百木园目录
- 静态代码块
- main()方法
- init()方法
- initClassLoaders()方法
- load()方法
- start()方法
上一章，我们下载源码，并启动了源码，Tomcat源码分析（一）启动Tomcat源码 。
现在，我们来看看Bootstrap启动类做了些什么工作。
静态代码块
设置了catelina.home和catalina.base
点击查看代码
static {
// Will always be non-null
// 当前工作目录的路径，总是不会为null
String userDir = System.getProperty(\"user.dir\");
// Home first
String home = System.getProperty(Constants.CATALINA_HOME_PROP);
File homeFile = null;
if (home != null) {
File f = new File(home);
try {
homeFile = f.getCanonicalFile();
} catch (IOException ioe) {
homeFile = f.getAbsoluteFile();
}
}
if (homeFile == null) {
// First fall-back. See if current directory is a bin directory
// in a normal Tomcat install
File bootstrapJar = new File(userDir, \"bootstrap.jar\");
if (bootstrapJar.exists()) {
File f = new File(userDir, \"..\");
try {
homeFile = f.getCanonicalFile();
} catch (IOException ioe) {
homeFile = f.getAbsoluteFile();
}
}
}
if (homeFile == null) {
// Second fall-back. Use current directory
File f = new File(userDir);
try {
homeFile = f.getCanonicalFile();
} catch (IOException ioe) {
homeFile = f.getAbsoluteFile();
}
}
catalinaHomeFile = homeFile;
// 设置了catelina.home
System.setProperty(Constants.CATALINA_HOME_PROP, catalinaHomeFile.getPath());
// Then base
String base = System.getProperty(Constants.CATALINA_BASE_PROP);
if (base == null) {
catalinaBaseFile = catalinaHomeFile;
} else {
File baseFile = new File(base);
try {
baseFile = baseFile.getCanonicalFile();
} catch (IOException ioe) {
baseFile = baseFile.getAbsoluteFile();
}
catalinaBaseFile = baseFile;
}
// 设置了catalina.base
System.setProperty(Constants.CATALINA_BASE_PROP, catalinaBaseFile.getPath());
}
main()方法
1.加锁新建一个Bootstrap对象，调用init初始化并且赋值给了私有静态对象daemon
2.调用了daemon对象load和start方法，而load和start方法里面利用了反射调用了catalinaDeamon的load和start方法
点击查看代码
/**
* Main method and entry point when starting Tomcat via the provided
* scripts.
*
* @param args Command line arguments to be processed
*/
public static void main(String args[]) {
synchronized (daemonLock) {
if (daemon == null) {
// Don\'t set daemon until init() has completed
Bootstrap bootstrap = new Bootstrap();
try {
bootstrap.init();
} catch (Throwable t) {
handleThrowable(t);
t.printStackTrace();
return;
}
daemon = bootstrap;
} else {
// When running as a service the call to stop will be on a new
// thread so make sure the correct class loader is used to
// prevent a range of class not found exceptions.
Thread.currentThread().setContextClassLoader(daemon.catalinaLoader);
}
}
try {
String command = \"start\";
if (args.length > 0) {
command = args[args.length - 1];
}
if (command.equals(\"startd\")) {
args[args.length - 1] = \"start\";
daemon.load(args);
daemon.start();
} else if (command.equals(\"stopd\")) {
args[args.length - 1] = \"stop\";
daemon.stop();
} else if (command.equals(\"start\")) {
daemon.setAwait(true);
daemon.load(args);
daemon.start();
if (null == daemon.getServer()) {
System.exit(1);
}
} else if (command.equals(\"stop\")) {
daemon.stopServer(args);
} else if (command.equals(\"configtest\")) {
daemon.load(args);
if (null == daemon.getServer()) {
System.exit(1);
}
System.exit(0);
} else {
log.warn(\"Bootstrap: command \\\"\" + command + \"\\\" does not exist.\");
}
} catch (Throwable t) {
// Unwrap the Exception for clearer error reporting
if (t instanceof InvocationTargetException &&
t.getCause() != null) {
t = t.getCause();
}
handleThrowable(t);
t.printStackTrace();
System.exit(1);
}
}
init()方法
1.使用initClassLoaders()创建了commonLoader、catalinaLoader和sharedLoader
2.利用反射新建一个org.apache.catalina.startup.Catalina类对象，赋值给了catalinaDeamon。
点击查看代码
/**
* Initialize daemon.
* @throws Exception Fatal initialization error
*/
public void init() throws Exception {
initClassLoaders();
Thread.currentThread().setContextClassLoader(catalinaLoader);
SecurityClassLoad.securityClassLoad(catalinaLoader);
// Load our startup class and call its process() method
// 加载启动类并调用其process（）方法
if (log.isDebugEnabled()) {
log.debug(\"Loading startup class\");
}
Class<?> startupClass = catalinaLoader.loadClass(\"org.apache.catalina.startup.Catalina\");
Object startupInstance = startupClass.getConstructor().newInstance();
// Set the shared extensions class loader
if (log.isDebugEnabled()) {
log.debug(\"Setting startup class properties\");
}
String methodName = \"setParentClassLoader\";
Class<?> paramTypes[] = new Class[1];
paramTypes[0] = Class.forName(\"java.lang.ClassLoader\");
Object paramValues[] = new Object[1];
paramValues[0] = sharedLoader;
Method method =
startupInstance.getClass().getMethod(methodName, paramTypes);
method.invoke(startupInstance, paramValues);
catalinaDaemon = startupInstance;
}
initClassLoaders()方法
创建了commonLoader、catalinaLoader和sharedLoader
点击查看代码
private void initClassLoaders() {
try {
commonLoader = createClassLoader(\"common\", null);
if (commonLoader == null) {
// no config file, default to this loader - we might be in a \'single\' env.
commonLoader = this.getClass().getClassLoader();
}
catalinaLoader = createClassLoader(\"server\", commonLoader);
sharedLoader = createClassLoader(\"shared\", commonLoader);
} catch (Throwable t) {
handleThrowable(t);
log.error(\"Class loader creation threw exception\", t);
System.exit(1);
}
}
load()方法
通过反射调用catalinaDaemon的load()方法
点击查看代码
/**
* Load daemon.
*/
private void load(String[] arguments) throws Exception {
// Call the load() method
String methodName = \"load\";
Object param[];
Class<?> paramTypes[];
if (arguments==null || arguments.length==0) {
paramTypes = null;
param = null;
} else {
paramTypes = new Class[1];
paramTypes[0] = arguments.getClass();
param = new Object[1];
param[0] = arguments;
}
Method method =
catalinaDaemon.getClass().getMethod(methodName, paramTypes);
if (log.isDebugEnabled()) {
log.debug(\"Calling startup class \" + method);
}
method.invoke(catalinaDaemon, param);
}
start()方法
通过反射调用catalinaDaemon的start()方法
点击查看代码
/**
* Start the Catalina daemon.
* @throws Exception Fatal start error
*/
public void start() throws Exception {
if (catalinaDaemon == null) {
init();
}
Method method = catalinaDaemon.getClass().getMethod(\"start\", (Class [])null);
method.invoke(catalinaDaemon, (Object [])null);
}
来源：https://www.cnblogs.com/abing-orz/p/15414558.html
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