asp.net访问WebService的各种方式
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 = 10000; } /// <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 > 0) { 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, 0, 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, 0, 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。