Oliver's Blog

Spring容器ApplicationContext放到静态变量

  • Apr 01, 2018

设置方式

Spring Boot启动类设置

public class ApplicationContextHolder {  
    public static ApplicationContext applicationContext;
}

public class DoubucketItemsApplication {  
    public static void main(String[] args) {  
        ApplicationContextHolder.applicationContext = SpringApplication.run(DoubucketItemsApplication.class, args);
    }  
}

容器事件处理程序设置

@Component  
@AllArgsConstructor  
public class ApplicationContextHolder implements ApplicationRunner {  
    public static ApplicationContext applicationContext;  
  
    private ApplicationContext context;  
  
    @Override  
    public void run(ApplicationArguments args) {  
        applicationContext = context;  
    }  
}

ApplicationContextAware设置

@Component
public class ApplicationContextHolder implements ApplicationContextAware {
    private static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {  
        ApplicationContextHolder.applicationContext = applicationContext;  
    }
    
    public static <T> T getBean(Class<T> clazz) {  
        return applicationContext.getBean(clazz);  
    }

    public static Object getBean(String beanName) {  
        return applicationContext.getBean(beanName);  
    }
}

volatile问题

尚未确认设置applicationContext的操作是否与后续的读取有happens-before关系，保险的话可以为变量加上volatile

private static volatile ApplicationContext applicationContext;

bean创建次序问题

当需要保证ApplicationContextHolder优先被创建时，需要使用如@Order(value = Integer.MIN_VALUE)的方式保证优先级，数字越小优先级越高。

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