[Tomcat] Chapter 5: Source Analysis of Tomcat Startup Process (Part I) Main Entry

Tomcat runs the entry method of the entry class BootStrap, that is, the startup method; the startup of Tomcat is divided into two parts, init and start

• init: the initialization phase, that is, the initialization method of each component will be called in turn
  • InitInternal: Standard~, Connector; because they inherited LifeCycleBase, the init method is implemented in template mode
  • init: ProtocolHandler is an enum, Endpoint is an abstract class; they all define init by themselves, not LifeCycle's init
• start: The operating phase, that is, the start method of each component will be called in turn
  • startInternal: Standard~, Connector; because they inherited LifeCycleBase, the start method is implemented in template mode
  • start: ProtocolHandler is an enum, Endpoint is an abstract class; they all define start by themselves, not the start of LifeCycle

public static void main(String args[]) {
    
    
    	//1.初始化阶段  init()
        if (daemon == null) {
    
    
            // Don't set daemon until init() has completed
            Bootstrap bootstrap = new Bootstrap();
            try {
    
    
                // 调用init（）初始化BootStrap
                bootstrap.init();
            } catch (Throwable t) {
    
    
                handleThrowable(t);
                t.printStackTrace();
                return;
            }
            // 将守护线程bootstop赋给守护线程daemon
            daemon = bootstrap;
        } else {
    
    
            Thread.currentThread().setContextClassLoader(daemon.catalinaLoader);
        }
    	//2.运行阶段  start()
        try {
    
    
            String command = "start";
            if (args.length > 0) {
    
    
                command = args[args.length - 1];
            }

            if (command.equals("startd")) {
    
    
                args[args.length - 1] = "start";
                // deamon.load(args)，实际上会去调用Catalina#load(args)方法，
                // 会去初始化一些资源，优先加载conf/server.xml，找不到再去加载server-embed.xml；
                // 此外，load方法还会初始化Server
                daemon.load(args);
                // daemon.start()，实例上是调用Catalina.start()
                daemon.start();
              // 输入stop命令就停止
            } 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();
            } 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);
        }
}