SpringApplication的启动，run方法返回一个ConfigurableApplicationContext。
public static void main(String[] args) {
SpringApplication.run(OutsideServiceApplication.class, args);
}最后调用SrpingApplication的方法：
StopWatch stopWatch = new StopWatch();
stopWatch.start();
ConfigurableApplicationContext context = null;
Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
configureHeadlessProperty();
SpringApplicationRunListeners listeners = getRunListeners(args);
listeners.starting();
try {
ApplicationArguments applicationArguments = new DefaultApplicationArguments(
args);
这里准备环境（环境变量等）spring有提供接口可扩展
ConfigurableEnvironment environment = prepareEnvironment(listeners,
applicationArguments);
configureIgnoreBeanInfo(environment);
Banner printedBanner = printBanner(environment);
// 这里创建上下文 ConfigurableApplicationContext ，这里创建会根据应用类型创建不同的上下文，这里是servlet应用所以创建的 AnnotationConfigServletWebServerApplicationContext
context = createApplicationContext();
exceptionReporters = getSpringFactoriesInstances(
SpringBootExceptionReporter.class,
new Class[] { ConfigurableApplicationContext.class }, context);
prepareContext(context, environment, listeners, applicationArguments,
printedBanner);
refreshContext(context);
afterRefresh(context, applicationArguments);
stopWatch.stop();
if (this.logStartupInfo) {
new StartupInfoLogger(this.mainApplicationClass)
.logStarted(getApplicationLog(), stopWatch);
}
listeners.started(context);
callRunners(context, applicationArguments);
}refreshContext(context); 最后org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext#refresh --> super.refresh() 即org.springframework.context.support.AbstractApplicationContext#refresh
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// Prepare this context for refreshing.
prepareRefresh();
// Tell the subclass to refresh the internal bean factory.
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
postProcessBeanFactory(beanFactory);
// Invoke factory processors registered as beans in the context.
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
initMessageSource();
// Initialize event multicaster for this context.
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
重点是这里会启动tomcat
onRefresh();
// Check for listener beans and register them.
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
finishRefresh();
}onRefresh（） 是由子类实现的
org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext#onRefresh
protected void onRefresh() {
super.onRefresh();
try {
createWebServer();
}
catch (Throwable ex) {
throw new ApplicationContextException("Unable to start web server", ex);
}
}
private void createWebServer() {
WebServer webServer = this.webServer;
ServletContext servletContext = getServletContext();
if (webServer == null && servletContext == null) {
会在上下文中获取factory{return getBeanFactory().getBean(beanNames[0], ServletWebServerFactory.class);}
ServletWebServerFactory factory = getWebServerFactory();
this.webServer = factory.getWebServer(getSelfInitializer());
}
else if (servletContext != null) {
try {
getSelfInitializer().onStartup(servletContext);
}
catch (ServletException ex) {
throw new ApplicationContextException("Cannot initialize servlet context",
ex);
}
}
initPropertySources();
}
获取webServer。org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory#getWebServer
@Override
public WebServer getWebServer(ServletContextInitializer... initializers) {
Tomcat tomcat = new Tomcat();
File baseDir = (this.baseDirectory != null) ? this.baseDirectory
: createTempDir("tomcat");
路径 C:\Users\lixiaojian\AppData\Local\Temp\tomcat.5770190770538359477.9099
tomcat.setBaseDir(baseDir.getAbsolutePath());
Connector connector = new Connector(this.protocol);
tomcat.getService().addConnector(connector);
customizeConnector(connector);
tomcat.setConnector(connector);
tomcat.getHost().setAutoDeploy(false);
configureEngine(tomcat.getEngine());
for (Connector additionalConnector : this.additionalTomcatConnectors) {
tomcat.getService().addConnector(additionalConnector);
}
prepareContext(tomcat.getHost(), initializers);
return getTomcatWebServer(tomcat);
}一个tomcat对应一个service，service 添加 connector，tomcat 在配置Engine。connector 构造器传入protocal。默认是
org.apache.coyote.http11.Http11NioProtocol ， 就是一个proprocolHandle
org.springframework.boot.web.embedded.tomcat.TomcatWebServer#TomcatWebServer(org.apache.catalina.startup.Tomcat, boolean)
public TomcatWebServer(Tomcat tomcat, boolean autoStart) {
Assert.notNull(tomcat, "Tomcat Server must not be null");
this.tomcat = tomcat;
this.autoStart = autoStart;
initialize();
}
private void initialize() throws WebServerException {
TomcatWebServer.logger
.info("Tomcat initialized with port(s): " + getPortsDescription(false));
synchronized (this.monitor) {
try {
addInstanceIdToEngineName();
Context context = 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();
throw new WebServerException("Unable to start embedded Tomcat", ex);
}
}
}org.apache.catalina.startup.Tomcat#start 核心代码tomcat启动
public void start() throws LifecycleException {
getServer();
getConnector();
server.start();
}
创建 server：
public Server getServer() {
// start 调用方法时候，server都是前面已经创建完成了的
if (server != null) {
return server;
}
System.setProperty("catalina.useNaming", "false");
server = new StandardServer();
initBaseDir();
server.setPort( -1 );
Service service = new StandardService();
service.setName("Tomcat");
server.addService(service);
return server;
}
public Connector getConnector() {
Service service = getService();
if (service.findConnectors().length > 0) {
前面已经创建好了的
return service.findConnectors()[0];
}
if (defaultConnectorCreated) {
return null;
}
// The same as in standard Tomcat configuration.
// This creates an APR HTTP connector if AprLifecycleListener has been
// configured (created) and Tomcat Native library is available.
// Otherwise it creates a NIO HTTP connector.
Connector connector = new Connector("HTTP/1.1");
connector.setPort(port);
service.addConnector(connector);
defaultConnectorCreated = true;
return connector;
}
public Server getServer() {
if (server != null) {
return server;
}
System.setProperty("catalina.useNaming", "false");
// tomcat 会创建一个server
server = new StandardServer();
initBaseDir();
server.setPort( -1 );
Service service = new StandardService();
service.setName("Tomcat");
server.addService(service);
return server;
}
org.apache.catalina.util.LifecycleBase#start
if (state.equals(LifecycleState.NEW)) {
init();
}
public final synchronized void init() throws LifecycleException {
if (!state.equals(LifecycleState.NEW)) {
invalidTransition(Lifecycle.BEFORE_INIT_EVENT);
}
try {
setStateInternal(LifecycleState.INITIALIZING, null, false);
initInternal();
setStateInternal(LifecycleState.INITIALIZED, null, false);
}
}org.apache.catalina.core.StandardServer#initInternal
initInternal这里实现类太多了，我们关注重点组件Connector，进入initInternal方法，来到了Connector类的initInternal()
@Override
protected void initInternal() throws LifecycleException {
super.initInternal();
// Initialize adapter
adapter = new CoyoteAdapter(this);
protocolHandler.setAdapter(adapter);
// Make sure parseBodyMethodsSet has a default
if (null == parseBodyMethodsSet) {
setParseBodyMethods(getParseBodyMethods());
}
if (protocolHandler.isAprRequired() && !AprLifecycleListener.isAprAvailable()) {
throw new LifecycleException(sm.getString("coyoteConnector.protocolHandlerNoApr",
getProtocolHandlerClassName()));
}
if (AprLifecycleListener.isAprAvailable() && AprLifecycleListener.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 {
protocolHandler.init();
} catch (Exception e) {
throw new LifecycleException(
sm.getString("coyoteConnector.protocolHandlerInitializationFailed"), e);
}
}protocolHandler.init();
org.apache.coyote.http11.AbstractHttp11Protocol#init 调用supper
org.apache.coyote.AbstractProtocol#init
init(){
String endpointName = getName();
endpoint.setName(endpointName.substring(1, endpointName.length()-1));
endpoint.setDomain(domain);
endpoint.init();
}org.apache.tomcat.util.net.AbstractJsseEndpoint#init 调用supper
org.apache.tomcat.util.net.AbstractEndpoint#init
public void init() throws Exception {
if (bindOnInit) {
核心代码
bind();
bindState = BindState.BOUND_ON_INIT;
}
if (this.domain != null) {
// Register endpoint (as ThreadPool - historical name)
oname = new ObjectName(domain + ":type=ThreadPool,name=\"" + getName() + "\"");
Registry.getRegistry(null, null).registerComponent(this, oname, null);
for (SSLHostConfig sslHostConfig : findSslHostConfigs()) {
registerJmx(sslHostConfig);
}
}
}org.apache.tomcat.util.net.NioEndpoint#bind 最终启动socket
public void bind() throws Exception {
serverSock = ServerSocketChannel.open();
socketProperties.setProperties(serverSock.socket());
InetSocketAddress addr = (getAddress()!=null?new InetSocketAddress(getAddress(),getPort()):new InetSocketAddress(getPort()));
serverSock.socket().bind(addr,getAcceptCount());
serverSock.configureBlocking(true); //mimic APR behavior
// Initialize thread count defaults for acceptor, poller
if (acceptorThreadCount == 0) {
// FIXME: Doesn't seem to work that well with multiple accept threads
acceptorThreadCount = 1;
}
if (pollerThreadCount <= 0) {
//minimum one poller thread
pollerThreadCount = 1;
}
setStopLatch(new CountDownLatch(pollerThreadCount));
// Initialize SSL if needed
initialiseSsl();
selectorPool.open();
}
tomcat-start --》 server.start --》
init(); 前面介绍的，最终完成socket连接
startInternal();
stop();
startInternal 同样重点介绍connector的此方法
@Override
protected void startInternal() throws LifecycleException {
setState(LifecycleState.STARTING);
try {
核心代码
protocolHandler.start();
} catch (Exception e) {
throw new LifecycleException(
sm.getString("coyoteConnector.protocolHandlerStartFailed"), e);
}
}org.apache.coyote.AbstractProtocol#start
@Override
public void start() throws Exception {
if (getLog().isInfoEnabled()) {
getLog().info(sm.getString("abstractProtocolHandler.start", getName()));
}
endpoint.start();
// Start async timeout thread
asyncTimeout = new AsyncTimeout();
Thread timeoutThread = new Thread(asyncTimeout, getNameInternal() + "-AsyncTimeout");
int priority = endpoint.getThreadPriority();
if (priority < Thread.MIN_PRIORITY || priority > Thread.MAX_PRIORITY) {
priority = Thread.NORM_PRIORITY;
}
timeoutThread.setPriority(priority);
timeoutThread.setDaemon(true);
timeoutThread.start();
}org.apache.tomcat.util.net.AbstractEndpoint#start 调org.apache.tomcat.util.net.NioEndpoint#startInternal
// Start poller threads
pollers = new Poller[getPollerThreadCount()];
for (int i=0; i<pollers.length; i++) {
pollers[i] = new Poller();
Thread pollerThread = new Thread(pollers[i], getName() + "-ClientPoller-"+i);
pollerThread.setPriority(threadPriority);
pollerThread.setDaemon(true);
pollerThread.start();
}
startAcceptorThreads();Acceptor 实现runable方法，接受创建一个socket。
protected final void startAcceptorThreads() {
int count = getAcceptorThreadCount();
acceptors = new Acceptor[count];
for (int i = 0; i < count; i++) {
acceptors[i] = createAcceptor();
String threadName = getName() + "-Acceptor-" + i;
acceptors[i].setThreadName(threadName);
Thread t = new Thread(acceptors[i], threadName);
t.setPriority(getAcceptorThreadPriority());
t.setDaemon(getDaemon());
t.start();
}
}
protected class Acceptor extends AbstractEndpoint.Acceptor {
@Override
public void run() {
while (running) {
try {
SocketChannel socket = null;
try {
// Accept the next incoming connection from the server
// socket
socket = serverSock.accept();
} catch (IOException ioe) {
// We didn't get a socket
countDownConnection();
if (running) {
// 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 (running && !paused) {
// setSocketOptions() will hand the socket off to
// an appropriate processor if successful
if (!setSocketOptions(socket)) {
closeSocket(socket);
}
} else {
closeSocket(socket);
}
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
log.error(sm.getString("endpoint.accept.fail"), t);
}
}
state = AcceptorState.ENDED;
}
poller 实现runable方法
public void run() {
// Loop until destroy() is called
while (true) {
//either we timed out or we woke up, process events first
if ( keyCount == 0 ) hasEvents = (hasEvents | events());
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();
核心代码
processKey(sk, attachment);
}
}//while
//process timeouts
timeout(keyCount,hasEvents);
}//while
getStopLatch().countDown();
}org.apache.tomcat.util.net.NioEndpoint.Poller#processKey 处理读写事件
processSocket(attachment, SocketEvent.OPEN_READ, true)
processSocket(attachment, SocketEvent.OPEN_WRITE, true)
org.apache.tomcat.util.net.AbstractEndpoint#processSocket
sc = createSocketProcessor(socketWrapper, event);
Executor executor = getExecutor();
executor.execute(sc);org.apache.tomcat.util.net.NioEndpoint.SocketProcessor#doRun
state = getHandler().process(socketWrapper, SocketEvent.OPEN_READ);org.apache.coyote.AbstractProtocol.ConnectionHandler#process
SocketState state = SocketState.CLOSED;
do {
state = processor.process(wrapper, status);
if (state == SocketState.UPGRADING) {org.apache.coyote.AbstractProcessorLight#process
state = service(socketWrapper);org.apache.coyote.http11.Http11Processor#service
// Flags
keepAlive = true;
openSocket = false;
readComplete = true;
getAdapter().service(request, response);org.apache.catalina.connector.CoyoteAdapter#service 最终章
这里的request 和 response 是coyote包下的
@Override
public void service(org.apache.coyote.Request req, org.apache.coyote.Response res)
throws Exception {
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);
// Set as notes
req.setNote(ADAPTER_NOTES, request);
res.setNote(ADAPTER_NOTES, response);
// Set query string encoding
req.getParameters().setQueryStringCharset(connector.getURICharset());
}
boolean async = false;
boolean postParseSuccess = false;
req.getRequestProcessor().setWorkerThreadName(THREAD_NAME.get());
try {
// Parse and set Catalina and configuration specific
// request parameters
postParseSuccess = postParseRequest(req, request, res, response);
if (postParseSuccess) {
//check valves if we support async
request.setAsyncSupported(
connector.getService().getContainer().getPipeline().isAsyncSupported());
// Calling the container
这里最终交给容器管道第一个阀门去处理，此时的request是org.apache.catalina.connector.Request，但是内部依旧是coyote的request。
connector.getService().getContainer().getPipeline().getFirst().invoke(
request, response);
}
if (request.isAsync()) {
async = true;
ReadListener readListener = req.getReadListener();
if (readListener != null && request.isFinished()) {
// Possible the all data may have been read during service()
// method so this needs to be checked here
ClassLoader oldCL = null;
try {
oldCL = request.getContext().bind(false, null);
if (req.sendAllDataReadEvent()) {
req.getReadListener().onAllDataRead();
}
} finally {
request.getContext().unbind(false, oldCL);
}
}
Throwable throwable =
(Throwable) request.getAttribute(RequestDispatcher.ERROR_EXCEPTION);
// If an async request was started, is not going to end once
// this container thread finishes and an error occurred, trigger
// the async error process
if (!request.isAsyncCompleting() && throwable != null) {
request.getAsyncContextInternal().setErrorState(throwable, true);
}
} else {
request.finishRequest();
response.finishResponse();
}
} catch (IOException e) {
// Ignore
} finally {
AtomicBoolean error = new AtomicBoolean(false);
res.action(ActionCode.IS_ERROR, error);
if (request.isAsyncCompleting() && error.get()) {
// Connection will be forcibly closed which will prevent
// completion happening at the usual point. Need to trigger
// call to onComplete() here.
res.action(ActionCode.ASYNC_POST_PROCESS, null);
async = false;
}
// Access log
if (!async && postParseSuccess) {
// Log only if processing was invoked.
// If postParseRequest() failed, it has already logged it.
Context context = request.getContext();
// If the context is null, it is likely that the endpoint was
// shutdown, this connection closed and the request recycled in
// a different thread. That thread will have updated the access
// log so it is OK not to update the access log here in that
// case.
if (context != null) {
context.logAccess(request, response,
System.currentTimeMillis() - req.getStartTime(), false);
}
}
req.getRequestProcessor().setWorkerThreadName(null);
// Recycle the wrapper request and response
if (!async) {
request.recycle();
response.recycle();
}
}
}