SpringBoot基础-初始化器自定义实现_springbootinitializer 中版本自定义-优快云博客

本文链接：https://blog.youkuaiyun.com/cen50958/article/details/112392816

本文介绍了如何自定义SpringBoot初始化器，包括实现ApplicationContextInitializer接口，通过META-INF/spring.factories配置，以及在application.yml中配置。同时讨论了初始化顺序：application.properties > META-INF/spring.factories > SpringApplication类初始化，并解释了Order值对执行顺序的影响。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

自定义初始化器实现

实现 ApplicationContextInitializer接口

@Order(1)
public class FirstInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        ConfigurableEnvironment environment = applicationContext.getEnvironment();
        Map<String, Object> map = new HashMap<>();
        map.put("key1", "first");
        MapPropertySource mapPropertySource = new MapPropertySource("firstInitializer", map);
        environment.getPropertySources().addLast(mapPropertySource);
        System.out.println("run FirstInitializer");
    }
}

加载到springboot中

META-INF文件夹下spring.factories内填写接口实现(FirstInitializer)

在resources下新建META-INF文件夹，新建spring.factories中定义，key为：org.springframework.context.ApplicationContextInitializer

org.springframework.context.ApplicationContextInitializer=com.demo.silly.spring.boot.initializer.FirstInitializer

在这里插入图片描述

通过SpringApplication类初始化后设置进去(SecondInitializer)

@SpringBootApplication
public class SpringBootDemoApplication {
    public static void main(String[] args) {
//		SpringApplication.run(SpringBootDemoApplication.class, args);

        SpringApplication springApplication = new SpringApplication((SpringBootDemoApplication.class));
        springApplication.addInitializers(new SecondInitializer());
        springApplication.run(args);
    }
}

在application.yml种配置(ThreeInitializer)

application.properties 内填写接口实现，key为:context.initializer.classes

context:
  initializer:
    classes: com.demo.silly.spring.boot.initializer.ThreeInitializer

获取参数方式

代码获取

@Component
public class SpringUtils implements ApplicationContextAware {

    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    /**
     * 获取属性
     *
     * @param key
     * @return
     */
    public String get(String key) {
        return applicationContext.getEnvironment().getProperty(key);
    }
}

属性值获取
```
@Value("${key1}")
private String key1;
```

顺序结果

run ThreeInitializer
run FirstInitializer
run SecondInitializer

由执行打印的顺序可以得出：

application.properties > META-INF下spring.factories > SpringApplication类初始化后设置
Order值越小越先执行

系统初始化器的实现原理