架构设计-总控

     架构设计的核心是总控，本文参考Struts框架，撰写简单的MVC模型。

　　先看配置信息，该配置信息描述每个请求所使用的Action及响应的视图。

<requests>
    <request path="/default.do" action="org.heroking.web.action.DefaultAction" view="/default.jsp"/>
</requests>

    在web.xml中配置总控Servlet配置信息   

 

<servlet>
      <servlet-name>default-servlet</servlet-name>
      <servlet-class>org.heroking.web.servlet.DefaultServlet</servlet-class>
      <init-param>
          <param-name>config-file</param-name>
          <param-value>/WEB-INF/request.xml</param-value>
      </init-param>
  </servlet>
  <servlet-mapping>
      <servlet-name>default-servlet</servlet-name>
      <url-pattern>*.do</url-pattern>
  </servlet-mapping>

  在总控的Servlet的init（）函数中，我们要加载该配置文件，代码如下：

@Override
    public void init() throws ServletException {
        // TODO Auto-generated method stub
        super.init();
        log.debug("into DefaultServlet init()");
        SAXBuilder builder = new SAXBuilder(false);
        try {
            Document doc = builder.build(this.getServletContext().getRealPath(this.getInitParameter("config-file")));
            Element e = doc.getRootElement();
            List requestList=e.getChildren("request");
            for (Iterator iter = requestList.iterator(); iter.hasNext();) {
                Element request = (Element)iter.next();
                RequestConfig r = new RequestConfig();
                r.setPath(request.getAttributeValue("path"));
                r.setAction(request.getAttributeValue("action"));
                r.setView(request.getAttributeValue("view"));
                if (!requests.containsKey(r.getPath()))
                {
                    requests.put(r.getPath(), r);
                }
            }
        } catch (JDOMException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            log.debug(e.getMessage());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            log.debug(e.getMessage());
        }
    }

 

servlet的请求解析函数如下：

/** *//**
     * 请求解析
     * @param req
     * @param resp
     */
    private void execute(HttpServletRequest req, HttpServletResponse resp)
    {
        if (requests.containsKey(req.getServletPath())) {
            try {
                RequestConfig rc = requests.get(req.getServletPath());
                IAction action = (IAction)Thread.currentThread().getContextClassLoader().loadClass(rc.getAction()).newInstance();
                action.execute(req, resp);
                RequestDispatcher rd = this.getServletContext().getRequestDispatcher(rc.getView());
                rd.forward(req, resp);
                return;
            } catch (InstantiationException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                log.debug(e.getMessage());
            } catch (IllegalAccessException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                log.debug(e.getMessage());
            } catch (ClassNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                log.debug(e.getMessage());
            } catch (ServletException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                log.debug(e.getMessage());
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                log.debug(e.getMessage());
            }
            
        }
                
    }

 

为了便于统一管理，我们定义统一的IAction接口，代码如下：

/** *//**
 * 
 * @author Hero King
 *
 */
public interface IAction {
    /** *//**
     * 执行Action
     * @param request
     * @param response
     */
    void execute(HttpServletRequest request, HttpServletResponse response);
}