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

/*
 * 获取spring容器中bean工具类
 */
//这个注解的目的是为了把的SpringContextUtils的实例化交给Spring容器管理
@Component("springContextUtils")
public class SpringContextUtils implements ApplicationContextAware{
    
    
	private static ApplicationContext applicationContext = null;
	
	public static ApplicationContext getApplicationContext() {
    
    
		return applicationContext;
	}
	
	@SuppressWarnings("unchecked")
	public static <T> T getBean(String beanId) {
    
    
		return (T) applicationContext.getBean(beanId);
	}
	
	public static <T> T getBean(Class<T> requiredType) {
    
    
		return (T) applicationContext.getBean(requiredType);
	}
	
	/*
	 * Spring容器启动后，会把 applicationContext 给自动注入进来，然后我们把 applicationContext 赋值到静态变量中，方便后续拿到容器对象
	 * @see org.springframework.context.ApplicationContextAware#setApplicationContext(org.springframework.context.ApplicationContext)
	 */
	@Override
	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    
    
		SpringContextUtils.applicationContext = applicationContext;
		
	}

}