tomcat源码解析三

分析http请求的路径分析，之前说过socket完成对端口的监听：

先看下connector:

 public Connector(String protocol) {...
        try {
            Class<?> clazz = Class.forName(protocolHandlerClassName);//默认的protocolHandler为String protocolHandlerClassName ="org.apache.coyote.http11.Http11NioProtocol";...
startInternal（）{...
    protocolHandler.start();
...}
AbstractProtocol.start(){...
    endpoint.start();
...}

查看EndPoint,java8后使用的是NioEndpoint：查看ctrl+F12可以看到有相关的几个内部类Acceptor（接受请求）、Poller（从请求池中获取请求）、SocketProcessor（解析请求）

Acceptor.run(){...     
     socket = serverSock.accept();// Accept the next incoming connection from the server...
    if (running && !paused) {
         if (!setSocketOptions(socket)) {// setSocketOptions() will hand the socket off to an appropriate processor if successful
...}
setSocketOptions(){
    if (isSSLEnabled()) {
         channel = new SecureNioChannel(socket, bufhandler, selectorPool, this);//https
       } else {
         channel = new NioChannel(socket, bufhandler);//http1.1
       }...
    getPoller0().register(channel);
}
//Registers a newly created socket with the poller.
public void register(final NioChannel socket) {
      socket.setPoller(this);
      NioSocketWrapper ka = new NioSocketWrapper(socket, NioEndpoint.this);
      socket.setSocketWrapper(ka);
      ka.setPoller(this);
      ka.setReadTimeout(getSocketProperties().getSoTimeout());
      ka.setWriteTimeout(getSocketProperties().getSoTimeout());
      ka.setKeepAliveLeft(NioEndpoint.this.getMaxKeepAliveRequests());
      ka.setSecure(isSSLEnabled());
      ka.setReadTimeout(getConnectionTimeout());
      ka.setWriteTimeout(getConnectionTimeout());
      PollerEvent r = eventCache.pop();
      ka.interestOps(SelectionKey.OP_READ);//this is what OP_REGISTER turns into.
      if ( r==null) r = new PollerEvent(socket,ka,OP_REGISTER);
      else r.reset(socket,ka,OP_REGISTER);
      addEvent(r);//注册当前channel封装成pollerEvent进队列
}

查看Poller

run() {...
     events();//遍历pollerEvent依次调用pollerEvent的run将socket注册进selector（选择processor）中...
     Iterator<SelectionKey> iterator = keyCount > 0 ? selector.selectedKeys().iterator() : null;
        // Walk through the collection of ready keys and dispatch any active event.
        while (iterator != null && iterator.hasNext()) {
           SelectionKey sk = iterator.next();
           NioSocketWrapper attachment = (NioSocketWrapper)sk.attachment();
           // Attachment may be null if another thread has called cancelledKey()
              if (attachment == null) {
                  iterator.remove();
              } else {
                  iterator.remove();
                  processKey(sk, attachment);
...}
processKey{...
    if ( attachment.getSendfileData() != null ) {...
       processSendfile(sk,attachment, false);
        if (sk.isReadable()) {// Read goes before writec
        if (!processSocket(attachment, SocketEvent.OPEN_READ, true)) {
    ...} 
...}
processSocket{...
    sc = createSocketProcessor(socketWrapper, event);//创建socketProcessor给coyotaAdapter用 默认是Http11Processor
    Executor executor = getExecutor();
            if (dispatch && executor != null) {
                executor.execute(sc);
...}
AbstractHttp11Protocol.createProcessor(){...
        Http11Processor processor = new Http11Processor(this, getEndpoint());
        processor.setAdapter(getAdapter());//设置Adapter
        processor.setMaxKeepAliveRequests(getMaxKeepAliveRequests());
        processor.setConnectionUploadTimeout(getConnectionUploadTimeout());
        processor.setDisableUploadTimeout(getDisableUploadTimeout());
        processor.setRestrictedUserAgents(getRestrictedUserAgents());
        processor.setMaxSavePostSize(getMaxSavePostSize());
        return processor;
...}

查看CoyoteAdapter

service{...
        Request request = (Request) req.getNote(ADAPTER_NOTES);
        Response response = (Response) res.getNote(ADAPTER_NOTES);
        if (request == null) {
            // Create objects
            request = connector.createRequest();
            request.setCoyoteRequest(req);
            response = connector.createResponse();
            response.setCoyoteResponse(res);

            // Link objects
            request.setResponse(response);
            response.setRequest(request);...
         try {
            // Parse and set Catalina and configuration specific request parameters
            postParseSuccess = postParseRequest(req, request, res, response);//在map中解析业务请求
            if (postParseSuccess) {
                //check valves if we support async
                request.setAsyncSupported(
                        connector.getService().getContainer().getPipeline().isAsyncSupported());
                // Calling the container
                connector.getService().getContainer().getPipeline().getFirst().invoke(
                        request, response);//开始转向Cotainer Engine 每个容器有一个管道如@1，维护Valve(connector.getService().getContainer().getPipeline().getFirst())
            }
...}
@1
StandardEngine.startInternal{...
    // Start the Valves in our pipeline (including the basic), if any
        if (pipeline instanceof Lifecycle) {
            ((Lifecycle) pipeline).start();
        }
...}

查看StandardEngineValve:

//责任链模式
invoke(){...
    // Select the Host to be used for this Request
    Host host = request.getHost();...
    // Ask this Host to process this request
        host.getPipeline().getFirst().invoke(request, response);
...}

查看StandardHostValve:

invoke(Request request, Response response){...
    // Select the Context to be used for this Request
    Context context = request.getContext();
    if (context == null) {
        return;
    }
    if (request.isAsyncSupported()) {
        request.setAsyncSupported(context.getPipeline().isAsyncSupported());
    }
...}

查看StandardWrapperValve:

invoke(Request request, Response response){...
        // Allocate a servlet instance to process this request
        try {
            if (!unavailable) {
                servlet = wrapper.allocate();//实例化servlet
            }...
        MessageBytes requestPathMB = request.getRequestPathMB();
        DispatcherType dispatcherType = DispatcherType.REQUEST;
        if (request.getDispatcherType()==DispatcherType.ASYNC) dispatcherType = DispatcherType.ASYNC;
        request.setAttribute(Globals.DISPATCHER_TYPE_ATTR,dispatcherType);
        request.setAttribute(Globals.DISPATCHER_REQUEST_PATH_ATTR,
                requestPathMB);
        // Create the filter chain for this request
        ApplicationFilterChain filterChain =
                ApplicationFilterFactory.createFilterChain(request, wrapper, servlet);//创建过滤链...
        filterChain.doFilter(request.getRequest(), response.getResponse());//执行过滤链
        finally {
            // Release the filter chain (if any) for this request
            if (filterChain != null) {
                filterChain.release();
            }
            // Deallocate the allocated servlet instance
            try {
                if (servlet != null) {
                    wrapper.deallocate(servlet);
                }
...}