@Overrideprotected void initInternal() throws LifecycleException {super.initInternal();// Initialize adapteradapter = new CoyoteAdapter(this);protocolHandler.setAdapter(adapter);// Make sure parseBodyMethodsSet has a defaultif (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 availablejsseProtocolHandler.setSslImplementationName(OpenSSLImplementation.class.getName());}}try {protocolHandler.init();} catch (Exception e) {throw new LifecycleException(sm.getString("coyoteConnector.protocolHandlerInitializationFailed"), e);}}

@Overridepublic void begin(String namespace, String name, Attributes attributes)throws Exception {Service svc = (Service)digester.peek();Executor ex = null;if ( attributes.getValue("executor")!=null ) {ex = svc.getExecutor(attributes.getValue("executor"));}Connector con = new Connector(attributes.getValue("protocol"));if (ex != null) {setExecutor(con, ex);}String sslImplementationName = attributes.getValue("sslImplementationName");if (sslImplementationName != null) {setSSLImplementationName(con, sslImplementationName);}digester.push(con);}

    <Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" /><!-- Define an AJP 1.3 Connector on port 8009 --><Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />

public Connector(String protocol) {　　　　　　//DeprcatedsetProtocol(protocol);// Instantiate protocol handlerProtocolHandler p = null;try {Class<?> clazz = Class.forName(protocolHandlerClassName);p = (ProtocolHandler) clazz.getConstructor().newInstance();} catch (Exception e) {log.error(sm.getString("coyoteConnector.protocolHandlerInstantiationFailed"), e);} finally {this.protocolHandler = p;}if (Globals.STRICT_SERVLET_COMPLIANCE) {uriCharset = StandardCharsets.ISO_8859_1;} else {uriCharset = StandardCharsets.UTF_8;}}

    public void setProtocolHandlerClassName(String protocolHandlerClassName) {this.protocolHandlerClassName = protocolHandlerClassName;}

@Overrideprotected void startInternal() throws LifecycleException {// Validate settings before startingif (getPort() < 0) {throw new LifecycleException(sm.getString("coyoteConnector.invalidPort", Integer.valueOf(getPort())));}setState(LifecycleState.STARTING);try {protocolHandler.start();} catch (Exception e) {throw new LifecycleException(sm.getString("coyoteConnector.protocolHandlerStartFailed"), e);}}

@Overridepublic void init() throws Exception {if (getLog().isInfoEnabled()) {getLog().info(sm.getString("abstractProtocolHandler.init", getName()));}if (oname == null) {// Component not pre-registered so register itoname = createObjectName();if (oname != null) {Registry.getRegistry(null, null).registerComponent(this, oname, null);}}if (this.domain != null) {rgOname = new ObjectName(domain + ":type=GlobalRequestProcessor,name=" + getName());Registry.getRegistry(null, null).registerComponent(getHandler().getGlobal(), rgOname, null);}String endpointName = getName();endpoint.setName(endpointName.substring(1, endpointName.length()-1));endpoint.setDomain(domain);endpoint.init();}

public AbstractProtocol(AbstractEndpoint<S> endpoint) {　　　　　　this.endpoint = endpoint;//Deprecated　　　　　　setSoLinger(Constants.DEFAULT_CONNECTION_LINGER);setTcpNoDelay(Constants.DEFAULT_TCP_NO_DELAY);}

public void init() throws Exception {if (bindOnInit) {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);}}}

@Overridepublic void start() throws Exception {if (getLog().isInfoEnabled()) {getLog().info(sm.getString("abstractProtocolHandler.start", getName()));}endpoint.start();// Start async timeout threadasyncTimeout = 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();}

//AbstractEndpoint.java
public final void start() throws Exception {if (bindState == BindState.UNBOUND) {bind();bindState = BindState.BOUND_ON_START;}startInternal();//要调用子类NioEndpoint.java类的实现方法
    }//NioEndpoint.java
代码如下：
@Overridepublic void startInternal() throws Exception {if (!running) {running = true;paused = false;processorCache = new SynchronizedStack<>(SynchronizedStack.DEFAULT_SIZE,socketProperties.getProcessorCache());eventCache = new SynchronizedStack<>(SynchronizedStack.DEFAULT_SIZE,socketProperties.getEventCache());nioChannels = new SynchronizedStack<>(SynchronizedStack.DEFAULT_SIZE,socketProperties.getBufferPool());// Create worker collectionif ( getExecutor() == null ) {createExecutor();}initializeConnectionLatch();// Start poller threadspollers = 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();}}

public void createExecutor() {internalExecutor = true;TaskQueue taskqueue = new TaskQueue();TaskThreadFactory tf = new TaskThreadFactory(getName() + "-exec-", daemon, getThreadPriority());executor = new ThreadPoolExecutor(getMinSpareThreads(), getMaxThreads(), 60, TimeUnit.SECONDS,taskqueue, tf);taskqueue.setParent( (ThreadPoolExecutor) executor);}

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();}}

public abstract static class Acceptor implements Runnable {public enum AcceptorState {NEW, RUNNING, PAUSED, ENDED}protected volatile AcceptorState state = AcceptorState.NEW;public final AcceptorState getState() {return state;}private String threadName;protected final void setThreadName(final String threadName) {this.threadName = threadName;}protected final String getThreadName() {return threadName;}}

@Overridepublic void startInternal() throws LifecycleException {setState(LifecycleState.STARTING);Engine engine = service.getContainer();if (engine == null) {return;}findDefaultHost();addListeners(engine);Container[] conHosts = engine.findChildren();for (Container conHost : conHosts) {Host host = (Host) conHost;if (!LifecycleState.NEW.equals(host.getState())) {// Registering the host will register the context and wrappers
                registerHost(host);}}}

    <Engine name="Catalina" defaultHost="localhost"><Realm className="org.apache.catalina.realm.UserDatabaseRealm"resourceName="UserDatabase"/><Host name="localhost"  appBase="webapps"unpackWARs="true" autoDeploy="true"><Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"  prefix="localhost_access_log." suffix=".txt"pattern="%h %l %u %t &quot;%r&quot; %s %b" resolveHosts="false"/></Host></Engine>

private void findDefaultHost() {Engine engine = service.getContainer();String defaultHost = engine.getDefaultHost();boolean found = false;if (defaultHost != null && defaultHost.length() >0) {Container[] containers = engine.findChildren();for (Container container : containers) {Host host = (Host) container;if (defaultHost.equalsIgnoreCase(host.getName())) {found = true;break;}String[] aliases = host.findAliases();for (String alias : aliases) {if (defaultHost.equalsIgnoreCase(alias)) {found = true;break;}}}}if(found) {mapper.setDefaultHostName(defaultHost);} else {log.warn(sm.getString("mapperListener.unknownDefaultHost",defaultHost, service));}}

public final class Mapper {private static final Log log = LogFactory.getLog(Mapper.class);private static final StringManager sm = StringManager.getManager(Mapper.class);// ----------------------------------------------------- Instance Variables/*** Array containing the virtual hosts definitions.*/// Package private to facilitate testingvolatile MappedHost[] hosts = new MappedHost[0];/*** Default host name.*/private String defaultHostName = null;private volatile MappedHost defaultHost = null;/*** Mapping from Context object to Context version to support* RequestDispatcher mappings.*/private final Map<Context, ContextVersion> contextObjectToContextVersionMap =new ConcurrentHashMap<>();

// ------------------------------------------------------- Host Inner Classprotected static final class MappedHost extends MapElement<Host> {public volatile ContextList contextList;/*** Link to the "real" MappedHost, shared by all aliases.*/private final MappedHost realHost;/*** Links to all registered aliases, for easy enumeration. This field* is available only in the "real" MappedHost. In an alias this field* is <code>null</code>.*/private final List<MappedHost> aliases;/*** Constructor used for the primary Host** @param name The name of the virtual host* @param host The host*/public MappedHost(String name, Host host) {super(name, host);realHost = this;contextList = new ContextList();aliases = new CopyOnWriteArrayList<>();}/*** Constructor used for an Alias** @param alias    The alias of the virtual host* @param realHost The host the alias points to*/public MappedHost(String alias, MappedHost realHost) {super(alias, realHost.object);this.realHost = realHost;this.contextList = realHost.contextList;this.aliases = null;}public boolean isAlias() {return realHost != this;}public MappedHost getRealHost() {return realHost;}public String getRealHostName() {return realHost.name;}public Collection<MappedHost> getAliases() {return aliases;}public void addAlias(MappedHost alias) {aliases.add(alias);}public void addAliases(Collection<? extends MappedHost> c) {aliases.addAll(c);}public void removeAlias(MappedHost alias) {aliases.remove(alias);}}// ------------------------------------------------ ContextList Inner Classprotected static final class ContextList {public final MappedContext[] contexts;public final int nesting;public ContextList() {this(new MappedContext[0], 0);}private ContextList(MappedContext[] contexts, int nesting) {this.contexts = contexts;this.nesting = nesting;}public ContextList addContext(MappedContext mappedContext,int slashCount) {MappedContext[] newContexts = new MappedContext[contexts.length + 1];if (insertMap(contexts, newContexts, mappedContext)) {return new ContextList(newContexts, Math.max(nesting,slashCount));}return null;}public ContextList removeContext(String path) {MappedContext[] newContexts = new MappedContext[contexts.length - 1];if (removeMap(contexts, newContexts, path)) {int newNesting = 0;for (MappedContext context : newContexts) {newNesting = Math.max(newNesting, slashCount(context.name));}return new ContextList(newContexts, newNesting);}return null;}}// ---------------------------------------------------- Context Inner Classprotected static final class MappedContext extends MapElement<Void> {public volatile ContextVersion[] versions;public MappedContext(String name, ContextVersion firstVersion) {super(name, null);this.versions = new ContextVersion[] { firstVersion };}}protected static final class ContextVersion extends MapElement<Context> {public final String path;public final int slashCount;public final WebResourceRoot resources;public String[] welcomeResources;public MappedWrapper defaultWrapper = null;public MappedWrapper[] exactWrappers = new MappedWrapper[0];public MappedWrapper[] wildcardWrappers = new MappedWrapper[0];public MappedWrapper[] extensionWrappers = new MappedWrapper[0];public int nesting = 0;private volatile boolean paused;public ContextVersion(String version, String path, int slashCount,Context context, WebResourceRoot resources,String[] welcomeResources) {super(version, context);this.path = path;this.slashCount = slashCount;this.resources = resources;this.welcomeResources = welcomeResources;}public boolean isPaused() {return paused;}public void markPaused() {paused = true;}}// ---------------------------------------------------- Wrapper Inner Classprotected static class MappedWrapper extends MapElement<Wrapper> {public final boolean jspWildCard;public final boolean resourceOnly;public MappedWrapper(String name, Wrapper wrapper, boolean jspWildCard,boolean resourceOnly) {super(name, wrapper);this.jspWildCard = jspWildCard;this.resourceOnly = resourceOnly;}}