对petsore的ControllerServlet类的分析

     最近看看了PETSTORE2.0的一些代码，发现有很多东西值得学习。

      下面我来分析一下ControllerServlet这个SERVLET，它位于com.sun.javaee.blueprints.petstore.controller包之中。它的作用是根据请求的SERVLET的URi完成不同的特定功能，我只看了产生随机图片的那个调用。

代码如下：

/**
 * This servlet is responsible for interacting with a client
 * based controller and will fetch resources including content
 * and relevant script.
 *
 * This servlet also will process requests for client ob
servers
 */
public class ControllerServlet extends HttpServlet {

    private static final boolean bDebug=false;
    private HashMap<String, ControllerAction> actionMap = new HashMap<String, ControllerAction>();

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        ServletContext context = config.getServletContext();
        CatalogFacade cf = (CatalogFacade) context.getAttribute("CatalogFacade");
        actionMap.put("/ImageServlet", new ImageAction(context));
        actionMap.put("/controller", new DefaultControllerAction(context));
        actionMap.put("/faces/CaptchaServlet", new CaptchaAction());
        actionMap.put("/TagServlet", new TagXmlAction(cf));
        actionMap.put("/catalog", new CatalogXmlAction(cf));
    }

    public ControllerAction findAction(String servletPath) {
        return actionMap.get(servletPath);
    }
    @Override
    public void destroy() {
        actionMap = null;
    }

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String servletPath = request.getServletPath();
        if(bDebug) System.out.println(" ServletPath: " + servletPath + ", pathinfo: " + request.getPathInfo());
        ControllerAction action = actionMap.get(servletPath);
        if (action != null) {
            if(bDebug) System.out.println(" Found action " + action.getClass().getName());
            action.service(request, response);
        } else {
            PetstoreUtil.getLogger().log(Level.SEVERE, "Servlet '" + request.getServletPath() + "' not registered in ControllerServlet!!");
            HttpServletResponse httpResponse=(HttpServletResponse)response;
            httpResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
        }
    }
}

它的运作流程可以很容易的看出来：首先SERVLET加载入所有需要处理的servlet URI，把他们都存入一个HASHmAP当中，然后在DOGET中，读取请求的SERVLET的RUI，得到特定的URI后就进行相应的操作。

 

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• 2007-10-07 11:36
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