[Java知识库]如何在sprinboot容器启动的时候，去监听容器的过程，然后做一些事情呢

1、在项目的classpath目录下面加上这个东西，springboot启动的时候，其实会去加载这个文件的

2、编写对应的类：

package com.cqupt.annotation.listener;

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.SpringApplicationRunListener;
import org.springframework.boot.context.event.EventPublishingRunListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.stereotype.Component;

@Slf4j
public class mySpringApplicationRunListener implements SpringApplicationRunListener {
    private final SpringApplication application;
    private final String[] args;


    public mySpringApplicationRunListener(SpringApplication application, String[] args) {
        this.application = application;
        this.args = args;
    }

    @Override
    public void starting() {
        log.info("starting***************************************************");
    }

    @Override
    public void environmentPrepared(ConfigurableEnvironment environment) {
        log.info("environmentPrepared***************************************************");
    }

    @Override
    public void contextPrepared(ConfigurableApplicationContext context) {
        log.info("contextPrepared***************************************************");
    }

    @Override
    public void contextLoaded(ConfigurableApplicationContext context) {
        log.info("contextLoaded***************************************************");
    }

    @Override
    public void started(ConfigurableApplicationContext context) {
        log.info("started***************************************************");
    }

    @Override
    public void running(ConfigurableApplicationContext context) {
        log.info("running***************************************************");
    }

    @Override
    public void failed(ConfigurableApplicationContext context, Throwable exception) {
        log.info("failed***************************************************");
        
    }


}

3、那为什么这个类会生效呢？
看下面的这段代码：

		SpringApplication.run(CustomAnnotationWebApplication.class, args);
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\/


	public static ConfigurableApplicationContext run(Class<?> primarySource,
			String... args) {
		return run(new Class<?>[] { primarySource }, args);
	}
	
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	public static ConfigurableApplicationContext run(Class<?>[] primarySources,
			String[] args) {
		return new SpringApplication(primarySources).run(args);
	}
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\/

{
		StopWatch stopWatch = new StopWatch();
		stopWatch.start();
		ConfigurableApplicationContext context = null;
		Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
		configureHeadlessProperty();
		SpringApplicationRunListeners listeners = getRunListeners(args);
		//看这里，看这里，看这里，这里就会去调用你写的监听哦
		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);
			afterRefresh(context, applicationArguments);
			stopWatch.stop();
			if (this.logStartupInfo) {
				new StartupInfoLogger(this.mainApplicationClass)
						.logStarted(getApplicationLog(), stopWatch);
			}
			listeners.started(context);
			callRunners(context, applicationArguments);
		}
		catch (Throwable ex) {
			handleRunFailure(context, ex, exceptionReporters, listeners);
			throw new IllegalStateException(ex);
		}

		try {
			listeners.running(context);
		}
		catch (Throwable ex) {
			handleRunFailure(context, ex, exceptionReporters, null);
			throw new IllegalStateException(ex);
		}
		return context;
	}