1、HTTP 只有POST和GET 兩種命令模式；
2、POST是被設計用來向上放東西的，而GET是被設計用來從服務器取東西的，GET也能夠向服務器傳送較少的數據，而Get之所以也能傳送數據,只是用來設計告訴服務器,你到底需要什么樣的數據.POST的信息作為HTTP 請求的內容，而GET是在HTTP 頭部傳輸的；
3、POST與GET在HTTP 中傳送的方式不同，GET的參數是在HTTP 的頭部傳送的，而Post的數據則是在HTTP 請求的內容里傳送;
4、POST傳輸數據時，不需要在URL中顯示出來，而GET方法要在URL中顯示；
5、GET方法由于受到URL長度的限制,只能傳遞大約1024字節；POST傳輸的數據量大，可以達到2M，而根據微軟方面的說法，微軟對用 Request.Form() 可接收的最大數據有限制，IIS 4 中為 80 KB 字節，IIS 5 中為 100 KB 字節；
6、SOAP是依賴于HTTP POST模式實現的；
例子：
HTTP GET
發送
GET /DEMOWebServices2.8/Service.asmx/CancelOrder?UserID=string&PWD=string&OrderConfirmation=string HTTP/1.1
Host: api.efxnow.com
回復
HTTP/1.1 200 OK
Content-Type: text/xml; charset=utf-8
Content-Length: length
<?xml version="1.0" encoding="utf-8"?>
<objPlaceOrderResponse xmlns="https://api.efxnow.com/webservices2.3">
<Success>boolean</Success>
<ErrorDescription>string</ErrorDescription>
<ErrorNumber>int</ErrorNumber>
<CustomerOrderReference>long</CustomerOrderReference>
<OrderConfirmation>string</OrderConfirmation>
<CustomerDealRef>string</CustomerDealRef>
</objPlaceOrderResponse>
HTTP POST
發送
POST /DEMOWebServices2.8/Service.asmx/CancelOrder HTTP/1.1
Host: api.efxnow.com
Content-Type: application/x-www-form-urlencoded
Content-Length: length
UserID=string&PWD=string&OrderConfirmation=string
回復
HTTP/1.1 200 OK
Content-Type: text/xml; charset=utf-8
Content-Length: length
<?xml version="1.0" encoding="utf-8"?>
<objPlaceOrderResponse xmlns="https://api.efxnow.com/webservices2.3">
<Success>boolean</Success>
<ErrorDescription>string</ErrorDescription>
<ErrorNumber>int</ErrorNumber>
<CustomerOrderReference>long</CustomerOrderReference>
<OrderConfirmation>string</OrderConfirmation>
<CustomerDealRef>string</CustomerDealRef>
</objPlaceOrderResponse>
SOAP 1.2
發送
POST /DEMOWebServices2.8/Service.asmx HTTP/1.1
Host: api.efxnow.com
Content-Type: application/soap+xml; charset=utf-8
Content-Length: length
<?xml version="1.0" encoding="utf-8"?>
<soap12:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap12="http://www.w3.org/2003/05/soap-envelope">
<soap12:Body>
<CancelOrder xmlns="https://api.efxnow.com/webservices2.3">
<UserID>string</UserID>
<PWD>string</PWD>
<OrderConfirmation>string</OrderConfirmation>
</CancelOrder>
</soap12:Body>
</soap12:Envelope>
回復
HTTP/1.1 200 OK
Content-Type: application/soap+xml; charset=utf-8
Content-Length: length
<?xml version="1.0" encoding="utf-8"?>
<soap12:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap12="http://www.w3.org/2003/05/soap-envelope">
<soap12:Body>
<CancelOrderResponse xmlns="https://api.efxnow.com/webservices2.3">
<CancelOrderResult>
<Success>boolean</Success>
<ErrorDescription>string</ErrorDescription>
<ErrorNumber>int</ErrorNumber>
<CustomerOrderReference>long</CustomerOrderReference>
<OrderConfirmation>string</OrderConfirmation>
<CustomerDealRef>string</CustomerDealRef>
</CancelOrderResult>
</CancelOrderResponse>
</soap12:Body>
</soap12:Envelope>