可以看到，先 new 了 StandardServer，再 new 了 StandardService，可以理解为创建 Server 后具体是由 service 进行服务， 而在 service 中就是上面的配置文件里显示的，service 包含了 connector，可以是多个connector，负责接入，具体内容可以参看上一篇 而后是 Engine，Engine 的关系是一个 Service 有一个 Engine，Engine 负责处理真正的逻辑，
// Make sure parseBodyMethodsSet has a default if (null == parseBodyMethodsSet) { setParseBodyMethods(getParseBodyMethods()); }
if (protocolHandler.isAprRequired() && !AprStatus.isInstanceCreated()) { thrownewLifecycleException(sm.getString("coyoteConnector.protocolHandlerNoAprListener", getProtocolHandlerClassName())); } if (protocolHandler.isAprRequired() && !AprStatus.isAprAvailable()) { thrownewLifecycleException(sm.getString("coyoteConnector.protocolHandlerNoAprLibrary", getProtocolHandlerClassName())); } if (AprStatus.isAprAvailable() && AprStatus.getUseOpenSSL() && protocolHandler instanceof AbstractHttp11JsseProtocol) { AbstractHttp11JsseProtocol<?> jsseProtocolHandler = (AbstractHttp11JsseProtocol<?>) protocolHandler; if (jsseProtocolHandler.isSSLEnabled() && jsseProtocolHandler.getSslImplementationName() == null) { // OpenSSL is compatible with the JSSE configuration, so use it if APR is available jsseProtocolHandler.setSslImplementationName(OpenSSLImplementation.class.getName()); } }
try { // Loop until we receive a shutdown command while (!stopCalled) {
// Loop if endpoint is paused while (endpoint.isPaused() && !stopCalled) { state = AcceptorState.PAUSED; try { Thread.sleep(50); } catch (InterruptedException e) { // Ignore } }
if (stopCalled) { break; } state = AcceptorState.RUNNING;
try { //if we have reached max connections, wait endpoint.countUpOrAwaitConnection();
// Endpoint might have been paused while waiting for latch // If that is the case, don't accept new connections if (endpoint.isPaused()) { continue; }
Usocket=null; try { // Accept the next incoming connection from the server // socket socket = endpoint.serverSocketAccept(); } catch (Exception ioe) { // We didn't get a socket endpoint.countDownConnection(); if (endpoint.isRunning()) { // Introduce delay if necessary errorDelay = handleExceptionWithDelay(errorDelay); // re-throw throw ioe; } else { break; } } // Successful accept, reset the error delay errorDelay = 0;
// Configure the socket if (!stopCalled && !endpoint.isPaused()) { // setSocketOptions() will hand the socket off to // an appropriate processor if successful if (!endpoint.setSocketOptions(socket)) { endpoint.closeSocket(socket); } } else { endpoint.destroySocket(socket); } } catch (Throwable t) { ExceptionUtils.handleThrowable(t); Stringmsg= sm.getString("endpoint.accept.fail"); // APR specific. // Could push this down but not sure it is worth the trouble. if (t instanceof Error) { Errore= (Error) t; if (e.getError() == 233) { // Not an error on HP-UX so log as a warning // so it can be filtered out on that platform // See bug 50273 log.warn(msg, t); } else { log.error(msg, t); } } else { log.error(msg, t); } } } } finally { stopLatch.countDown(); } state = AcceptorState.ENDED; }
// Set socket properties // Disable blocking, polling will be used socket.configureBlocking(false); if (getUnixDomainSocketPath() == null) { socketProperties.setProperties(socket.socket()); }
socketWrapper.setReadTimeout(getConnectionTimeout()); socketWrapper.setWriteTimeout(getConnectionTimeout()); socketWrapper.setKeepAliveLeft(NioEndpoint.this.getMaxKeepAliveRequests()); poller.register(socketWrapper); returntrue; } catch (Throwable t) { ExceptionUtils.handleThrowable(t); try { log.error(sm.getString("endpoint.socketOptionsError"), t); } catch (Throwable tt) { ExceptionUtils.handleThrowable(tt); } if (socketWrapper == null) { destroySocket(socket); } } // Tell to close the socket if needed returnfalse; }
@Override publicvoidrun() { // Loop until destroy() is called while (true) {
booleanhasEvents=false;
try { if (!close) { hasEvents = events(); if (wakeupCounter.getAndSet(-1) > 0) { // If we are here, means we have other stuff to do // Do a non blocking select keyCount = selector.selectNow(); } else { keyCount = selector.select(selectorTimeout); } wakeupCounter.set(0); } if (close) { events(); timeout(0, false); try { selector.close(); } catch (IOException ioe) { log.error(sm.getString("endpoint.nio.selectorCloseFail"), ioe); } break; } // Either we timed out or we woke up, process events first if (keyCount == 0) { hasEvents = (hasEvents | events()); } } catch (Throwable x) { ExceptionUtils.handleThrowable(x); log.error(sm.getString("endpoint.nio.selectorLoopError"), x); continue; }
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()) { SelectionKeysk= iterator.next(); iterator.remove(); NioSocketWrappersocketWrapper= (NioSocketWrapper) sk.attachment(); // Attachment may be null if another thread has called // cancelledKey() if (socketWrapper != null) { processKey(sk, socketWrapper); } }
// Process timeouts timeout(keyCount,hasEvents); }
// 去获取处理器 // Determine handler for the current request. mappedHandler = getHandler(processedRequest); if (mappedHandler == null) { noHandlerFound(processedRequest, response); return; }
// Determine handler adapter for the current request. HandlerAdapterha= getHandlerAdapter(mappedHandler.getHandler());
// Process last-modified header, if supported by the handler. Stringmethod= request.getMethod(); booleanisGet= HttpMethod.GET.matches(method); if (isGet || HttpMethod.HEAD.matches(method)) { longlastModified= ha.getLastModified(request, mappedHandler.getHandler()); if (newServletWebRequest(request, response).checkNotModified(lastModified) && isGet) { return; } }
if (!mappedHandler.applyPreHandle(processedRequest, response)) { return; }
// Actually invoke the handler. mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
protected HandlerAdapter getHandlerAdapter(Object handler)throws ServletException { if (this.handlerAdapters != null) { for (HandlerAdapter adapter : this.handlerAdapters) { if (adapter.supports(handler)) { return adapter; } } } thrownewServletException("No adapter for handler [" + handler + "]: The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler"); }
springboot 的一个方便之处就是集成了 web server 进去，接着上一篇继续来看下这个 web server 的启动过程 这边是基于 springboot 的 2.2.9.RELEASE 版本，整个 springboot 体系主体就是看 org.springframework.context.support.AbstractApplicationContext#refresh 刷新方法，而启动 web server 的方法就是在其中的 onRefresh
/** * Template method which can be overridden to add context-specific refresh work. * Called on initialization of special beans, before instantiation of singletons. * <p>This implementation is empty. * @throws BeansException in case of errors * @see #refresh() */ protectedvoidonRefresh()throws BeansException { // For subclasses: do nothing by default. }
/** * Factory method called to create the {@link TomcatWebServer}. Subclasses can * override this method to return a different {@link TomcatWebServer} or apply * additional processing to the Tomcat server. * @param tomcat the Tomcat server. * @return a new {@link TomcatWebServer} instance */ protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) { returnnewTomcatWebServer(tomcat, getPort() >= 0); }
这里面就开始 new 了一个 TomcatWebServer， org.springframework.boot.web.embedded.tomcat.TomcatWebServer#TomcatWebServer(org.apache.catalina.startup.Tomcat, boolean)
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publicTomcatWebServer(Tomcat tomcat, boolean autoStart) { Assert.notNull(tomcat, "Tomcat Server must not be null"); this.tomcat = tomcat; this.autoStart = autoStart; initialize(); }
Contextcontext= findContext(); context.addLifecycleListener((event) -> { if (context.equals(event.getSource()) && Lifecycle.START_EVENT.equals(event.getType())) { // Remove service connectors so that protocol binding doesn't // happen when the service is started. removeServiceConnectors(); } });
// Start the server to trigger initialization listeners this.tomcat.start();
// We can re-throw failure exception directly in the main thread rethrowDeferredStartupExceptions();
try { ContextBindings.bindClassLoader(context, context.getNamingToken(), getClass().getClassLoader()); } catch (NamingException ex) { // Naming is not enabled. Continue }
// Unlike Jetty, all Tomcat threads are daemon threads. We create a // blocking non-daemon to stop immediate shutdown startDaemonAwaitThread(); } catch (Exception ex) { stopSilently(); destroySilently(); thrownewWebServerException("Unable to start embedded Tomcat", ex); } } } ``` 这里就是继续调用 `org.apache.catalina.startup.Tomcat#start` ```java publicvoidstart()throws LifecycleException { this.getServer(); this.server.start(); } ``` 获取server, `org.apache.catalina.startup.Tomcat#getServer` ```java public Server getServer() { if (this.server != null) { returnthis.server; } else { System.setProperty("catalina.useNaming", "false"); this.server = newStandardServer(); this.initBaseDir(); ConfigFileLoader.setSource(newCatalinaBaseConfigurationSource(newFile(this.basedir), (String)null)); this.server.setPort(-1); Serviceservice=newStandardService(); service.setName("Tomcat"); this.server.addService(service); returnthis.server; } }
