1. JFinalFilter类doFilter 请求入口

   将请求交由Handler链处理

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();//请求路径if (contextPathLength != 0)target = target.substring(contextPathLength);//截去请求的IP域名部分boolean[] isHandled = {false};try {handler.handle(target, request, response, isHandled);//交由Handler链处理}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.MyHandler类 自定义的handler类，在handler里加入自己的方法比如：网站改版，需要在新网站上兼容老网站上的url时能用到，只需要在Handler中将老网站url转换成新的就可以了。在处理完之后必须加上nextHandler.handle(target, request, response, isHandled);这样才能遍历到我们添加的handler类。JFinal的Handler是AOP+责任链模式的一个变种。

public class MyHandler extends Handler{@Overridepublic void handle(String target, HttpServletRequest request,HttpServletResponse response, boolean[] isHandled) {System.out.println("-----myhandler is working-----");nextHandler.handle(target, request, response, isHandled);        }
}

3.ActionHandler类 添加在handler链的尾部，封装了对action及interceptor的处理

• Action action = actionMapping.getAction(target)//actionMapping是我们在初始化过程中将请求的URL-处理Action保存在map中，以URL作为key，Action作为value。而Action中封装着处理请求的controller类，method方法等

• Controller controller = action.getControllerClass().newInstance();通过action的保存的controller类用反射的方法得到controller实例

• new ActionInvocation(action, controller).invoke();执行controller的method方法，最后通过调用renderxxx方法，生成对应的响应，保存到controller的render属性上

    /*** handle* 1: Action action = actionMapping.getAction(target)* 2: new ActionInvocation(...).invoke()* 3: render(...)*/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) {//请求没有找到对应的处理类，返回404if (log.isWarnEnabled()) {String qs = request.getQueryString();log.warn("404 Action Not Found: " + (qs == null ? target : target + "?" + qs));}renderFactory.getErrorRender(404).setContext(request, response).render();//返回404页面return ;}try {Controller controller = action.getControllerClass().newInstance();//通过反射得到controller实例controller.init(request, response, urlPara[0]);//初始化controller类if (devMode) {//调试模式boolean isMultipartRequest = ActionReporter.reportCommonRequest(controller, action);//打印请求信息new ActionInvocation(action, controller).invoke();if (isMultipartRequest) ActionReporter.reportMultipartRequest(controller, action);}else {new ActionInvocation(action, controller).invoke();}Render render = controller.getRender();//取得controller的render属性if (render instanceof ActionRender) {//如果是ActionRender则作为新的请求处理String actionUrl = ((ActionRender)render).getActionUrl();if (target.equals(actionUrl))throw new RuntimeException("The forward action url is the same as before.");elsehandle(actionUrl, request, response, isHandled);//处理ActionRender.getActionUrlreturn ;}if (render == null)//如果render为空则返回默认的页面render = renderFactory.getDefaultRender(action.getViewPath() + action.getMethodName());render.setContext(request, response, action.getViewPath()).render();// 最后最终 可以返回给客户端了 Render to client  }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 && log.isWarnEnabled()) {String qs = request.getQueryString();log.warn("404 Not Found: " + (qs == null ? target : target + "?" + qs));}else if (errorCode == 401 && log.isWarnEnabled()) {String qs = request.getQueryString();log.warn("401 Unauthorized: " + (qs == null ? target : target + "?" + qs));}else if (errorCode == 403 && log.isWarnEnabled()) {String qs = request.getQueryString();log.warn("403 Forbidden: " + (qs == null ? target : target + "?" + qs));}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();}}

4.ActionInvocation类 通过反射执行method，得到返回给客户端的render实例

  /*** Invoke the action.*/public void invoke() {if (index < inters.length)inters[index++].intercept(this);    //先执行拦截器，在执行具体方法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);//通过反射执行controller的method方法，进行对应的操作，然后调用render系列方法，render方法中使用工厂模式实例化render类，保存到controller的render属性上。}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);}}