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;
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[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class Weather : System.Web.Services.WebService
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{
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public Weather ()
{
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//Uncomment the following line if using designed components
//InitializeComponent();
}
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[WebMethod]
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public string GetWeather(string cityName)
{
//根据城市名来返回天气情况
return "Sunny";
}
}
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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>'
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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);
}
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(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>'
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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);
}
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(3)HttpPost
var data = 'cityName=hangzhou'
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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);
}
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(4)HttpGet
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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);
}
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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
<webServices>
<conformanceWarnings>
<clear />
<add name="BasicProfile1_1" />
</conformanceWarnings>
<protocols>
<add name="HttpSoap1.2"/>
<add name="HttpSoap"/>
<add name="HttpPostLocalhost"/>
<add name="HttpPost"/>
<add name="HttpGet"/>
<add name="Documentation"/>
</protocols>
<soapExtensionTypes>
</soapExtensionTypes>
<soapExtensionReflectorTypes>
</soapExtensionReflectorTypes>
<soapExtensionImporterTypes>
</soapExtensionImporterTypes>
<wsdlHelpGenerator href="DefaultWsdlHelpGenerator.aspx"/>
<serviceDescriptionFormatExtensionTypes>
</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。