SpringBoot原生组件注入实现两种方式介绍

@WebServlet(urlPatterns = "/my") // 加入 @WebServlet 注释
public class MyServlet extends httpservlet { // 注意要继承 HttpServlet 类
    @Override // 重写 DoGet 方法
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().println("haha");
    }
}

@ServletComponentScan(basePackages = "com.wanqing.admin") //扫描那个包中有servlet
@SpringBootApplication
public class DemoAdminApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoAdminApplication.class, args);
    }
}

@Slf4j
@WebFilter(urlPatterns = {"/CSS/*", "/images/*"}) // 拦截静态资源
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        Filter.super.init(filterConfig);
        log.info("MyFilter初始化完成");
    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("MyFilter工作");
        filterChain.doFilter(servletRequest, servletResponse);
    }
    @Override
    public void destroy() {
        Filter.super.destroy();
        log.info("MyFilter销毁");
    }
}

@WebListener
@Slf4j
public class MyServletContextListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        log.info("MyServletContextListener 监听到项目初始化完成");
    }
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        log.info("MyServletContextListener 监听到项目销毁");
    }
}

@Configuration
public class MyRegistConfig {
    @Bean
    public ServletRegistrationBean myServlet(){
        MyServlet myServlet = new MyServlet();
        return new ServletRegistrationBean(myServlet, "/my","/my02");
    }
    @Bean
    public FilterRegistrationBean myFilter(){
        MyFilter filter = new MyFilter();
        //return new FilterRegistrationBean(filter, myServlet()); // 拦截myServlet()的路径
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(filter);
        filterRegistrationBean.addUrlPatterns("/my","/css/*");
        return filterRegistrationBean;
    }
    @Bean
    public ServletListenerRegistrationBean myListener(){
        MyServletContextListener myServletContextListener = new MyServletContextListener();
        return new ServletListenerRegistrationBean(myServletContextListener);

    }
}

		@Bean(name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME) // 注册 DispatcherServlet  组件
		public DispatcherServlet dispatcherServlet(WebMvcProperties webMvcProperties) {
			DispatcherServlet dispatcherServlet = new DispatcherServlet();
			dispatcherServlet.setDispatchOptionsRequest(webMvcProperties.isDispatchOptionsRequest());
			dispatcherServlet.setDispatchTraceRequest(webMvcProperties.isDispatchTraceRequest());
			dispatcherServlet.setThrowExceptionIfNoHandlerFound(webMvcProperties.isThrowExceptionIfNoHandlerFound());
			dispatcherServlet.setPublishEvents(webMvcProperties.isPublishRequestHandledEvents());
			dispatcherServlet.setEnableLoggingRequestDetails(webMvcProperties.isLogRequestDetails());
			return dispatcherServlet;
		}

		@Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)
		@ConditionalOnBean(value = DispatcherServlet.class, name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
		public DispatcherServletRegistrationBean dispatcherServletRegistration(DispatcherServlet dispatcherServlet,
				WebMvcProperties webMvcProperties, ObjectProvider<MultipartConfigElement> multipartConfig) {
			DispatcherServletRegistrationBean registration = new DispatcherServletRegistrationBean(dispatcherServlet,
					webMvcProperties.getServlet().getPath()); // 拿到默认映射路径为 / 路径
			registration.setName(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
			registration.setLoadOnStartup(webMvcProperties.getServlet().getLoadOnStartup());
			multipartConfig.ifAvailable(registration::setMultipartConfig);
			return registration;
		}