最近做了一个在线支付,哎呀,把我给折腾的可不轻.搞了很长时间.    PayPal 是一家 eBay 公司，它是在线付款解决方案的全球领导者，在全世界有超过七千一百六十万个帐户用户。PayPal 可由易趣买家和卖家、在线零售商和其他商家在 56 个市场以 6 种货币使用：加元 欧元 英镑 美元 日元 澳元；PayPal 快速、安全而又方便，是跨国交易的理想解决方案。国内的支付宝和PayPal 类型是差不多的！

随着制作外贸网站的数量增多，有些客户针对国外需要用到PayPal 支付接口，今天找了些PayPal 支付接口方面的资料，以备以后查询！也可以点GO去看原文档.

1.到https://developer.paypal.com/注册一个开发帐号，好了之后再进入Sandbox建立测试用的Paypal虚拟帐号（至少应该建立一个Business的和一个Personal的），信息可以是假的,注意:这里的至少两个测试帐号是在你所建立的开发帐号里面建立的,不要注册错了；

2.测试是很麻烦,但是是必不可少的,因为如果客户买过一次出错之后,就不会来第二次了,所以花半天时间做测试是很重要的；

3.代码帖出来给大家参考一下,我做的是不很细,支付成功后返回的结果我就没有做,因为我在测试的时候已经没有问题了,所以没有做,改天有空会完善的；

ASP.Net/C#

using System;
using System.IO;
using System.Text;
using System.Net;
using System.Web;

public partial class csIPNexample :System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//Post back to either sandbox or live
string strSandbox = "https://www.sandbox.paypal.com/cgi-bin/webscr";
string strLive = "https://www.paypal.com/cgi-bin/webscr";
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(strSandbox);

// Set values for the request back
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
byte[] param = Request.BinaryRead(HttpContext.Current.Request.ContentLength);
string strRequest = Encoding.ASCII.GetString(param);
strRequest += "&cmd=_notify-validate";
req.ContentLength = strRequest.Length;

//for proxy
//WebProxy proxy = new WebProxy(new Uri("http://url:port/#"));
//req.Proxy = proxy;

//Send the request to PayPal and get the response
StreamWriter streamOut = new StreamWriter(req.GetRequestStream(), System.Text.Encoding.ASCII);
streamOut.Write(strRequest);
streamOut.Close();
StreamReader streamIn = new StreamReader(req.GetResponse().GetResponseStream());
string strResponse = streamIn.ReadToEnd();
streamIn.Close();

if (strResponse == "VERIFIED")
{
// check the payment_status is Completed
// check that txn_id has not been previously processed
// check that receiver_email is your Primary PayPal email
// check that payment_amount/payment_currency are correct
// process payment
}
else if (strResponse == "INVALID")
{
// log for manual investigation
}
else
{
//log response/ipn data for manual investigation
}
}
}

ASP.Net/VB

Imports System.Net
Imports System.IO

Partial Class vbIPNexample
Inherits System.Web.UI.Page

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'Post back to either sandbox or live
Dim strSandbox As String = "https://www.sandbox.paypal.com/cgi-bin/webscr"
Dim strLive As String = "https://www.paypal.com/cgi-bin/webscr"
Dim req As HttpWebRequest = CType(WebRequest.Create(strSandbox), HttpWebRequest)

'Set values for the request back
req.Method = "POST"
req.ContentType = "application/x-www-form-urlencoded"
Dim Param() As Byte = Request.BinaryRead(HttpContext.Current.Request.ContentLength)
Dim strRequest As String = Encoding.ASCII.GetString(Param)
strRequest = strRequest + "&cmd=_notify-validate"
req.ContentLength = strRequest.Length

'for proxy
'Dim proxy As New WebProxy(New System.Uri("http://url:port/#"))
'req.Proxy = proxy

'Send the request to PayPal and get the response
Dim streamOut As StreamWriter = New StreamWriter(req.GetRequestStream(), Encoding.ASCII)
streamOut.Write(strRequest)
streamOut.Close()
Dim streamIn As StreamReader = New StreamReader(req.GetResponse().GetResponseStream())
Dim strResponse As String = streamIn.ReadToEnd()
streamIn.Close()

If strResponse = "VERIFIED" Then
'check the payment_status is Completed
'check that txn_id has not been previously processed
'check that receiver_email is your Primary PayPal email
'check that payment_amount/payment_currency are correct
'处理付款
ElseIf strResponse = "INVALID" Then
'log for manual investigation
Else
'Response wasn't VERIFIED or INVALID, log for manual investigation
End If
End Sub
End Class

ASP/VBScript
 
 
(requires MSXML)

<mailto:%@LANGUAGE="VBScript">
<%
Dim Item_name, Item_number, Payment_status, Payment_amount
Dim Txn_id, Receiver_email, Payer_email
Dim objHttp, str

' read post from PayPal system and add 'cmd'
str = Request.Form & "&cmd=_notify-validate"

' post back to PayPal system to validate
set objHttp = Server.CreateObject("Msxml2.ServerXMLHTTP")
' set objHttp = Server.CreateObject("Msxml2.ServerXMLHTTP.4.0")
' set objHttp = Server.CreateObject("Microsoft.XMLHTTP")
objHttp.open "POST", "https://www.paypal.com/cgi-bin/webscr", false
objHttp.setRequestHeader "Content-type", "application/x-www-form-urlencoded"
objHttp.Send str

' assign posted variables to local variables
Item_name = Request.Form("item_name")
Item_number = Request.Form("item_number")
Payment_status = Request.Form("payment_status")
Payment_amount = Request.Form("mc_gross")
Payment_currency = Request.Form("mc_currency")
Txn_id = Request.Form("txn_id")
Receiver_email = Request.Form("receiver_email")
Payer_email = Request.Form("payer_email")

' Check notification validation
if (objHttp.status <> 200 ) then
' HTTP error handling
elseif (objHttp.responseText = "VERIFIED") then
' check that Payment_status=Completed
' check that Txn_id has not been previously processed
' check that Receiver_email is your Primary PayPal email
' check that Payment_amount/Payment_currency are correct
' process payment
elseif (objHttp.responseText = "INVALID") then
' log for manual investigation
else
' error
end if
set objHttp = nothing
%>