tomcat源码分析（一）初始化---Debug方式
引用网址：http://tomcat.apache.org/tomcat-6.0-doc/architecture/startup/serverStartup.txt
http://tomcat.apache.org/tomcat-6.0-doc/architecture/startup/serverStartup.pdf
Tomcat启动时序
第一步：初始化
类: org.apache.catalina.startup.Bootstrap
1 /**
2 * Initialize daemon.
3 */
4 public void init()
5 throws Exception
6 {
7
8 // Set Catalina path,home and base value is set to system.getProperties("user.dir"),把程序当前目录设置为catalina home和base的值。
9 setCatalinaHome();
10 setCatalinaBase();
11
12 initClassLoaders();
13
14 Thread.currentThread().setContextClassLoader(catalinaLoader);
15
16 SecurityClassLoad.securityClassLoad(catalinaLoader);
17
18 // Load our startup class and call its process() method
19 if (log.isDebugEnabled())
20 log.debug("Loading startup class");
21 Class startupClass =
22 catalinaLoader.loadClass
23 ("org.apache.catalina.startup.Catalina");
24 Object startupInstance = startupClass.newInstance();
25
26 // Set the shared extensions class loader
27 if (log.isDebugEnabled())
28 log.debug("Setting startup class properties");
29 String methodName = "setParentClassLoader";
30 Class paramTypes[] = new Class;
31 paramTypes = Class.forName("java.lang.ClassLoader");
32 Object paramValues[] = new Object;
33 paramValues = sharedLoader;
34 Method method =
35 startupInstance.getClass().getMethod(methodName, paramTypes);
36 method.invoke(startupInstance, paramValues);
37
38 catalinaDaemon = startupInstance;
39
40 }
工作流程如下:
a) Set up classloaders
commonLoader (common)-> System Loader
sharedLoader (shared)-> commonLoader -> System Loader
catalinaLoader(server) -> commonLoader -> System Loader
b) Load startup class (reflection)
org.apache.catalina.startup.Catalina
setParentClassloader -> sharedLoader
Thread.contextClassloader -> catalinaLoader
c) Bootstrap.daemon.init() complete
第二步： 处理命令行参数 (start, startd, stop, stopd)
类: org.apache.catalina.startup.Bootstrap (假定命令为start)
try {
String command = "start";
if (args.length > 0) {
command = args;
}
if (command.equals("startd")) {
args = "start";
daemon.load(args);
daemon.start();
} else if (command.equals("stopd")) {
args = "stop";
daemon.stop();
} else if (command.equals("start")) {
daemon.setAwait(true);
daemon.load(args);
daemon.start();
} else if (command.equals("stop")) {
daemon.stopServer(args);
} else {
log.warn("Bootstrap: command \"" + command + "\" does not exist.");
}
} catch (Throwable t) {
t.printStackTrace();
}
工作流程如下:
a) Catalina.setAwait(true);
b) Catalina.load()
1 public void load() {
2
3 long t1 = System.nanoTime();
4
5 initDirs();
6
7 // Before digester - it may be needed
8
9 initNaming();
10
11 // Create and execute our Digester
12 Digester digester = createStartDigester();
13
14 InputSource inputSource = null;
15 InputStream inputStream = null;
16 File file = null;
17 try {
18 file = configFile();
19 inputStream = new FileInputStream(file);
20 inputSource = new InputSource("file://" + file.getAbsolutePath());
21 } catch (Exception e) {
22 ;
23 }
24 if (inputStream == null) {
25 try {
26 inputStream = getClass().getClassLoader()
27 .getResourceAsStream(getConfigFile());
28 inputSource = new InputSource
29 (getClass().getClassLoader()
30 .getResource(getConfigFile()).toString());
31 } catch (Exception e) {
32 ;
33 }
34 }
35
36 // This should be included in catalina.jar
37 // Alternative: don't bother with xml, just create it manually.
38 if( inputStream==null ) {
39 try {
40 inputStream = getClass().getClassLoader()
41 .getResourceAsStream("server-embed.xml");
42 inputSource = new InputSource
43 (getClass().getClassLoader()
44 .getResource("server-embed.xml").toString());
45 } catch (Exception e) {
46 ;
47 }
48 }
49
50
51 if ((inputStream == null) && (file != null)) {
52 log.warn("Can't load server.xml from " + file.getAbsolutePath());
53 return;
54 }
55
56 try {
57 inputSource.setByteStream(inputStream);
58 digester.push(this);
59 digester.parse(inputSource);
60 inputStream.close();
61 } catch (Exception e) {
62 log.warn("Catalina.start using "
63 + getConfigFile() + ": " , e);
64 return;
65 }
66
67 // Stream redirection
68 initStreams();
69
70 // Start the new server
71 if (server instanceof Lifecycle) {
72 try {
73 server.initialize();
74 } catch (LifecycleException e) {
75 log.error("Catalina.start", e);
76 }
77 }
78
79 long t2 = System.nanoTime();
80 if(log.isInfoEnabled())
81 log.info("Initialization processed in " + ((t2 - t1) / 1000000) + " ms");
82
83 }
standardServer.java
1 public void initialize()
2 throws LifecycleException
3 {
4 if (initialized) {
5 log.info(sm.getString("standardServer.initialize.initialized"));
6 return;
7 }
8 lifecycle.fireLifecycleEvent(INIT_EVENT, null);
9 initialized = true;
10
11 if( oname==null ) {
12 try {
13 oname=new ObjectName( "Catalina:type=Server");
14 Registry.getRegistry(null, null)
15 .registerComponent(this, oname, null );
16 } catch (Exception e) {
17 log.error("Error registering ",e);
18 }
19 }
20
21 // Register global String cache
22 try {
23 ObjectName oname2 =
24 new ObjectName(oname.getDomain() + ":type=StringCache");
25 Registry.getRegistry(null, null)
26 .registerComponent(new StringCache(), oname2, null );
27 } catch (Exception e) {
28 log.error("Error registering ",e);
29 }
30
31 // Initialize our defined Services
32 for (int i = 0; i < services.length; i++) {
33 services.initialize();
34 }
35 }
standardService.java
public void initialize()
throws LifecycleException
{
// Service shouldn't be used with embeded, so it doesn't matter
if (initialized) {
if(log.isInfoEnabled())
log.info(sm.getString("standardService.initialize.initialized"));
return;
}
initialized = true;
if( oname==null ) {
try {
// Hack - Server should be deprecated...
Container engine=this.getContainer();
domain=engine.getName();
oname=new ObjectName(domain + ":type=Service,serviceName="+name);
this.controller=oname;
Registry.getRegistry(null, null)
.registerComponent(this, oname, null);
Executor[] executors = findExecutors();
for (int i = 0; i < executors.length; i++) {
ObjectName executorObjectName =
new ObjectName(domain + ":type=Executor,name=" + executors.getName());
Registry.getRegistry(null, null)
.registerComponent(executors, executorObjectName, null);
}
} catch (Exception e) {
log.error(sm.getString("standardService.register.failed",domain),e);
}
}
if( server==null ) {
// Register with the server
// HACK: ServerFactory should be removed...
ServerFactory.getServer().addService(this);
}
// Initialize our defined Connectors
synchronized (connectors) {
for (int i = 0; i < connectors.length; i++) {
connectors.initialize();
}
}
}
connector.java
1 public void initialize()
2 throws LifecycleException
3 {
4 if (initialized) {
5 if(log.isInfoEnabled())
6 log.info(sm.getString("coyoteConnector.alreadyInitialized"));
7 return;
8 }
9
10 this.initialized = true;
11
12 if( oname == null && (container instanceof StandardEngine)) {
13 try {
14 // we are loaded directly, via API - and no name was given to us
15 StandardEngine cb=(StandardEngine)container;
16 oname = createObjectName(cb.getName(), "Connector");
17 Registry.getRegistry(null, null)
18 .registerComponent(this, oname, null);
19 controller=oname;
20 } catch (Exception e) {
21 log.error( "Error registering connector ", e);
22 }
23 if(log.isDebugEnabled())
24 log.debug("Creating name for connector " + oname);
25 }
26
27 // Initializa adapter
28 adapter = new CoyoteAdapter(this);
29 protocolHandler.setAdapter(adapter);
30
31 IntrospectionUtils.setProperty(protocolHandler, "jkHome",
32 System.getProperty("catalina.base"));
33
34 try {
35 protocolHandler.init();
36 } catch (Exception e) {
37 throw new LifecycleException
38 (sm.getString
39 ("coyoteConnector.protocolHandlerInitializationFailed", e));
40 }
41 }
Http11Protocol.java初始化
1 public void init() throws Exception {
2 endpoint.setName(getName());
3 endpoint.setHandler(cHandler);
4
5 // Verify the validity of the configured socket factory
6 try {
7 if (isSSLEnabled()) {
8 sslImplementation =
9 SSLImplementation.getInstance(sslImplementationName);
10 socketFactory = sslImplementation.getServerSocketFactory();
11 endpoint.setServerSocketFactory(socketFactory);
12 } else if (socketFactoryName != null) {
13 socketFactory = (ServerSocketFactory) Class.forName(socketFactoryName).newInstance();
14 endpoint.setServerSocketFactory(socketFactory);
15 }
16 } catch (Exception ex) {
17 log.error(sm.getString("http11protocol.socketfactory.initerror"),
18 ex);
19 throw ex;
20 }
21
22 if (socketFactory!=null) {
23 Iterator<String> attE = attributes.keySet().iterator();
24 while( attE.hasNext() ) {
25 String key = attE.next();
26 Object v=attributes.get(key);
27 socketFactory.setAttribute(key, v);
28 }
29 }
30
31 try {
32 endpoint.init();
33 } catch (Exception ex) {
34 log.error(sm.getString("http11protocol.endpoint.initerror"), ex);
35 throw ex;
36 }
37 if (log.isInfoEnabled())
38 log.info(sm.getString("http11protocol.init", getName()));
39
40 }
JIoEndpoint.java
* Handle incoming TCP connections.
*
* This class implement a simple server model: one listener thread accepts on a socket and
* creates a new worker thread for each incoming connection.
*
* More advanced Endpoints will reuse the threads, use queues, etc.
1 public void init()
2 throws Exception {
3
4 if (initialized)
5 return;
6
7 // Initialize thread count defaults for acceptor
8 if (acceptorThreadCount == 0) {
9 acceptorThreadCount = 1;
10 }
11 if (serverSocketFactory == null) {
12 serverSocketFactory = ServerSocketFactory.getDefault();
13 }
14 if (serverSocket == null) {
15 try {
16 if (address == null) {
17 serverSocket = serverSocketFactory.createSocket(port, backlog);
18 } else {
19 serverSocket = serverSocketFactory.createSocket(port, backlog, address);
20 }
21 } catch (BindException be) {
22 if (address == null)
23 throw new BindException(be.getMessage() + "<null>:" + port);
24 else
25 throw new BindException(be.getMessage() + " " +
26 address.toString() + ":" + port);
27 }
28 }
29 //if( serverTimeout >= 0 )
30 // serverSocket.setSoTimeout( serverTimeout );
31
32 initialized = true;
33
34 }
b1) initDirs() -> set properties like
catalina.home
catalina.base == catalina.home (most cases)
b2) initNaming
setProperty(javax.naming.Context.INITIAL_CONTEXT_FACTORY,
org.apache.naming.java.javaURLContextFactory ->default)
b3) createStartDigester()
Configures a digester for the main server.xml elements like
org.apache.catalina.core.StandardServer (can change of course :)
org.apache.catalina.deploy.NamingResources
Stores naming resources in the J2EE JNDI tree
org.apache.catalina.LifecycleListener
implements events for start/stop of major components
org.apache.catalina.core.StandardService
The single entry for a set of connectors,
so that a container can listen to multiple connectors
ie, single entry
org.apache.coyote.tomcat5.CoyoteConnector
Connectors to listen for incoming requests only
It also adds the following rulesets to the digester
NamingRuleSet
EngineRuleSet
HostRuleSet
ContextRuleSet
b4) Load the server.xml and parse it using the digester
Parsing the server.xml using the digester is an automatic
XML-object mapping tool, that will create the objects defined in server.xml
Startup of the actual container has not started yet.
b5) Assigns System.out and System.err to the SystemLogHandler class
b6) Calls initialize on all components, this makes each object register itself with the
JMX agent.
During the process call the Connectors also initialize the adapters.
The adapters are the components that do the request pre-processing.
Typical adapters are HTTP1.1 (default if no protocol is specified,
org.apache.coyote.http11.Http11Protocol)
AJP1.3 for mod_jk etc.
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