDRESS="
                + serverName;

        nvpstr = nvpstr + "&L_PAYMENTREQUEST_0_NAME0=" + item.get("name")
                + "&L_PAYMENTREQUEST_0_AMT0=" + item.get("amt")
                + "&L_PAYMENTREQUEST_0_QTY0=" + item.get("qty")
                + "&L_PAYMENTREQUEST_0_ITEMCATEGORY0=Digital";

        /*
         * Make the call to PayPal to finalize payment If an error occured, show
         * the resulting errors
         */
        HashMap nvp = httpcall("DoExpressCheckoutPayment", nvpstr);
        String strAck = nvp.get("ACK").toString();
        if (strAck != null
                && (strAck.equalsIgnoreCase("Success") || strAck
                        .equalsIgnoreCase("SuccessWithWarning"))) {
            return nvp;
        }
        return null;

    }

    /*********************************************************************************
     * httpcall: Function to perform the API call to PayPal using API signature @
     * methodName is name of API method. @ nvpStr is nvp string. returns a NVP
     * string containing the response from the server.
     *********************************************************************************/
    public HashMap httpcall(String methodName, String nvpStr) {

        String version = "2.3";
        String agent = "Mozilla/4.0";
        String respText = "";
        HashMap nvp = null; // lhuynh not used?

        // deformatNVP( nvpStr );
        String encodedData = "METHOD=" + methodName + "&VERSION=" + gv_Version
                + "&PWD=" + gv_APIPassword + "&USER=" + gv_APIUserName
                + "&SIGNATURE=" + gv_APISignature + nvpStr;

        try {
            URL postURL = new URL(gv_APIEndpoint);
            HttpURLConnection conn = (HttpURLConnection) postURL
                    .openConnection();

            // Set connection parameters. We need to perform input and output,
            // so set both as true.
            conn.setDoInput(true);
            conn.setDoOutput(true);

            // Set the content type we are POSTing. We impersonate it as
            // encoded form data
            conn.setRequestProperty("Content-Type",
                    "application/x-www-form-urlencoded");
            conn.setRequestProperty("User-Agent", agent);

            // conn.setRequestProperty( "Content-Type", type );
            conn.setRequestProperty("Content-Length",
                    String.valueOf(encodedData.length()));
            conn.setRequestMethod("POST");

            // get the output stream to POST to.
            DataOutputStream output = new DataOutputStream(
                    conn.getOutputStream());
            output.writeBytes(encodedData);
            output.flush();
            output.close();

            // Read input from the input stream.
            DataInputStream in = new DataInputStream(conn.getInputStream());
            int rc = conn.getResponseCode();
            if (rc != -1) {
                BufferedReader is = new BufferedReader(new InputStreamReader(
                        conn.getInputStream()));
                String _line = null;
                while (((_line = is.readLine()) != null)) {
                    respText = respText + _line;
                }
                nvp = deformatNVP(respText);
            }
            return nvp;
        } catch (IOException e) {
            // handle the error here
            return null;
        }
    }

    /*********************************************************************************
     * deformatNVP: Function to break the NVP string into a HashMap pPayLoad is
     * the NVP string. returns a HashMap object containing all the name value
     * pairs of the string.
     *********************************************************************************/
    public HashMap deformatNVP(String pPayload) {
        HashMap nvp = new HashMap();
        StringTokenizer stTok = new StringTokenizer(pPayload, "&");
        while (stTok.hasMoreTokens()) {
            StringTokenizer stInternalTokenizer = new StringTokenizer(
                    stTok.nextToken(), "=");
            if (stInternalTokenizer.countTokens() == 2) {
                String key = URLDecoder.decode(stInternalTokenizer.nextToken());
                String value = URLDecoder.decode(stInternalTokenizer
                        .nextToken());
                nvp.put(key.toUpperCase(), value);
            }
        }
        return nvp;
    }

    /*********************************************************************************
     * RedirectURL: Function to redirect the user to the PayPal site token is
     * the parameter that was returned by PayPal returns a HashMap object
     * containing all the name value pairs of the string.
     *********************************************************************************/
    public void RedirectURL(HttpServletResponse response, String token) {
        String payPalURL = PAYPAL_URL + token;

        // response.sendRedirect( payPalURL );
        response.setStatus(302);
        response.setHeader("Location", payPalURL);
        response.setHeader("Connection", "close");
    }

    // end class
}

Answer 1

我不能解决我的问题，但是我能够完成我的项目。我放弃了所有这些代码，并尝试了以下示例项目：

https://github.com/paypal/merchant-sdk-java。

这个项目起作用了，所以我只是改变了值，删除了所有不必要的代码，并重写了代码，以便在我的Tapestry5应用程序中运行。

总有一天我会回去找出为什么以前使用的代码不能工作，我想是糟糕的maven依赖，但我们会看到的。

感谢大家的帮助。

Answer 2

请更改以下变量：

String returnURL = "localhost:8080/1/HelloWorld";
String cancelURL = "localhost:8080/1/HelloWorld";

至

String returnURL = "http://localhost:8080/1/HelloWorld";
String cancelURL = "http://localhost:8080/1/HelloWorld";

问题:无法验证Url，因为它没有"http://“”