Spring获取上下文的四种方式方式

获取Spring的上下文，并设置在ApplicationContextStore中

import org.springframework.context.ApplicationContext;

public class ApplicationContextStore {

    private static ApplicationContext applicationContext;

    public static void setApplicationContext(ApplicationContext applicationContext) {
        ApplicationContextStore.applicationContext = applicationContext;
    }

    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }
}

---

第一种：使用ApplicationContextInitializer接口，让SpringApplication启动时进行回调，然后获取ApplicationContext。

1、创建接口

import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ConfigurableApplicationContext;

public class UseInit implements ApplicationContextInitializer<ConfigurableApplicationContext> {

    @Override
    public void initialize(ConfigurableApplicationContext configurableApplicationContext) {
        ApplicationContextStore.setApplicationContext(configurableApplicationContext);
    }
}

2、注册接口

@SpringBootApplication
public class SpringdemoApplication {

    public static void main(String[] args) {
        //SpringApplication.run(SpringdemoApplication.class, args);
        SpringApplication application = new SpringApplication(SpringdemoApplication.class);
        application.addInitializers(new UseInit());
        application.run(args);
    }
}

---

第二种：使用ApplicationListener接口，当SpringApplication启动时候，对ApplicationContextEvent事件进行监听然后回调接口，获取ApplicationContext。

@Component
public class UseListener implements ApplicationListener<ApplicationContextEvent> {
    @Override
    public void onApplicationEvent(ApplicationContextEvent applicationContextEvent) {
        ApplicationContextStore.setApplicationContext(applicationContextEvent.getApplicationContext());
    }
}

需要注意对是，需要注册为Spring的Bean，由SpringApplication正常启动时自动获取。

---

第三种：SpringApplication启动时，return出来的就是ApplicationContext。

@SpringBootApplication
public class SpringdemoApplication {

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(SpringdemoApplication.class, args);
        ApplicationContextStore.setApplicationContext(context);
    }
}

---

第四种：使用SpringApplicationAware，利用Spring的Bean周期，在Bean初始化的时候获取ApplicationContext。

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class UseAware implements ApplicationContextAware {
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        ApplicationContextStore.setApplicationContext(applicationContext);
    }
}