tomcat源码阅读_代码篇1

首先读Bootstrap类，该类在how Tomcat works里有比较详细的介绍，结合书和代码看应该没有问题。接下来看Catalina类，主要主要该类中的start()方法：

/**

* Start a new server instance.

*/

public void start() {

if (server == null) {

load();

}

long t1 = System.nanoTime();

// Start the new server

if (server instanceof Lifecycle) {

try {

((Lifecycle) server).start();

} catch (LifecycleException e) {

log.error("Catalina.start: ", e);

}

}

long t2 = System.nanoTime();

if(log.isInfoEnabled())

log.info("Server startup in " + ((t2 - t1) / 1000000) + " ms");

try {

// Register shutdown hook

if (useShutdownHook) {

if (shutdownHook == null) {

shutdownHook = new CatalinaShutdownHook();

}

Runtime.getRuntime().addShutdownHook(shutdownHook);

}

} catch (Throwable t) {

// This will fail on JDK 1.2. Ignoring, as Tomcat can run

// fine without the shutdown hook.

}

if (await) {

await();

stop();

}

}

下面是使用的时候的load方法

/**

* Start a new server instance.

*/

public void load() {

long t1 = System.nanoTime();

initDirs();

// Before digester - it may be needed

initNaming();

// Create and execute our Digester初始化组件根据XML文件在这里完成

Digester digester = createStartDigester();

InputSource inputSource = null;

InputStream inputStream = null;

File file = null;

try {

file = configFile();

inputStream = new FileInputStream(file);

inputSource = new InputSource("file://" + file.getAbsolutePath());

} catch (Exception e) {

;

}

if (inputStream == null) {

try {

inputStream = getClass().getClassLoader()

.getResourceAsStream(getConfigFile());

inputSource = new InputSource

(getClass().getClassLoader()

.getResource(getConfigFile()).toString());

} catch (Exception e) {

;

}

}

// This should be included in catalina.jar

// Alternative: don't bother with xml, just create it manually.

if( inputStream==null ) {

try {

inputStream = getClass().getClassLoader()

.getResourceAsStream("server-embed.xml");

inputSource = new InputSource

(getClass().getClassLoader()

.getResource("server-embed.xml").toString());

} catch (Exception e) {

;

}

}

if ((inputStream == null) && (file != null)) {

log.warn("Can't load server.xml from " + file.getAbsolutePath());

return;

}

try {

inputSource.setByteStream(inputStream);

digester.push(this);

digester.parse(inputSource);

inputStream.close();

} catch (Exception e) {

log.warn("Catalina.start using "

+ getConfigFile() + ": " , e);

return;

}

// Stream redirection

initStreams();

// Start the new server

if (server instanceof Lifecycle) {

try {

server.initialize();

} catch (LifecycleException e) {

log.error("Catalina.start", e);

}

}

long t2 = System.nanoTime();

if(log.isInfoEnabled())

log.info("Initialization processed in " + ((t2 - t1) / 1000000) + " ms");

}