Tomcat 8（九）解读Tomcat组件的生命周期(Lifecycle)

最新推荐文章于 2022-10-19 23:22:30 发布

flyliuweisky547

最新推荐文章于 2022-10-19 23:22:30 发布

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分类专栏： Tomcat 8 深入学习Tomcat 8 文章标签： tomcat Lifecycle

本文链接：https://blog.youkuaiyun.com/flyliuweisky547/article/details/24431993

本文详细解析了Tomcat 8中组件的生命周期管理，包括Lifecycle接口、LifecycleState枚举、LifecycleEvent实体类和LifecycleListener监听器。通过LifecycleBase和LifecycleMBeanBase的实现，阐述了组件从初始化、启动、停止到销毁的过程，以及如何通过监听器监听和响应组件状态变化。特别提到了StandardServer的initInternal方法，展示了Tomcat如何通过启动最顶层组件来启动所有组件。

Tomcat 8（七）解读Bootstrap介绍过，执行startup.bat，将引发Tomcat一连串组件的启动。其实这一连串启动是通过组件的生命周期(Lifecycle)实现的

今天来看看Lifecycle设计。解读Lifecycle，涉及到如下几个类

Lifecycle、LifecycleState、LifecycleEvent、LifecycleListener(位于org.apache.catalina)

LifecycleBase、LifecycleSupport、LifecycleMBeanBase(位于org.apache.catalina.util)

Lifecycle接口

package org.apache.catalina;

public interface Lifecycle {

    public static final String BEFORE_INIT_EVENT = "before_init";
    public static final String AFTER_INIT_EVENT = "after_init";
    public static final String START_EVENT = "start";
    public static final String BEFORE_START_EVENT = "before_start";
    public static final String AFTER_START_EVENT = "after_start";
    public static final String STOP_EVENT = "stop";
    public static final String BEFORE_STOP_EVENT = "before_stop";
    public static final String AFTER_STOP_EVENT = "after_stop";
    public static final String AFTER_DESTROY_EVENT = "after_destroy";
    public static final String BEFORE_DESTROY_EVENT = "before_destroy";
    public static final String PERIODIC_EVENT = "periodic";
    public static final String CONFIGURE_START_EVENT = "configure_start";
    public static final String CONFIGURE_STOP_EVENT = "configure_stop";

    public void addLifecycleListener(LifecycleListener listener);

    public LifecycleListener[] findLifecycleListeners();

    public void removeLifecycleListener(LifecycleListener listener);

    public void init() throws LifecycleException;

    public void start() throws LifecycleException;

    public void stop() throws LifecycleException;

    public void destroy() throws LifecycleException;

    publ