Web Services：Apache XML-RPC

XML-RPC（http://ws.apache.org/xmlrpc/ ）的全称是XML Remote Procedure Call，即XML远程方法调用。是JAVA实现的XML-RPC。     这种远程过程调用使用http作为传输协议，XML作为传送信息的编码格式。Xml-Rpc的定义尽可能的保持了简单，但同时能够传送、处理、返回复杂的数据结构。 　　XML-RPC是工作在Internet上的远程过程调用协议。一个XML-RPC消息就是一个请求体为xml的http-post请求，被调用的方法在服务器端执行并将执行结果以xml格式编码后返回。 ■All primitive Java types are supported, including long, byte, short, and double.■Calendar objects are supported. In particular, timezone settings, and milliseconds may be sent.■DOM nodes, or JAXB objects, can be transmitted. So are objects implementing the java.io.Serializable interface.■Both server and client can operate in a streaming mode, which preserves resources much better than the default mode, which is based on large internal byte arrays.    概念图如下：  和RMI类似，需要服务器类和客户端类。还需要配置web.xml. 服务器类代码片段：package org.apache.xmlrpc.demo.webserver;   import java.net.InetAddress;  import org.apache.xmlrpc.common.TypeConverterFactoryImpl;  import org.apache.xmlrpc.demo.webserver.proxy.impls.AdderImpl;  import org.apache.xmlrpc.server.PropertyHandlerMapping;  import org.apache.xmlrpc.server.XmlRpcServer;  import org.apache.xmlrpc.server.XmlRpcServerConfigImpl;  import org.apache.xmlrpc.webserver.WebServer;   public class Server {      private static final int port = 8080;       public static void main(String[] args) throws Exception {          WebServer webServer = new WebServer(port);                XmlRpcServer xmlRpcServer = webServer.getXmlRpcServer();                  PropertyHandlerMapping phm = new PropertyHandlerMapping();          /* Load handler definitions from a property file.           * The property file might look like:           *   Calculator=org.apache.xmlrpc.demo.Calculator           *   org.apache.xmlrpc.demo.proxy.Adder=org.apache.xmlrpc.demo.proxy.AdderImpl           */           phm.load(Thread.currentThread().getContextClassLoader(),"MyHandlers.properties");          /* You may also provide the handler classes directly,           * like this:           * phm.addHandler("Calculator",           *     org.apache.xmlrpc.demo.Calculator.class);           * phm.addHandler(org.apache.xmlrpc.demo.proxy.Adder.class.getName(),           *     org.apache.xmlrpc.demo.proxy.AdderImpl.class);           */          xmlRpcServer.setHandlerMapping(phm);           XmlRpcServerConfigImpl serverConfig =               (XmlRpcServerConfigImpl) xmlRpcServer.getConfig();          serverConfig.setEnabledForExtensions(true);          serverConfig.setContentLengthOptional(false);          webServer.start();      }  } web.xml配置片段：<servlet>        <servlet-name>XmlRpcServlet</servlet-name>        <servlet-class>org.apache.xmlrpc.webserver.XmlRpcServlet</servlet-class>        <init-param>          <param-name>enabledForExtensions</param-name>          <param-value>true</param-value>          <description>            Sets, whether the servlet supports vendor extensions for XML-RPC.          </description>        </init-param>    </servlet>    <servlet-mapping>        <servlet-name>XmlRpcServlet</servlet-name>        <url-pattern>/xmlrpc</url-pattern>    </servlet-mapping> 客户端代码片段：package web.service.xml.rpc; import java.net.MalformedURLException;import java.net.URL;import org.apache.xmlrpc.XmlRpcException;import org.apache.xmlrpc.client.XmlRpcClient;import org.apache.xmlrpc.client.XmlRpcClientConfigImpl;import org.apache.xmlrpc.client.XmlRpcCommonsTransportFactory;import org.apache.xmlrpc.client.util.ClientFactory; public class Client {     public static void main(String[] args) throws Exception {        // create configuration        XmlRpcClientConfigImpl config = new XmlRpcClientConfigImpl();        config.setServerURL(new URL("http://127.0.0.1:8080/WEBXMLRPC"));        config.setEnabledForExtensions(true);          config.setConnectionTimeout(60 * 1000);        config.setReplyTimeout(60 * 1000);        XmlRpcClient client = new XmlRpcClient();         // use Commons HttpClient as transport        client.setTransportFactory(            new XmlRpcCommonsTransportFactory(client));         // set configuration        client.setConfig(config);         // make the a regular call        Object[] params = new Object[]            { new Integer(2), new Integer(3) };        Integer result = (Integer) client.execute("calculator_test.add", params);        System.out.println("2 + 3 = " + result);    }} 这里的calculator_test.add关键字是在MyHandlers.properties中配置的。add是方法名。配置例子：calculator_test=web.service.xml.rpc.Calculator Calculator类定义如下：package web.service.xml.rpc; public class Calculator {     public int add(int i1, int i2) {            return i1 + i2;    }    public int subtract(int i1, int i2) {            return i1 - i2;    }}