关于jakarta ee：PayPal REST API未执行付款。无法将付款对象的状态从”已创建”更改为”已批准”或”已完成”

PayPal REST API is not executing payments. Cannot change state of Payment object from 'created' to 'approved' or 'completed'

我正在使用servlet生成HTML页面，这些页面旨在使用新的REST API执行PayPal付款。我尚未能够生成状态为已批准或已创建的付款。我已经在github页面上的PaymentWithPayPalServlet.java示例中尝试了变体，并且在下面添加了最接近的变体。我最不清楚哪个对象应该接收到"已批准"或"已完成"的更新状态以及何时接收。

尽管我已经在下面包含了完整的代码，但是这是我的想法的快速分解。也许有人可以纠正我哪里出错了...

我创建了具有所有适当属性/属性集的Payment对象。

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Payment payment = new Payment();
payment.setIntent("sale");
payment.setPayer(payer);
payment.setTransactions(transactions);
payment.setRedirectUrls(redirectUrls);
Payment createdPayment = payment.create(apiContext);

现在，createdPayment对象的状态为" created "。在我的代码末尾，我将用户重定向到payPal页面，在该页面上我假定payPal将在执行之前批准付款。请注意，这与示例文件有所不同，但我不明白为什么这不起作用。

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if (link.getRel().equalsIgnoreCase("approval_url"))
{
req.setAttribute("redirectURL", link.getHref());
resp.sendRedirect(link.getHref());
}

由于payPal无法通过HTTP协议更改我的本地变量createdPayment的状态，因此我希望payPal页面重定向回我的returnURL页面，该页面的payingID以及可能附加在URL上的授权令牌。使用这两件事，我希望可以通过某种类型的静态函数调用从payPal服务器检索付款对象，例如：

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String authToken=req.getParameter("token");
String paymentID=req.getParameter("paymentID");
Payment approvedPayment=Payment.getPaymentObject(authToken,paymentID);

但是，URL没有附加任何PaymentID。而是有一个payerID。此外，我所有从PayPal服务器检索状态为"已批准"或"已完成"的付款对象的尝试均失败了。基本上，我尝试了以下变化，但无济于事：

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String authToken=req.getParameter("token");
String paymentID=req.getParameter("payerID");
Payment approvedPayment=Payment.get(authToken,payerID);

如果有人可以提示我我的推理出了问题，那肯定会很艰难。谢谢！这是我的主要servlet页面中的完整代码。请注意，returnURL将您带回到同一页面，在该页面中找到来自payPal的HTTP请求中包含的payerID，并正确输入主if-else语句的\\'if \\'块，这将生成一些基本输出，该输出完全无益的。还要注意，我已经将一些基本的函数调用(如检索访问令牌和上下文)外包给了其他类，如AccessToken类。

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public class PaymentInfoServlet2 extends HttpServlet {

private static final long serialVersionUID = 1L;

// private static final Logger LOGGER = Logger
// .getLogger(PaymentWithPayPalServlet.class);
Map<String, String> map = new HashMap<String, String>();

public void init(ServletConfig servletConfig) throws ServletException {
// ##Load Configuration
// Load SDK configuration for
// the resource. This intialization code can be
// done as Init Servlet.
InputStream is = PaymentInfoServlet2.class
.getResourceAsStream("/sdk_config.properties");
try {
PayPalResource.initConfig(is);
} catch (PayPalRESTException e) {
// LOGGER.fatal(e.getMessage());
}

}

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
doPost(req, resp);
}

// ##Create
// Sample showing to create a Payment using PayPal
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// ###AccessToken
// Retrieve the access token from
// OAuthTokenCredential by passing in
// ClientID and ClientSecret
APIContext apiContext = null;
String accessToken = null;
try {
AccessToken access=new AccessToken(PublicUtils.getUser(),PublicUtils.getPass(),req,resp);

accessToken = access.getToken();

// ### Api Context
// Pass in a `ApiContext` object to authenticate
// the call and to send a unique request id
// (that ensures idempotency). The SDK generates
// a request id if you do not pass one explicitly.
apiContext = access.getContext();
// Use this variant if you want to pass in a request id
// that is meaningful in your application, ideally
// a order id.
/*
* String requestId = Long.toString(System.nanoTime(); APIContext
* apiContext = new APIContext(accessToken, requestId ));
*/
} catch (Exception e) {
req.setAttribute("error", e.getMessage());
}
if (req.getParameter("PayerID") != null) {
Payment payment = new Payment();
if (req.getParameter("guid") != null) {
payment.setId(map.get(req.getParameter("guid")));
}

PaymentExecution paymentExecution = new PaymentExecution();
paymentExecution.setPayerId(req.getParameter("PayerID"));
try {
payment.execute(apiContext, paymentExecution);
req.setAttribute("response", Payment.getLastResponse());
} catch (PayPalRESTException e) {
req.setAttribute("error", e.getMessage());
}
PrintWriter out=resp.getWriter();
out.println("This is the returnURL page.");
out.println("paymentID="+payment.getId());
out.println("pamentState="+payment.getState());
out.println("executedPayerID="+paymentExecution.getPayerId());
// out.println("executedTransaction:"+paymentExecution.getTransactions().get(0).toString());
} else {

// ###Details
// Let's you specify details of a payment amount.
Details details = new Details();
details.setShipping("1");
details.setSubtotal("5");
details.setTax("1");

// ###Amount
// Let's you specify a payment amount.
Amount amount = new Amount();
amount.setCurrency("USD");
// Total must be equal to sum of shipping, tax and subtotal.
amount.setTotal("7");
amount.setDetails(details);

// ###Transaction
// A transaction defines the contract of a
// payment - what is the payment for and who
// is fulfilling it. Transaction is created with
// a `Payee` and `Amount` types
Transaction transaction = new Transaction();
transaction.setAmount(amount);
transaction
.setDescription("This is the payment transaction description.");

// The Payment creation API requires a list of
// Transaction; add the created `Transaction`
// to a List
List<Transaction> transactions = new ArrayList<Transaction>();
transactions.add(transaction);

// ###Payer
// A resource representing a Payer that funds a payment
// Payment Method
// as 'paypal'
Payer payer = new Payer();
payer.setPaymentMethod("paypal");

// ###Payment
// A Payment Resource; create one using
// the above types and intent as 'sale'
Payment payment = new Payment();
payment.setIntent("sale");
payment.setPayer(payer);
payment.setTransactions(transactions);

// ###Redirect URLs
RedirectUrls redirectUrls = new RedirectUrls();
String guid = UUID.randomUUID().toString().replaceAll("-","");
redirectUrls.setCancelUrl(req.getScheme() +"://"
+ req.getServerName() +":" + req.getServerPort()
+ req.getContextPath() +"/CancelServlet?guid=" + guid);
redirectUrls.setReturnUrl(req.getScheme() +"://"
+ req.getServerName() +":" + req.getServerPort()
+ req.getContextPath() +"/PaymentInfoServlet2?guid=" + guid);
payment.setRedirectUrls(redirectUrls);

// Create a payment by posting to the APIService
// using a valid AccessToken
// The return object contains the status;
try {
Payment createdPayment = payment.create(apiContext);
// LOGGER.info("Created payment with id ="
// + createdPayment.getId() +" and status ="
// + createdPayment.getState());
// ###Payment Approval Url
Iterator<Links> links = createdPayment.getLinks().iterator();
while (links.hasNext()) {
Links link = links.next();
if (link.getRel().equalsIgnoreCase("approval_url")) {
req.setAttribute("redirectURL", link.getHref());
resp.sendRedirect(link.getHref());
}
}
req.setAttribute("response", Payment.getLastResponse());
map.put(guid, createdPayment.getId());
} catch (PayPalRESTException e) {
req.setAttribute("error", e.getMessage());
}
}
req.setAttribute("request", Payment.getLastRequest());
//req.getRequestDispatcher("response.jsp").forward(req, resp);
}

} ??

为回应我在下面的第一个评论者Yozha Karlov，我添加了以下内容：

好吧，我想我对此有几个反应。首先，谢谢。第二，我想也许我对我的问题还不够清楚。对于如何检索上面名为\\'createdPayment \\'的旧付款对象，我并不感到困惑。在上面复制的完整代码中，我使用与您引用的完全相同的guid代码。这样做的一个问题是，除了将createdPayment对象的ID复制到新的空白Payment对象之外，它什么也不做。新对象的状态以及其他所有属性仍然为空白。它是一个具有ID的空白对象，仅此而已。几乎一文不值，所以我要么丢失了某些东西，要么示例servlet是完全错误的。

实际上，我的初始方法是创建一个带有静态映射的静态类，以将sessionID映射到HttpSession对象。我将为用户的浏览器会话生成一个sessionID，并将该sessID附加到payment.create()方法的redirectURLs中的cancelURL和returnURL中。然后，请确保将相关的Payment对象附加到用户的HttpSession对象中，以便以后在returnURL servlet中进行检索。

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public class SessionStore {
public static Map<String, HttpSession> map = new HashMap<String,HttpSession>();
}

and in my main servlet, called PaymentInfoServlet2, here is the relevant code that i execute before the servlet ends and the user is re-directed to the payPal pages:

HttpSession sess=req.getSession();
String sessID=sess.getId();
SessionStore.map.put(sessID, sess);

// append sessID to redirectURLs - the URLs that the payPal pages return back to
approveURL=req.getScheme() +"://"+ req.getServerName() +":" +req.getServerPort()+ req.getContextPath() +"/ApproveServlet?sessID=" +sess.getId();
cancelURL=req.getScheme() +"://"+ req.getServerName() +":" + req.getServerPort()+ req.getContextPath() +"/CancelServlet?sessID=" +sess.getId();
redirectUrls.setCancelUrl(cancelURL);
redirectUrls.setReturnUrl(approveURL);
payment.setRedirectUrls(redirectUrls);

// create the payment on the payPal server
Payment createdPayment = payment.create(access.getContext());

//add created Payment object to HttpSession object.
ArrayList<Payment> createdPayments=new ArrayList<Payment>();
createdPayments.add(createdPayment);
sess.setAttribute("createdPayments", createdPayments);

// redirect to payPal pages
Iterator<Links> links = createdPayment.getLinks().iterator();
while (links.hasNext())
{
Links link = links.next();
if (link.getRel().equalsIgnoreCase("approval_url"))
{
url=link.getHref();
resp.sendRedirect(url);
}
}

然后，当payPal页面将我返回到我以前的returnURL页面时，我将调用以下相关代码片段：

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String sessID=req.getParameter("sessID");
HttpSession sess=SessionStore.map.get(sessID);
ArrayList<Payment> cPay=(ArrayList<Payment>)sess.getAttribute("createdPayments");
Payment payment=(Payment)cPay.get(0);

和具有所有相同属性和所有内容的旧付款对象已被检索。这似乎比仅将旧付款ID复制到否则为空白的Payment对象中更为有用。但是，旧的"创建的付款"是什么？仍然处于"创建"状态，而不是"已批准"状态或" completeda"。我不知道如何从上面已经概述的对象创建到执行相同的Payment对象的过程。实际上，我什至不了解使用方法付款是否等于paypala？应该使用相同的付款对象创建和执行。正如我在原始帖子中所描述的那样，对我来说应该是没有道理的。我创建了一个付款对象，payPal发回了一个roval_URL，其中包括我，用于将用户重定向到以进行批准。这会将用户带离我的Web应用程序，并进入Pay??Pal服务器。由于PayPal无法修改我的本地" createdPaymenta"？变量，贝宝(PayPal)无法更改其状态。此外，似乎我需要状态为"已批准"的"付款"对象。为了执行付款。因此，我得出结论，贝宝(PayPal)必须向我发送一个新的Payment对象，该对象应具有与我的createdPaymenta相同的信息。对象，但具有已批准状态的更新状态，并且可能具有指示已批准状态的特殊令牌/密码，以防止某人将一大笔付款入侵已批准状态，这很容易做到。我看到我正在按预期方式获得令牌，但是我没有按预期获得付款ID。我正在获取一个payerID。有没有一种方法可以将返回的令牌和payerID转换为状态为a？approveda？的新Payment对象，或者我只是完全丢失了什么？

是的，从PayPal网站页面重定向后，" payerId"将被附加为请求参数，而不是付款ID。但是您还需要付款ID才能执行它。这是来自payPal交互工具的代码。

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String accessToken ="Bearer Jfdd4h4VrmvLeATBNPsGOpp7pMosTppiy.Jq6xpwQ6E";
APIContext apiContext = new APIContext(accessToken);
apiContext.setConfigurationMap(sdkConfig);

Payment payment = new Payment("PAY-4AL22602580048540KKPBSNY");
PaymentExecution paymentExecute = new PaymentExecution();
paymentExecute.setPayerId("BKJ78SZZ8KJYY");
payment.execute(apiContext, paymentExecute);

因此，棘手的部分是如何保留请求之间的付款ID，因为众所周知，HTTP不保存任何状态。您可以在引用的示例中看到它的实现方式：

https://github.com/paypal/rest-api-sdk-java/blob/master/rest-api-sample/src/main/java/com/paypal/api/payments/servlet/PaymentWithPayPalServlet.java

因此它们生成uuid：

1	String guid = UUID.randomUUID().toString().replaceAll("-","");

在重定向URL中添加guid参数：

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redirectUrls.setReturnUrl(req.getScheme() +"://"
+ req.getServerName() +":" + req.getServerPort()
+ req.getContextPath() +"/paymentwithpaypal?guid=" + guid);

，并将此guid参数与创建的付款ID相关联：

1	map.put(guid, createdPayment.getId());

以便以后使用它

1	payment.setId(map.get(req.getParameter("guid")));

希望这会有所帮助