WebService的访问形式主要有：SOAP调用、XMLHTTP POST、GET调用、MicroSoft.XMLDOMC调用、webbehavior.htc调用
我们知道的在C#后台本地调用Webservice最简单、快捷的调用WebService的方法即通过鼠标手动添加web服务引用的方式。实际操作中我们会使用到另外一种方式，即通过HttpWebRequest构造请求。这种方式下以Post和Get两种请求为主，另外还有通用方式调用。一共三种。下面我们来看实际操作的实现方法。
由于这三种方式在实现原理上是相似的。只是具体的方式不同（哈哈，我的表述不是很专业，能理解是怎么回事就行）。于是我们抽象出公共的基类:WebServiceCaller
/// <summary>
/// 访问webservice基类
/// </summary>
public abstract class WebServiceCaller
{
/// <summary>
/// 请求WebService
/// </summary>
/// <param name="URL">WebService的路径</param>
/// <param name="MethodName">方法名</param>
/// <param name="Pars">参数</param>
/// <returns></returns>
abstract public System.Xml.XmlDocument RequestWebService(ResquestParams rp); /// <summary>
/// 设置凭证与超时时间
/// </summary>
/// <param name="request"></param>
public static void SetWebRequest(HttpWebRequest request)
{
request.Credentials = CredentialCache.DefaultCredentials;
request.Timeout = ;
} /// <summary>
/// 读取响应输出流
/// </summary>
/// <param name="response"></param>
/// <returns></returns>
public 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;
} public static String ParsToString(Hashtable Pars)
{
StringBuilder sb = new StringBuilder();
foreach (string k in Pars.Keys)
{
if (sb.Length > )
{
sb.Append("&");
}
sb.Append(HttpUtility.UrlEncode(k) + "=" + HttpUtility.UrlEncode(Pars[k].ToString()));
}
return sb.ToString();
}
}
Post方式调用Webservice类的实现代码:
/// <summary>
/// Post方式访问
/// </summary>
public class WebServiceCallerByPost : WebServiceCaller
{
public override XmlDocument RequestWebService(ResquestParams rp)
{
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(rp.URL + "/" + rp.MethodName);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
SetWebRequest(request);
byte[] data = EncodePars(rp.Parames);
WriteRequestData(request, data);
return ReadXmlResponse(request.GetResponse());
} /// <summary>
/// 参数编码
/// </summary>
/// <param name="Pars"></param>
/// <returns></returns>
private static byte[] EncodePars(Hashtable Pars)
{
return Encoding.UTF8.GetBytes(ParsToString(Pars));
} /// <summary>
/// 添加请求参数
/// </summary>
/// <param name="request"></param>
/// <param name="data"></param>
private static void WriteRequestData(HttpWebRequest request, byte[] data)
{
request.ContentLength = data.Length;
System.IO.Stream writer = request.GetRequestStream();
writer.Write(data, , data.Length);
writer.Close();
} }
Get方式调用Webservice类的实现代码:
/// <summary>
/// Get方式访问
/// </summary>
public class WebServiceCallerByGet : WebServiceCaller
{
public override XmlDocument RequestWebService(ResquestParams rp)
{
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(rp.URL + "/" + rp.MethodName + "?" + ParsToString(rp.Parames));
request.Method = "GET";
request.ContentType = "application/x-www-form-urlencoded";
SetWebRequest(request);
return ReadXmlResponse(request.GetResponse());
}
}
通用方式调用Webservice类的实现代码:
/// <summary>
/// 通用方式调用webservice
/// </summary>
public class SoapWebService : WebServiceCaller
{ public override XmlDocument RequestWebService(ResquestParams rp)
{
if (_xmlNamespaces.ContainsKey(rp.URL))
{
return QuerySoapWebService(rp.URL, rp.MethodName, rp.Parames, _xmlNamespaces[rp.URL].ToString());
}
else
{
return QuerySoapWebService(rp.URL, rp.MethodName, rp.Parames, GetNamespace(rp.URL));
}
} private static XmlDocument QuerySoapWebService(String URL, String MethodName, Hashtable Pars, string XmlNs)
{
_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();
System.IO.StreamReader sr = new System.IO.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_x_x("soap", "Body", "http://schemas.xmlsoap.org/soap/envelope/");
XmlElement soapBody = doc.CreateElement("soap", "Body", "http://schemas.xmlsoap.org/soap/envelope/");
//XmlElement soapMethod = doc.createElement_x_x(MethodName);
XmlElement soapMethod = doc.CreateElement(MethodName);
soapMethod.SetAttribute("xmlns", XmlNs);
foreach (string k in Pars.Keys)
{
//XmlElement soapPar = doc.createElement_x_x(k);
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 void WriteRequestData(HttpWebRequest request, byte[] data)
{
request.ContentLength = data.Length;
System.IO.Stream writer = request.GetRequestStream();
writer.Write(data, , data.Length);
writer.Close();
} private static void AddDelaration(XmlDocument doc)
{
XmlDeclaration decl = doc.CreateXmlDeclaration("1.0", "utf-8", null);
doc.InsertBefore(decl, doc.DocumentElement);
} 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 Hashtable _xmlNamespaces = new Hashtable();//缓存xmlNamespace，避免重复调用GetNamespace
在编码调用时可以考虑设计一个请求参数类
public class ResquestParams
{
/// <summary>
/// WebService地址
/// </summary>
public string URL { get; set; }
/// <summary>
/// web方法
/// </summary>
public string MethodName { get; set; }
/// <summary>
/// 方法参数
/// </summary>
public Hashtable Parames { get; set; }
}
另外我们在aspx前台页面也会通过js代码来调用Webservice。此处略带"串烧"一下
$.post():
$(document).ready(function () {
$("#btnRequest").click(function () {
$.ajax({
type: "post",
contentType: "application/json",
url: "http://localhost:5158/TestWebService.asmx/Add",
data: "{m:12,n:2}", //注意区别于get方式的参数格式
datatype: "json",
error: function (x, e) {
alert(x.responseText);
},
success: function (result) {
alert(result.d);
}
});
});
});$.get():
$(document).ready(function () {
$("#btnRequest").click(function () {
$.ajax({
type: "get",
contentType: "application/json",
url: "http://localhost:5158/TestWebService.asmx/Add",
data: {'m':'12','n':'2'},
datatype: "json",
error: function (x, e) {
alert(x.responseText);
},
success: function (result) {
alert(result.d);
}
});
});
});注1：如果采用以上HTTP GET方式在后台访问WebService总是报500异常的话，那么很可能是你需要在WebService所在的站点下的配置文件中加上如下配置：
<webServices>
<protocols>
<add name= "HttpPost " />
<add name= "HttpGet " />
</protocols>
</webServices>
注2：如果以上通过ajax.get()方式访问WebService时候提示这样的错误：尝试使用GET请求调用方法xx，但是不允许这样做。那么就是所调用的方法不支持脚本通过GET方式调用，需要在所调用的方法加上[ScriptMethod(UseHttpGet=true)]就ok了。
这里仅仅介绍如何消费WebService，其实要完整地学习它，我们还要了解它的历史沿革。好了就介绍到这儿。