重写四大组件干预Springboot的启动（菜鸟笔记）

川长思鸟来 2024-04-17 05:24 14阅读 0赞

## 重写四大组件干预Springboot的启动 ##

#### 文章目录 ####

*  重写四大组件干预Springboot的启动
 *   *  1. 四大组件
     *  2. 重写ApplicationContextInitializer
     *  3. 重写SpringApplicationRunListener
     *  4. 重写ApplicationRunner
     *  5. 重写CommandLineRunner
     *  6. 各个组件的执行时机

### 1. 四大组件 ###

//需要在META-INF/spring.factries配置
    ApplicationContextInitializer
    SpringApplicationRunListener
    
    //需要注入IOC容器
    ApplicationRunner
    CommandLineRunner

### 2. 重写ApplicationContextInitializer ###

package com.learn.boot.bootmaster.listener;
    
    import org.springframework.context.ApplicationContextInitializer;
    import org.springframework.context.ConfigurableApplicationContext;
    
    public class CustomApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
        
        @Override
        public void initialize(ConfigurableApplicationContext applicationContext) {
        
            System.out.println("CustomApplicationContextInitializer...initialize..." + applicationContext);
        }
    }

`需要在META-INF/spring.factories文件中进行配置`

# Initializers
    org.springframework.context.ApplicationContextInitializer=\
    com.learn.boot.bootmaster.listener.CustomApplicationContextInitializer

### 3. 重写SpringApplicationRunListener ###

package com.learn.boot.bootmaster.listener;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.SpringApplicationRunListener;
    import org.springframework.context.ConfigurableApplicationContext;
    import org.springframework.core.env.ConfigurableEnvironment;
    
    public class CustomSpringApplicationRunListener implements SpringApplicationRunListener {
        
    
        public CustomSpringApplicationRunListener(SpringApplication application, String[] args) {
        
        }
    
        @Override
        public void starting() {
        
            System.out.println("CustomSpringApplicationRunListener...starting...");
        }
    
        @Override
        public void environmentPrepared(ConfigurableEnvironment environment) {
        
            System.out.println("CustomSpringApplicationRunListener...environmentPrepared..." + environment.getSystemProperties().get("os.name"));
        }
    
        @Override
        public void contextPrepared(ConfigurableApplicationContext context) {
        
            System.out.println("CustomSpringApplicationRunListener...contextPrepared...");
        }
    
        @Override
        public void contextLoaded(ConfigurableApplicationContext context) {
        
            System.out.println("CustomSpringApplicationRunListener...contextLoaded...");
        }
    
        @Override
        public void started(ConfigurableApplicationContext context) {
        
            System.out.println("CustomSpringApplicationRunListener...started...");
        }
    
        @Override
        public void running(ConfigurableApplicationContext context) {
        
            System.out.println("CustomSpringApplicationRunListener...running...");
        }
    
        @Override
        public void failed(ConfigurableApplicationContext context, Throwable exception) {
        
            System.out.println("CustomSpringApplicationRunListener...failed...");
        }
    }

`需要在META-INF/spring.factories文件中进行配置`

`注坑：是org.springframework.boot.SpringApplicationRunListener，而不是org.springframework.context.SpringApplicationRunListener`

# Application Listeners
    org.springframework.boot.SpringApplicationRunListener=\
    com.learn.boot.bootmaster.listener.CustomSpringApplicationRunListener

### 4. 重写ApplicationRunner ###

`该组件不需要配置在META-INF/spring.factories文件中，只需要注入IOC容器即可`

package com.learn.boot.bootmaster.listener;
    
    import org.springframework.boot.ApplicationArguments;
    import org.springframework.boot.ApplicationRunner;
    import org.springframework.stereotype.Component;
    
    @Component
    public class CustomApplicationRunner implements ApplicationRunner {
        
        @Override
        public void run(ApplicationArguments args) throws Exception {
        
            System.out.println("CustomApplicationRunner...run..." + args);
        }
    }

### 5. 重写CommandLineRunner ###

package com.learn.boot.bootmaster.listener;
    
    import org.springframework.boot.CommandLineRunner;
    import org.springframework.stereotype.Component;
    
    import java.util.Arrays;
    
    @Component
    public class CustomCommandLineRunner implements CommandLineRunner {
        
        @Override
        public void run(String... args) throws Exception {
        
            System.out.println("CustomCommandLineRunner...run..." + Arrays.asList(args));
        }
    }

### 6. 各个组件的执行时机 ###

与上一章springboot启动源码执行顺序结合梳理

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