Spring源码10. 启动完成, 发布ApplicationStartedEvent, ApplicationReadyEvent事件

上篇回顾

在上一篇refreshContext()刷新应用上下文中, 我们主要分析了spring容器的刷新

1. 首先更新刷新状态
2. 然后处理beanFactory的后置处理器, 用于注册bean定义, 其中ConfigurationClassPostProcessor处理器, 处理模块中@Configuration注解
3. onRefresh()方法中, 实例化了TomcatWebServer
4. 最后在finishRefresh()中, 实例化了所有bean

---

目录

1. 启动完成

2. 发布ApplicationStartedEvent事件

3. 发布ApplicationReadyEvent事件

4. 异常处理 handleRunFailure

---

1. 启动完成

主要发布了ApplicationStartedEvent, ApplicationReadyEvent事件, 以及启动失败异常处理, 发布启动失败事件

public class SpringApplication {
    public ConfigurableApplicationContext run(String... args) {
        StopWatch stopWatch = new StopWatch();
        stopWatch.start();
        ConfigurableApplicationContext context = null;
        Collection exceptionReporters = new ArrayList<>();
        configureHeadlessProperty();
        SpringApplicationRunListeners listeners = getRunListeners(args);
        listeners.starting();
        try {
            ApplicationArguments applicationArguments = new DefaultApplicationArguments(
                    args);
            ConfigurableEnvironment environment = prepareEnvironment(listeners,
                    applicationArguments);
            configureIgnoreBeanInfo(environment);
            Banner printedBanner = printBanner(environment);
            context = createApplicationContext();
            exceptionReporters = getSpringFactoriesInstances(
                    SpringBootExceptionReporter.class,
                    new Class[] { ConfigurableApplicationContext.class }, context);
            prepareContext(context, environment, listeners, applicationArguments,
                    printedBanner);
            refreshContext(context);
            
            //本文分析的是下面所有代码
            
            //没有执行任何操作
            afterRefresh(context, applicationArguments);
            //打印启动时间日志
            stopWatch.stop();
            if (this.logStartupInfo) {
                //打印启动信息
                new StartupInfoLogger(this.mainApplicationClass)
                        .logStarted(getApplicationLog(), stopWatch);
            }
            //发布ApplicationStartedEvent事件
            listeners.started(context);
            callRunners(context, applicationArguments);
        }
        catch (Throwable ex) {
            //异常处理
            handleRunFailure(context, ex, exceptionReporters, listeners);
            throw new IllegalStateException(ex);
        }

        try {
            //发布ApplicationReadyEvent事件
            listeners.running(context);
        }
        catch (Throwable ex) {
            //异常处理
            handleRunFailure(context, ex, exceptionReporters, null);
            throw new IllegalStateException(ex);
        }
        return context;
    }
}

2. 发布ApplicationStartedEvent事件

有两个listener关注了ApplicationStartedEvent事件,

1. BackgroundPreinitializer
   • 扩展点, 暂不做任何处理
2. DelegatingApplicationListener
   • 扩展点, 暂不做任何处理

3. 发布ApplicationReadyEvent事件

有三个监听器关注了ApplicationReadyEvent事件

1. SpringApplicationAdminMXBeanRegistrar
   • this.ready设为true
2. BackgroundPreinitializer
   • 等待或者终止后台线程
3. DelegatingApplicationListener
   • 扩展点, 暂不做任何处理

4. 异常处理 handleRunFailure

public class SpringApplication {

    //处理异常
    private void handleRunFailure(ConfigurableApplicationContext context,
            Throwable exception,
            Collection exceptionReporters,
            SpringApplicationRunListeners listeners) {
        try {
            try {
                //获取exitCode编码
                handleExitCode(context, exception);
                //发布启动失败事件
                if (listeners != null) {
                    listeners.failed(context, exception);
                }
            }
            finally {
                //上报失败, 交给exceptionReporters处理
                reportFailure(exceptionReporters, exception);
                if (context != null) {
                    context.close();
                }
            }
        }
        catch (Exception ex) {
            logger.warn("Unable to close ApplicationContext", ex);
        }
        //抛出异常
        ReflectionUtils.rethrowRuntimeException(exception);
    }
}

总结

到这一步, 整个springboot的启动已经结束, 最后发布了ApplicationStartedEvent, ApplicationReadyEvent事件, 以及启动失败异常处理, 发布启动失败事件