Net 下采用GET/POST/SOAP方式动态调用WebService C#实现
一直以来，我们都为动态调用WebService方法而烦恼。在.Net环境下，最常用的方法就是采用代理类来调用WebService，可以通过改变代理类的Url属性来实现动态调用，但当xmlns改变时就会出错，似乎要重新绑定Webservice并重新编译后才能再次运行。我无意中通过百度搜索找了一个采用GET/POST/SOAP方式动态调用WebService的简易灵活方法，只需传入WebService地址、需调用的方法及其参数，就可以随时动态调用了。经过测试调用成功，现分享给大家，代码如下：
using System;
using System.Web;
using System.Xml;
using System.Collections;
using System.Net;
using System.Text;
using System.IO;
using System.Xml.Serialization;
//By huangz 2008-3-19
/**//// <summary>
/// 利用WebRequest/WebResponse进行WebService调用的类,By 同济黄正 http://hz932.ys168.com 2008-3-19
/// </summary>
public class WebSvcCaller
{
//<webServices>
// <protocols>
// <add name="HttpGet"/>
// <add name="HttpPost"/>
// </protocols>
//</webServices>
private static Hashtable _xmlNamespaces = new Hashtable();//缓存xmlNamespace，避免重复调用GetNamespace
/**//// <summary>
/// 需要WebService支持Post调用
/// </summary>
public static XmlDocument QueryPostWebService(String URL , String MethodName , Hashtable Pars)
{
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(URL + "/" + MethodName);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
SetWebRequest(request);
byte[] data = EncodePars(Pars);
WriteRequestData(request , data);
return ReadXmlResponse(request.GetResponse());
}
/**//// <summary>
/// 需要WebService支持Get调用
/// </summary>
public static XmlDocument QueryGetWebService(String URL , String MethodName , Hashtable Pars)
{
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(URL + "/" + MethodName + "?" + ParsToString(Pars));
request.Method = "GET";
request.ContentType = "application/x-www-form-urlencoded";
SetWebRequest(request);
return ReadXmlResponse(request.GetResponse());
}
/**//// <summary>
/// 通用WebService调用(Soap),参数Pars为String类型的参数名、参数值
/// </summary>
public static XmlDocument QuerySoapWebService(String URL , String MethodName , Hashtable Pars)
{
if (_xmlNamespaces.ContainsKey(URL))
{
return QuerySoapWebService(URL , MethodName , Pars , _xmlNamespaces[URL].ToString());
}
else
{
return QuerySoapWebService(URL , MethodName , Pars ,GetNamespace(URL));
}
}
private static XmlDocument QuerySoapWebService(String URL , String MethodName , Hashtable Pars , string XmlNs)
{ //By 同济黄正 http://hz932.ys168.com 2008-3-19
_xmlNamespaces[URL] = XmlNs;//加入缓存，提高效率
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(URL);
request.Method = "POST";
request.ContentType = "text/xml; charset=utf-8";
request.Headers.Add("SOAPAction" , "\"" + XmlNs + (XmlNs.EndsWith("/") ? "" : "/") + MethodName + "\"");
SetWebRequest(request);
byte[] data = EncodeParsToSoap(Pars , XmlNs , MethodName);
WriteRequestData(request , data);
XmlDocument doc = new XmlDocument() , doc2 = new XmlDocument();
doc = ReadXmlResponse(request.GetResponse());
XmlNamespaceManager mgr = new XmlNamespaceManager(doc.NameTable);
mgr.AddNamespace("soap" , "http://schemas.xmlsoap.org/soap/envelope/");
String RetXml = doc.SelectSingleNode("//soap:Body/*/*" , mgr).InnerXml;
doc2.LoadXml("<root>" + RetXml + "</root>");
AddDelaration(doc2);
return doc2;
}
private static string GetNamespace(String URL)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL + "?WSDL");
SetWebRequest(request);
WebResponse response = request.GetResponse();
StreamReader sr = new StreamReader(response.GetResponseStream() , Encoding.UTF8);
XmlDocument doc = new XmlDocument();
doc.LoadXml(sr.ReadToEnd());
sr.Close();
return doc.SelectSingleNode("//@targetNamespace").Value;
}
private static byte[] EncodeParsToSoap(Hashtable Pars , String XmlNs , String MethodName)
{
XmlDocument doc = new XmlDocument();
doc.LoadXml("<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\"></soap:Envelope>");
AddDelaration(doc);
XmlElement soapBody = doc.CreateElement("soap" , "Body" , "http://schemas.xmlsoap.org/soap/envelope/");
XmlElement soapMethod = doc.CreateElement(MethodName);
soapMethod.SetAttribute("xmlns" , XmlNs);
foreach (string k in Pars.Keys)
{
XmlElement soapPar = doc.CreateElement(k);
soapPar.InnerXml = ObjectToSoapXml(Pars[k]);
soapMethod.AppendChild(soapPar);
}
soapBody.AppendChild(soapMethod);
doc.DocumentElement.AppendChild(soapBody);
return Encoding.UTF8.GetBytes(doc.OuterXml);
}
private static string ObjectToSoapXml(object o)
{
XmlSerializer mySerializer = new XmlSerializer(o.GetType());
MemoryStream ms=new MemoryStream();
mySerializer.Serialize(ms,o);
XmlDocument doc=new XmlDocument();
doc.LoadXml(Encoding.UTF8.GetString(ms.ToArray()));
if(doc.DocumentElement !=null)
{
return doc.DocumentElement.InnerXml ;
}
else
{
return o.ToString();
}
}
private static void SetWebRequest(HttpWebRequest request)
{
request.Credentials = CredentialCache.DefaultCredentials;
request.Timeout = 10000;
}
private static void WriteRequestData(HttpWebRequest request , byte[] data)
{
request.ContentLength = data.Length;
Stream writer = request.GetRequestStream();
writer.Write(data , 0 , data.Length);
writer.Close();
}
private static byte[] EncodePars(Hashtable Pars)
{
return Encoding.UTF8.GetBytes(ParsToString(Pars));
}
private static String ParsToString(Hashtable Pars)
{
StringBuilder sb = new StringBuilder();
foreach (string k in Pars.Keys)
{
if (sb.Length > 0)
{
sb.Append("&");
}
sb.Append(HttpUtility.UrlEncode(k) + "=" + HttpUtility.UrlEncode(Pars[k].ToString()));
}
return sb.ToString();
}
private static XmlDocument ReadXmlResponse(WebResponse response)
{
StreamReader sr = new StreamReader(response.GetResponseStream() , Encoding.UTF8);
String retXml = sr.ReadToEnd();
sr.Close();
XmlDocument doc = new XmlDocument();
doc.LoadXml(retXml);
return doc;
}
private static void AddDelaration(XmlDocument doc)
{
XmlDeclaration decl = doc.CreateXmlDeclaration("1.0" , "utf-8" , null);
doc.InsertBefore(decl , doc.DocumentElement);
}
}
这个类有三个公用的方法：QuerySoapWebService为通用的采用Soap方式调用WebService，QueryGetWebService采用GET方式调用，QueryPostWebService采用POST方式调用，后两个方法需要WebService服务器支持相应的调用方式。三个方法的参数和返回值相同：URL为Webservice的Url地址(以.asmx结尾的)；MethodName为要调用的方法名称；Pars为参数表，它的Key为参数名称，Value为要传递的参数的值,Value可为任意对象，前提是这个对象可以被xml序列化。注意方法名称、参数名称、参数个数必须完全匹配才能正确调用。第一次以Soap方式调用时，因为需要查询WSDL获取xmlns，因此需要时间相对长些，第二次调用不用再读WSDL，直接从缓存读取。这三个方法的返回值均为XmlDocument对象，这个返回的对象可以进行各种灵活的操作。最常用的一个SelectSingleNode方法，可以让你一步定位到Xml的任何节点，再读取它的文本或属性。也可以直接调用Save保存到磁盘。采用Soap方式调用时，根结点名称固定为root。
这个类主要是利用了WebRequest/WebResponse来完成各种网络查询操作。为了精简明了，这个类中没有添加错误处理，需要在调用的地方设置异常捕获。
下面是一个调用实例：
protected void Page_Load(object sender , EventArgs e)
{
try
{
Hashtable pars = new Hashtable();
String Url = "http://www.260dns.cn/Services/Weather.asmx";
pars["city"] = "上海";
pars["wdate"]="2008-3-19";
XmlDocument doc = WebSvcCaller.QuerySoapWebService(Url , "GetWeather" , pars);
Response.Write(doc.OuterXml);
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
}
