首先，您将一些旧变量与新变量混合在一起，并且您正在使用一些新旧变量相同的变量。这是您的请求应该传递的内容。一旦您以这种格式传递这些变量，您的请求就会通过。
RETURNURL=http://www.mydomainname.com/pp/paypal/process.php
CANCELURL=http://www.mydomainname.com/pp/paypal/cancel_url.php
ALLOWNOTE=1
PAYMENTREQUEST_0_PAYMENTACTION=Sale
PAYMENTREQUEST_0_CURRENCYCODE=EUR
PAYMENTREQUEST_0_AMT=106.72
PAYMENTREQUEST_0_ITEMAMT=106.72
L_PAYMENTREQUEST_0_QTY0=3
L_PAYMENTREQUEST_0_AMT0=28.46
L_PAYMENTREQUEST_0_NAME0=FIRSTitem
L_PAYMENTREQUEST_0_NUMBER0=0
L_PAYMENTREQUEST_0_QTY1=1
L_PAYMENTREQUEST_0_AMT1=21.34
L_PAYMENTREQUEST_0_NAME1=SECONDitem
L_PAYMENTREQUEST_0_NUMBER1=1
以下是我在 Express Checkout API 调用中从头到尾传递的内容。
SetExpressCheckout API 请求：
USER=xxxxxxxxxx
PWD=xxxxxxxxxx
SIGNATURE=xxxxxxxxxx
METHOD=SetExpressCheckout
VERSION=98.0
RETURNURL=xxxxxxxxxx
CANCELURL=xxxxxxxxxx
ALLOWNOTE=1
PAYMENTREQUEST_0_PAYMENTACTION=Sale
PAYMENTREQUEST_0_CURRENCYCODE=EUR
PAYMENTREQUEST_0_AMT=106.72
PAYMENTREQUEST_0_ITEMAMT=106.72
L_PAYMENTREQUEST_0_QTY0=3
L_PAYMENTREQUEST_0_AMT0=28.46
L_PAYMENTREQUEST_0_NAME0=FIRSTitem
L_PAYMENTREQUEST_0_NUMBER0=0
L_PAYMENTREQUEST_0_QTY1=1
L_PAYMENTREQUEST_0_AMT1=21.34
L_PAYMENTREQUEST_0_NAME1=SECONDitem
L_PAYMENTREQUEST_0_NUMBER1=1
SetExpressCheckout API 响应：
TOKEN=EC-3TL21567PX031102F
TIMESTAMP=2013-05-01T17:55:07Z
CORRELATIONID=57357a4d9619c
ACK=Success
VERSION=98.0
BUILD=5817241
GetExpressCheckoutDetails API 请求：
USER=xxxxxxxxxx
PWD=xxxxxxxxxx
SIGNATURE=xxxxxxxxxx
METHOD=GetExpressCheckoutDetails
VERSION=98.0
TOKEN=EC-3TL21567PX031102F
GetExpressCheckoutDetails API 响应：
TOKEN=EC-3TL21567PX031102F
CHECKOUTSTATUS=PaymentActionNotInitiated
TIMESTAMP=2013-05-01T17:56:26Z
CORRELATIONID=69c3839d7aedd
ACK=Success
VERSION=98.0
BUILD=5817241
EMAIL=mts_us_per@ccaples.com
PAYERID=EW4KQ9CQX45F6
PAYERSTATUS=verified
FIRSTNAME=MTS
LASTNAME=Testing
COUNTRYCODE=US
SHIPTONAME=PayPal PayPal
SHIPTOSTREET=123 street
SHIPTOCITY=omaha
SHIPTOSTATE=NE
SHIPTOZIP=68138
SHIPTOCOUNTRYCODE=US
SHIPTOCOUNTRYNAME=United States
ADDRESSSTATUS=Confirmed
CURRENCYCODE=EUR
AMT=106.72
ITEMAMT=106.72
SHIPPINGAMT=0.00
HANDLINGAMT=0.00
TAXAMT=0.00
INSURANCEAMT=0.00
SHIPDISCAMT=0.00
L_NAME0=FIRSTitem
L_NAME1=SECONDitem
L_NUMBER0=0
L_NUMBER1=1
L_QTY0=3
L_QTY1=1
L_TAXAMT0=0.00
L_TAXAMT1=0.00
L_AMT0=28.46
L_AMT1=21.34
L_ITEMWEIGHTVALUE0= 0.00000
L_ITEMWEIGHTVALUE1= 0.00000
L_ITEMLENGTHVALUE0= 0.00000
L_ITEMLENGTHVALUE1= 0.00000
L_ITEMWIDTHVALUE0= 0.00000
L_ITEMWIDTHVALUE1= 0.00000
L_ITEMHEIGHTVALUE0= 0.00000
L_ITEMHEIGHTVALUE1= 0.00000
PAYMENTREQUEST_0_CURRENCYCODE=EUR
PAYMENTREQUEST_0_AMT=106.72
PAYMENTREQUEST_0_ITEMAMT=106.72
PAYMENTREQUEST_0_SHIPPINGAMT=0.00
PAYMENTREQUEST_0_HANDLINGAMT=0.00
PAYMENTREQUEST_0_TAXAMT=0.00
PAYMENTREQUEST_0_INSURANCEAMT=0.00
PAYMENTREQUEST_0_SHIPDISCAMT=0.00
PAYMENTREQUEST_0_INSURANCEOPTIONOFFERED=false
PAYMENTREQUEST_0_SHIPTONAME=PayPal PayPal
PAYMENTREQUEST_0_SHIPTOSTREET=123 street
PAYMENTREQUEST_0_SHIPTOCITY=omaha
PAYMENTREQUEST_0_SHIPTOSTATE=NE
PAYMENTREQUEST_0_SHIPTOZIP=68138
PAYMENTREQUEST_0_SHIPTOCOUNTRYCODE=US
PAYMENTREQUEST_0_SHIPTOCOUNTRYNAME=United States
PAYMENTREQUEST_0_ADDRESSSTATUS=Confirmed
PAYMENTREQUEST_0_ADDRESSNORMALIZATIONSTATUS=None
L_PAYMENTREQUEST_0_NAME0=FIRSTitem
L_PAYMENTREQUEST_0_NAME1=SECONDitem
L_PAYMENTREQUEST_0_NUMBER0=0
L_PAYMENTREQUEST_0_NUMBER1=1
L_PAYMENTREQUEST_0_QTY0=3
L_PAYMENTREQUEST_0_QTY1=1
L_PAYMENTREQUEST_0_TAXAMT0=0.00
L_PAYMENTREQUEST_0_TAXAMT1=0.00
L_PAYMENTREQUEST_0_AMT0=28.46
L_PAYMENTREQUEST_0_AMT1=21.34
L_PAYMENTREQUEST_0_ITEMWEIGHTVALUE0= 0.00000
L_PAYMENTREQUEST_0_ITEMWEIGHTVALUE1= 0.00000
L_PAYMENTREQUEST_0_ITEMLENGTHVALUE0= 0.00000
L_PAYMENTREQUEST_0_ITEMLENGTHVALUE1= 0.00000
L_PAYMENTREQUEST_0_ITEMWIDTHVALUE0= 0.00000
L_PAYMENTREQUEST_0_ITEMWIDTHVALUE1= 0.00000
L_PAYMENTREQUEST_0_ITEMHEIGHTVALUE0= 0.00000
L_PAYMENTREQUEST_0_ITEMHEIGHTVALUE1= 0.00000
PAYMENTREQUESTINFO_0_ERRORCODE=0
DoExpressCheckoutPayment API 请求：
USER=xxxxxxxxxx
PWD=xxxxxxxxxx
SIGNATURE=xxxxxxxxxx
METHOD=DoExpressCheckoutPayment
VERSION=98.0
TOKEN=EC-3TL21567PX031102F
PAYERID=EW4KQ9CQX45F6
PAYMENTREQUEST_0_PAYMENTACTION=Sale
PAYMENTREQUEST_0_CURRENCYCODE=EUR
PAYMENTREQUEST_0_AMT=106.72
PAYMENTREQUEST_0_ITEMAMT=106.72
L_PAYMENTREQUEST_0_QTY0=3
L_PAYMENTREQUEST_0_AMT0=28.46
L_PAYMENTREQUEST_0_NAME0=FIRSTitem
L_PAYMENTREQUEST_0_NUMBER0=0
L_PAYMENTREQUEST_0_QTY1=1
L_PAYMENTREQUEST_0_AMT1=21.34
L_PAYMENTREQUEST_0_NAME1=SECONDitem
L_PAYMENTREQUEST_0_NUMBER1=1
DoExpressCheckoutPayment API 响应：
TOKEN=EC-3TL21567PX031102F
SUCCESSPAGEREDIRECTREQUESTED=false
TIMESTAMP=2013-05-01T17:57:16Z
CORRELATIONID=fb8b667b499a0
ACK=Success
VERSION=98.0
BUILD=5817241
INSURANCEOPTIONSELECTED=false
SHIPPINGOPTIONISDEFAULT=false
PAYMENTINFO_0_TRANSACTIONID=5YP27805RR1557744
PAYMENTINFO_0_TRANSACTIONTYPE=cart
PAYMENTINFO_0_PAYMENTTYPE=instant
PAYMENTINFO_0_ORDERTIME=2013-05-01T17:57:15Z
PAYMENTINFO_0_AMT=106.72
PAYMENTINFO_0_FEEAMT=3.44
PAYMENTINFO_0_SETTLEAMT=137.23
PAYMENTINFO_0_TAXAMT=0.00
PAYMENTINFO_0_CURRENCYCODE=EUR
PAYMENTINFO_0_EXCHANGERATE=1.32871
PAYMENTINFO_0_PAYMENTSTATUS=Completed
PAYMENTINFO_0_PENDINGREASON=None
PAYMENTINFO_0_REASONCODE=None
PAYMENTINFO_0_PROTECTIONELIGIBILITY=Eligible
PAYMENTINFO_0_PROTECTIONELIGIBILITYTYPE=ItemNotReceivedEligible,UnauthorizedPaymentEligible
PAYMENTINFO_0_SECUREMERCHANTACCOUNTID=6CFEBJAE59DAY
PAYMENTINFO_0_ERRORCODE=0
PAYMENTINFO_0_ACK=Success