SpringBoot几个重要的事件回调、监听机制

（1）、需要配置在META-INF/Spring.factories

　　1.ApplicationContextInitializer

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package org.springframework.context;

public interface ApplicationContextInitializer<C extends ConfigurableApplicationContext> {
    //监听ioc容器启动
    void initialize(C var1);
}

　　2.SpringApplicationRunListener 

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package org.springframework.boot;

import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.env.ConfigurableEnvironment;

public interface SpringApplicationRunListener {
    //监听容器开始
    void starting();
    //SpringBoot环境准备好
    void environmentPrepared(ConfigurableEnvironment environment);
    //ioc容器准备好了
    void contextPrepared(ConfigurableApplicationContext context);
    //容器环境加载完成
    void contextLoaded(ConfigurableApplicationContext context);

    void started(ConfigurableApplicationContext context);

    void running(ConfigurableApplicationContext context);
    //SpringBoot创建完成
    void failed(ConfigurableApplicationContext context, Throwable exception);
}

（2）、只需要放到ioc容器中即可

　　1.ApplicationRunner 

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package org.springframework.boot;

@FunctionalInterface
public interface ApplicationRunner {
    void run(ApplicationArguments args) throws Exception;
}

　　2.CommandLineRunner 

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package org.springframework.boot;

@FunctionalInterface
public interface CommandLineRunner {
    void run(String... args) throws Exception;
}