Filter,Servlet,Conponent如何获取ApplicationContext

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Filter 获取Context

在init()方法获取ServletContext，然后通过WebApplicationContextUtils.getWebApplicationContext(servletContext);

 public void init(FilterConfig filterConfig) throws ServletException {

        this.filterConfig = filterConfig;
        ServletContext servletContext = filterConfig.getServletContext();
        WebApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(servletContext);
        ssoClient = (SSOClient) ctx.getBean("ssoClient");
        springRedisClient = (IRedisClient) ctx.getBean("springRedisClient");

    }

 Servlet 通过WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());  

public class ContextServlet extends HttpServlet {  
     
    public ApplicationContext getApplicationContext(){  
        return WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());  
    }  
} 

 其他Component组件获取ApplicationContext，一般来说可直接通过注解获取，但是，假如面试的话，也要知道

实现ApplicationContextAware接口即可