Spring的WebServiceTemplate访问WebService的方法及其本质原理

WebService客户端调用的本质就是将SAOP格式的XML通过通信协议发送到WebService的服务器端,然后接收服务器端返回的XML.

 

本文简单介绍一下如何通过Spring提供的WebServiceTemplate访问 Webservice,WebServiceTemplate与调用webservice的客户端已及webservice服务器端示意图如下(图片来源 于Spring in Action):

 

 

这里以SOAP over HTTP为例,开发步骤如下:

1,在Spring的配置文件中配置WebServiceTemplate,最简单的配置如下:

    <bean id="webServiceTemplate">  
        <property name="defaultUri" value="http://localhost:8080/prjCXFWS/services/SimpleServicePort"/>  
    </bean>

*这种配置省略了MessageFactory和messageSender的配置,Spring默认会使用SaajSoapMessageFactory和HttpUrlConnectionMessageSender.等同于下面的配置

    <bean id="messageFactory"/>  
    <bean id="webServiceTemplate">  
        <constructor-arg ref="messageFactory"/>  
        <property name="messageSender">  
            <bean/>  
        </property>  
        <property name="defaultUri" value="http://localhost:8080/prjCXFWS/services/SimpleServicePort" />  
    </bean>

还可以使用CommonsHttpMessageSender作为messageSender,它提供了设置timeout,用户名,密码等选项的功能.(需要使用commons-httpclient.jar和commons-codec.jar)
MessageFactory还可以使用AxiomSoapMessageFactory和DomPoxMessageFactory.

    <bean id="webServiceTemplate">  
        <property name="messageSender">  
         <bean>  
          <property name="readTimeout" value="0" />  
         </bean>  
        </property>  
        <property name="defaultUri" value="http://localhost:8080/prjCXFWS/services/SimpleServicePort" />  
    </bean>

2,Java调用代码:传输的是SOAP XML.

    private static final String MESSAGE =  
           "<queryPeopleByID  xmlns=\"http://test.cxfws.com\">1231ss</queryPeopleByID> ";  
    public static void test() {  
        ApplicationContext ac = new ClassPathXmlApplicationContext("conf/wsAppcontext.xml");  
        WebServiceTemplate simpleService = (WebServiceTemplate) ac.getBean("webServiceTemplate");  
        StreamSource source = new StreamSource(new StringReader(MESSAGE));  
           StreamResult result = new StreamResult(System.out);          
           simpleService.sendSourceAndReceiveToResult(source, result);  
    }

*MESSAGE为需要发送到webservice服务器端的XML payload内容,SOAP body之内的XML内容.

Spring调用Webservice的另一种方法是通过Spring提供的JaxWsPortProxyFactoryBean,示意图如下(图片来源于Spring in Action):

Spring的配置如下:

    <bean id="simpleService"  
       >  
        <property name="serviceInterface"  
            value="com.cxfclient.test.SimpleService" />  
        <property name="wsdlDocumentUrl"  
            value="http://localhost:8080/prjCXFWS/services/SimpleServicePort?WSDL" />  
        <property name="namespaceUri" value="http://test.cxfws.com/" />  
        <property name="serviceName" value="SimpleServiceService" />  
        <property name="portName" value="SimpleServicePort" />  
    </bean>

**这种方式需要用工具通过Webservice 的wsdl文件生成客户端需要的一些Java类,如service的interface,参数类等等(如下面代码中的SimpleService,People类).
Java调用代码如下

    ApplicationContext ac = new ClassPathXmlApplicationContext("conf/wsAppcontext.xml");  
    SimpleService simpleService = (SimpleService) ac.getBean("simpleService");  

    People people = simpleService.queryPeopleByID("test");  
    System.out.println(people.getAge() + people.getName() + people.getPid());

关于更多客户端如何调用webservice,参照http://blog.csdn.net/kkdelta/article/details/3987591
对于服务器端,其本质也是接收符合SOAP规范的XML消息,解析XML,返回符合SOAP规范的XML,这里用一个servlet模拟webservice,代码如下:

    public class WSSimulator extends HttpServlet {  
        public void doGet(HttpServletRequest request, HttpServletResponse response)  
        throws IOException {  
            System.out.println("doGet");  
            BufferedReader in = new BufferedReader(new InputStreamReader( request.getInputStream()));  
            String str;  
            while ((str = in.readLine()) != null) {  
                System.out.println(str); ##1  
            }  
            in.close();  

            String soapHeader = "<SOAP-ENV:Envelope xmlns:SOAP-ENV=\"http://schemas.xmlsoap.org/soap/envelope/\">"   
                +"<SOAP-ENV:Header/><SOAP-ENV:Body>";  
            String soapPayload = "<xxx>yyy</xxx>";  
            String soapTail = "</SOAP-ENV:Body></SOAP-ENV:Envelope>";         
            response.getWriter().write(soapHeader + soapPayload + soapTail);  ##2     
        }  
        public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {  
            System.out.println("doPost");  
            doGet(request, response);  
        }  
    }

通过WebServiceTemplate将消息发送到这个servlet监听的url,可以更深理解Webservice的本质.
##1 str就是从客户端传输到服务器端的XML.##2将SOAP消息返回给客户端.
更多服务器端webservice的开发请参照http://blog.csdn.net/kkdelta/article/details/3984312

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