tomcat對Http處理：

請求被髮送到本機埠8080，被在那裡偵聽的Coyote HTTP/1.1 Connector獲得
Connector把該請求交給它所在的Service的Engine來處理，並等待Engine的迴應
Engine獲得請求localhost:8080/test/index.jsp，匹配它所有虛擬主機Host
Engine匹配到名為localhost的Host（即使匹配不到也把請求交給該Host處理，因為該Host被定義為該Engine的預設主機）
localhost Host獲得請求/test/index.jsp，匹配它所擁有的所有Context
Host匹配到路徑為/test的Context（如果匹配不到就把該請求交給路徑名為”“的Context去處理）
path=”/test”的Context獲得請求/index.jsp，在它的mapping table中尋找對應的servlet
Context匹配到URL PATTERN為*.jsp的servlet，對應於JspServlet類
構造HttpServletRequest物件和HttpServletResponse物件，作為引數呼叫JspServlet的doGet或doPost方法
Context把執行完了之後的HttpServletResponse物件返回給Host
Host把HttpServletResponse物件返回給Engine
Engine把HttpServletResponse物件返回給Connector
Connector把HttpServletResponse物件返回給客戶browser

pipeline 實現:

    @Override
    public void addValve(Valve valve) {

        // Validate that we can add this Valve
        if (valve instanceof Contained)
            ((Contained) valve).setContainer(this.container);

        // Start the new component if necessary
        if (getState().isAvailable()) {
            if
 
 (valve instanceof Lifecycle) {
                try {
                    ((Lifecycle) valve).start();
                } catch (LifecycleException e) {
                    log.error("StandardPipeline.addValve: start: ", e);
                }
            }
        }

        // basic永遠最後，表示沒有nextValue（）
 

        if (first == null) {
            first = valve;
            valve.setNext(basic);
        } else {
            Valve current = first;
            while (current != null) {
                if (current.getNext() == basic) {
                    current.setNext(valve);
                    valve.setNext(basic);
                    break;
                }
                current = current.getNext();
            }
        }

        container.fireContainerEvent(Container.ADD_VALVE_EVENT, valve);
    }