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

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/xmlrpc"));
        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;
    }
}

 

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