JFinal 源码导读第五天(2) doFilter中的ActionHandler详解

1.我先贴上doFilter所有代码

	public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest)req;
		HttpServletResponse response = (HttpServletResponse)res;
		request.setCharacterEncoding(encoding);
		
		String target = request.getRequestURI();
		if (contextPathLength != 0)
			target = target.substring(contextPathLength);
		
		boolean[] isHandled = {false};
		try {
			handler.handle(target, request, response, isHandled);
		}
		catch (Exception e) {
			if (log.isErrorEnabled()) {
				String qs = request.getQueryString();
				log.error(qs == null ? target : target + "?" + qs, e);
			}
		}
		
		if (isHandled[0] == false)
			chain.doFilter(request, response);
	}

2.String target = request.getRequestURI();
   if (contextPathLength != 0)
  target = target.substring(contextPathLength);
这两段代码其实就是取出contextPath 留下真是的URI路径
3.handler.handle(target, request, response, isHandled);

4.假如没有配置自己handler那就执行最后面actionHandler

	public final void handle(String target, HttpServletRequest request, HttpServletResponse response, boolean[] isHandled) {
		if (target.indexOf(".") != -1) {
			return ;
		}
		
		isHandled[0] = true;
		String[] urlPara = {null};
		Action action = actionMapping.getAction(target, urlPara);
		
		if (action == null) {
			if (log.isWarnEnabled()) {
				String qs = request.getQueryString();
				log.warn("Action not found: " + (qs == null ? target : target + "?" + qs));
			}
			renderFactory.getErrorRender(404).setContext(request, response).render();
			return ;
		}
		
		try {
			Controller controller = action.getControllerClass().newInstance();
			controller.init(request, response, urlPara[0]);
			
			if (devMode) {
				boolean isMultipartRequest = ActionReporter.reportCommonRequest(controller, action);
				new ActionInvocation(action, controller).invoke();
				if (isMultipartRequest) ActionReporter.reportMultipartRequest(controller, action);
			}
			else {
				new ActionInvocation(action, controller).invoke();
			}
			
			Render render = controller.getRender();
			if (render instanceof ActionRender) {
				String actionUrl = ((ActionRender)render).getActionUrl();
				if (target.equals(actionUrl))
					throw new RuntimeException("The forward action url is the same as before.");
				else
					handle(actionUrl, request, response, isHandled);
				return ;
			}
			
			if (render == null)
				render = renderFactory.getDefaultRender(action.getViewPath() + action.getMethodName());
			render.setContext(request, response, action.getViewPath()).render();
		}
		catch (RenderException e) {
			if (log.isErrorEnabled()) {
				String qs = request.getQueryString();
				log.error(qs == null ? target : target + "?" + qs, e);
			}
		}
		catch (ActionException e) {
			int errorCode = e.getErrorCode();
			if (errorCode == 404) {
				if (log.isWarnEnabled()) {
					String qs = request.getQueryString();
					log.warn("404 Not Found: " + (qs == null ? target : target + "?" + qs));
				}
				e.getErrorRender().setContext(request, response).render();
			}
			else if (errorCode == 401) {
				if (log.isWarnEnabled()) {
					String qs = request.getQueryString();
					log.warn("401 Unauthorized: " + (qs == null ? target : target + "?" + qs));
				}
				e.getErrorRender().setContext(request, response).render();
			}
			else if (errorCode == 403) {
				if (log.isWarnEnabled()) {
					String qs = request.getQueryString();
					log.warn("403 Forbidden: " + (qs == null ? target : target + "?" + qs));
				}
				e.getErrorRender().setContext(request, response).render();
			}
			else {
				if (log.isErrorEnabled()) {
					String qs = request.getQueryString();
					log.error(qs == null ? target : target + "?" + qs, e);
				}
				e.getErrorRender().setContext(request, response).render();
			}
		}
		catch (Exception e) {
			if (log.isErrorEnabled()) {
				String qs = request.getQueryString();
				log.error(qs == null ? target : target + "?" + qs, e);
			}
			renderFactory.getErrorRender(500).setContext(request, response).render();
		}
	}

5.if (target.indexOf(".") != -1) {
   return ;

  }
这几句代码的作用主要就是过滤css,img之类的,让filter不要对它起作用
6.Action action = actionMapping.getAction(target, urlPara);

	/**
	 * Support four types of url
	 * 1: http://abc.com/controllerKey                 ---> 00
	 * 2: http://abc.com/controllerKey/para            ---> 01
	 * 3: http://abc.com/controllerKey/method          ---> 10
	 * 4: http://abc.com/controllerKey/method/para     ---> 11
	 */
	Action getAction(String url, String[] urlPara) {
		Action action = mapping.get(url);
		if (action != null) {
			return action;
		}
		
		// --------
		int i = url.lastIndexOf(SLASH);
		if (i != -1) {
			action = mapping.get(url.substring(0, i));
			urlPara[0] = url.substring(i + 1);
		}
		
		return action;
	}

7. actionMapping我前面已经介绍过啦,在我们的例子里面的值如下：

如果是save方法： 
controllerKey = /blog ,actionKey = /blog/save,controllerClass = BlogController.class,methodName = save,
同理如果是index()方法：
controllerKey=/blog,actionKey=/blog,controllerClass=BlogController.class,methodName =index
同理如果是add()方法：
controllerKey=/blog,actionKey=/blog/add,controllerClass=BlogController.class,methodName=add
同理如果是edit()方法：
controllerKey=/blog,actionKey=/blog/edit,controllerClass= BlogController.class,methodName=edit
同理如果是update()方法：
controllerKey=/blog,actionKey=/blog/update,controllerClass= BlogController.class,methodName=update
同理如果是delete()方法：
controllerKey=/blog,actionKey=/blog/delete,controllerClass= BlogController.class,methodName=delete
6. String controllerKey =entry.getKey();还有在我们中的例子为CommonController中的/
只有1个index方法
controllcontrollerKey=/,actionKey=/,controllerClass=CommonController.class,methodName =index

7.我们的入口是actionKey='/'
Controller controller = action.getControllerClass().newInstance(); // 这句话就可以解释Controller为什么的线程安全的,因为每次都实例化一个新的出来
在我们例子当中是CommonController
controller.init(request, response, urlPara[0]);urlPara就是参数

	void init(HttpServletRequest request, HttpServletResponse response, String urlPara) {
		this.request = request;
		this.response = response;
		this.urlPara = urlPara;
	}

8. ActionReporter.reportCommonRequest(controller, action) 这个就是打印控制台信息的

JFinal action report -------- 2013-06-21 15:13:48 ------------------------------
Controller  : com.demo.common.CommonController.(CommonController.java:1)
Method      : index
Interceptor : com.demo.blog.BlogInterceptor1.(BlogInterceptor1.java:1)
              com.demo.blog.BlogInterceptor2.(BlogInterceptor2.java:1)
--------------------------------------------------------------------------------

9. 这句话是 new ActionInvocation(action, controller).invoke();
就是这里的核心代码，本质就是调用递归调用拦截器

	ActionInvocation(Action action, Controller controller) {
		this.controller = controller;
		this.inters = action.getInterceptors();
		this.action = action;
	}

10.下面的代码就是上面代码的 核心

	/**
	 * Invoke the action.
	 */
	public void invoke() {
		if (index < inters.length)
			inters[index++].intercept(this);
		else if (index++ == inters.length)	// index++ ensure invoke action only one time
			// try {action.getMethod().invoke(controller, NULL_ARGS);} catch (Exception e) {throw new RuntimeException(e);}
			try {
				action.getMethod().invoke(controller, NULL_ARGS);
			}
			catch (InvocationTargetException e) {
				Throwable cause = e.getTargetException();
				if (cause instanceof RuntimeException)
					throw (RuntimeException)cause;
				throw new RuntimeException(e);
			}
			catch (RuntimeException e) {
				throw e;
			}
			catch (Exception e) {
				throw new RuntimeException(e);
			}
	}

这张图片就是上面代码执行的核心,也是拦截器的核心

Before invoking BlogInterceptor1/
Before invoking BlogInterceptor2/
执行CommonController里面index方法
After invoking BlogInterceptor2/
After invoking BlogInterceptor1/

11.Render render = controller.getRender();
就是上面所说的FreeMarkerRenderFactory. getRender()
12.render.setContext(request, response, action.getViewPath()).render();

	public void render() {
		response.setContentType(contentType);
        Enumeration<String> attrs = request.getAttributeNames();
		Map root = new HashMap();
		while (attrs.hasMoreElements()) {
			String attrName = attrs.nextElement();
			root.put(attrName, request.getAttribute(attrName));
		}
		
		PrintWriter writer = null;
        try {
			Template template = config.getTemplate(view);
			writer = response.getWriter();
			template.process(root, writer);		// Merge the data-model and the template
		} catch (Exception e) {
			throw new RenderException(e);
		}
		finally {
			if (writer != null)
				writer.close();
		}
	}

一个流程完全结束下面,下一个阶段我会介绍数据库方面的啦,最后我会扩展权限功能.....