xmlhttp对象调用webservice要点补疑

使用xmlhttp对象调用非本地webservice经常也遇到调用失败的情况,这应该是一个不断总结的过程.现列举我所经历过的困扰多时的细节错误,
假定一个天气预报的服务如下:

using System;

using System.Web;

using System.Web.Services;

using System.Web.Services.Protocols;

[WebService(Namespace = "http://tempuri.org/")]

[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

public class Weather : System.Web.Services.WebService

{

public Weather () {

//Uncomment the following line if using designed components

//InitializeComponent();

}

[WebMethod]

public string GetWeather(string cityName) {

//根据城市名来返回天气情况

return "Sunny";

}

         1. 请求的方法根据协议有Soap 1.1 Soap1.2 HttpPost HttpGet 四种方式

         (1)SOAP 1.1

var data ='<?xml version="1.0" encoding="utf-8"?>'

+'<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:Body>'

+'<getWeather xmlns="http://tempuri.org/">'

+'<cityName>hangzhou</cityName>'

+'</getWeather>'

+'</soap:Body>'

+'</soap:Envelope>'

function RequestService(){

var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");

//Webservice location.

var URL="http://localhost:1323/WebSite/weather.asmx";

xmlhttp.Open("Post",URL, false);

xmlhttp.SetRequestHeader ("Content-Type","text/xml; charset=utf-8");

xmlhttp.SetRequestHeader ("Content-Length",data.length);

xmlhttp.SetRequestHeader ("SOAPAction","http://tempuri.org/GetWeather");

xmlhttp.Send(data);

}

(2)SOAP 1.2

var data = '<?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>'

+'<getWeather xmlns="http://tempuri.org/">'

+'<cityName>hangzhou</cityName>'

+'</getWeather>'

+'</soap12:Body>'

+'</soap12:Envelope>'

function RequestService(){

var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");

//Webservice location.

var URL="http://localhost:1323/WebSite/weather.asmx";

xmlhttp.Open("Post",URL, false);

xmlhttp.SetRequestHeader ("Content-Type"," application/soap+xml; charset=utf-8");

xmlhttp.SetRequestHeader ("Content-Length",data.length);

xmlhttp.Send(data);

}

(3)HttpPost

var data = 'cityName=hangzhou'

function RequestService(){

var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");

//Webservice location.

var URL="http://localhost:1323/WebSite/weather.asmx/getWeather";

xmlhttp.Open("Post",URL, false);

xmlhttp.SetRequestHeader ("Content-Type"," application/x-www-form-urlencoded");

xmlhttp.SetRequestHeader ("Content-Length",data.length);

xmlhttp.Send(data);

}

         (4)HttpGet

function RequestService(){

var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");

//Webservice location.

var URL="http://localhost:1323/WebSite/weather.asmx/getWeather?cityName=hangzhou";

xmlhttp.Open("GET ",URL, false);

xmlhttp.Send(null);

}

         2.中文乱码
         webservice接收和传输的消息都是UTF-8编码的，网上有很多解决GB2312传中文参数和接收中文消息乱码的办法，比如用prototype扩展xmlhttp对象,其实也不用那么麻烦,传递参数用escape转换一次,接收时用UTF8Encoding读取出来再根据需要转换即可,解决办法原理差不多.

         3.解析返回的Xml DomDocument对象无法使用selectNodes和selectSingleNode
          其中一个原因是mozilla不支持此方法，可以通过prototype为它的domdocument对象扩展这两个同名方法，便于用相同的方法处理MS和mozilla兼容问题。但有时就是在IE里也不能正常使用这两个方法，常见情况是取出来的节点值为空。解决办法是在生成的domdocument对象（假设对象为xmlDom）设置一个属性 xmlDom.setProerty("Namespace",'xmlns="na:http://tempuri.org/"')指定一个默认命名空间的前缀,然后在selectNodes和selectSingleNode中使用前缀加标签名如 na:weather就可以了。

          4.“意外的以servicemethod/结尾“的错误(类似的格式)
          客户端以HttpGet或HttpPost方式调用非本地webservice报“意外的以servicemethod/结尾“的错误，其中一个原因是部署webservice的站点配置中默认是不开启httpget和httppost非本域请求许可的，因此要在web.config补上如下配置

</conformanceWarnings>

</protocols>

</soapExtensionTypes>

</soapExtensionReflectorTypes>

</soapExtensionImporterTypes>

</serviceDescriptionFormatExtensionTypes>

</webServices>

希望打算使用xmlhttp的朋友能够避免这些小问题,也希望大家能够将自己遇到的问题和解决方法继续补全，方便查找也提高自己。上面列举的问题如有更易行的方法，也请指出来，交流一下。