/**
* Dispatches an http request to an open web service (OWS).
* 向OWS开放网络服务转发(派发)http网络请求
* <p>An OWS request contains three bits of information:
* 一个OWS请求包含三点信息：
* <ol>
* <li>The service being called被叫的服务
* <li>The operation of the service to execute执行的服务的操作
* <li>The version of the service ( optional )服务版本(可选)
* </ol>
*
* <p>Additional, an OWS request can contain an arbitray number of additional parameters.
* 另外，一个OWS请求可以包含任意数量的附加参数。
* <p>An OWS request can be specified in two forms. The first form is known as "KVP" in which all
* the parameters come in the form of a set of key-value pairs. Commonly this type of request is
* made in an http "GET" request, the parameters being specified in the query string:
* 一个OWS请求可以用两种方式指定。第一种方式是KVP，其中所有的参数是以键值对的集合形式出现的。通常，
* 这种形式的请求是在一个http的“GET”请求中指定的，参数在查询字符串中指定。
* <pre>
* <code>http://www.xyz.com/geoserver?service=someService&request=someRequest&version=X.Y.Z&param1=...&param2=...</code>
* </pre>
*
* <p>This type of request can also be made in a "POST" request in with a mime-type of
* "application/x-www-form-urlencoded".
* 该类型的请求也能在一个“POST”请求中指定，伴随着mime-type为"application/x-www-form-urlencoded"。
* <p>The second form is known as "XML" in which all the parameters come in the form of an xml
* document. This type of request is made in an http "POST" request.
* 第二种形式称为“XML”，其中所有参数都以XML文件的形式出现。这种类型的请求是在http“POST”请求中发出的。
* <pre><code>
* <?xml version="1.0" encoding="UTF-8"?>
* <SomeRequest service="someService" version="X.Y.Z">
* <Param1>...</Param1>
* <Param2>...</Param2>
* ...
* </SomeRequest>
* </code></pre>
*
* <p>When a request is received, the <b>service</b> the <b>version</b> parameters are used to
* locate a service desciptor, an instance of {@link Service} . With the service descriptor, the
* <b>request</b> parameter is used to locate the operation of the service to call.
*
* @author Justin Deoliveira, The Open Planning Project, jdeolive@openplans.org
*/