how tomcat works 总结 二

标签：tomcat   读书笔记   valve   components   

第五章 servlet容器

第一部分 wrapper

public class SimpleWrapper implements Wrapper, Pipeline {

  // the servlet instance
  private Servlet instance = null;
  private String servletClass;
  private Loader loader;
  private String name;
  private SimplePipeline pipeline = new SimplePipeline(this);
  protected Container parent = null;
    public SimpleWrapper() {
    pipeline.setBasic(new SimpleWrapperValve());
  }

  public synchronized void addValve(Valve valve) {
    pipeline.addValve(valve);
  }
  ...
}

SimpleWrapper.java
  public void invoke(Request request, Response response)
    throws IOException, ServletException {
    pipeline.invoke(request, response);
  }

SimplePipeline.java
    public void invoke(Request request, Response response)
    throws IOException, ServletException {
    // Invoke the first Valve in this pipeline for this request
    (new SimplePipelineValveContext()).invokeNext(request, response);
  }
  SimplePipelineValveContext为SimplePipeline的内部类,作用就是循环所有的阀,最后调用基础阀(就是下面代码中的basic)
  SimplePipelineValveContext.java
   public void invokeNext(Request request, Response response)
      throws IOException, ServletException {
      int subscript = stage;
      stage = stage + 1;
      // Invoke the requested Valve for the current request thread
      if (subscript < valves.length) {
        valves[subscript].invoke(request, response, this);
      }
      else if ((subscript == valves.length) && (basic != null)) {
        basic.invoke(request, response, this);
      }
      else {
        throw new ServletException("No valve");
      }
    }

 第二部分 context

 public Container map(Request request, boolean update) {

    String requestURI = ((HttpRequest) request).getDecodedRequestURI();
    String relativeURI = requestURI.substring(contextPath.length());

    Wrapper wrapper = null;

    String name = context.findServletMapping(relativeURI);
    if (name != null)
      wrapper = (Wrapper) context.findChild(name);
    return (wrapper);
  }

第六章 生命周期

public synchronized void start() throws LifecycleException {
    if (started)
      throw new LifecycleException("SimpleContext has already started");

    // Notify our interested LifecycleListeners
    lifecycle.fireLifecycleEvent(BEFORE_START_EVENT, null);
    started = true;
    try {
      // Start our subordinate components, if any
      if ((loader != null) && (loader instanceof Lifecycle))
        ((Lifecycle) loader).start();

      // Start our child containers, if any
      Container children[] = findChildren();
      for (int i = 0; i < children.length; i++) {
        if (children[i] instanceof Lifecycle)
          ((Lifecycle) children[i]).start();
      }

      // Start the Valves in our pipeline (including the basic),
      // if any
      if (pipeline instanceof Lifecycle)
        ((Lifecycle) pipeline).start();
      // Notify our interested LifecycleListeners
      lifecycle.fireLifecycleEvent(START_EVENT, null);
    }
    catch (Exception e) {
      e.printStackTrace();
    }

Bootstrap.java
    LifecycleListener listener = new SimpleContextLifecycleListener();
    ((Lifecycle) context).addLifecycleListener(listener);

simplecontext.java
protected LifecycleSupport lifecycle = new LifecycleSupport(this);

public void addLifecycleListener(LifecycleListener listener) {
    lifecycle.addLifecycleListener(listener);
  }

 lifecycle.fireLifecycleEvent(BEFORE_START_EVENT, null);
LifecycleSupport.java
  public void fireLifecycleEvent(String type, Object data) {

        LifecycleEvent event = new LifecycleEvent(lifecycle, type, data);
        LifecycleListener interested[] = null;
        synchronized (listeners) {
            interested = (LifecycleListener[]) listeners.clone();
        }
        for (int i = 0; i < interested.length; i++)      //循环通知所有关注者
            interested[i].lifecycleEvent(event);
    }

// 一个具体的关注者
public class SimpleContextLifecycleListener implements LifecycleListener {

  @SuppressWarnings("unused")
public void lifecycleEvent(LifecycleEvent event) {
    Lifecycle lifecycle = event.getLifecycle();
    System.out.println("SimpleContextLifecycleListener's event " +event.getType().toString());
    if (Lifecycle.START_EVENT.equals(event.getType())) {
      System.out.println("Starting context.");
    }
    else if (Lifecycle.STOP_EVENT.equals(event.getType())) {
      System.out.println("Stopping context.");
    }
  }
}

how tomcat works 总结 二

标签：tomcat   读书笔记   valve   components   

原文地址：http://blog.csdn.net/dlf123321/article/details/40744105