springboot使用原生servlet,filter,listener

servlet

@Slf4j
@WebServlet(urlPatterns = {"/myServlet"})
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        log.info("myServlet调用了");
    }
}

filter

@Slf4j
@WebFilter(urlPatterns = {"/myServlet"})
public class myFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("myFilter初始化");
    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        log.info("myFilter拦截");
        filterChain.doFilter(servletRequest,servletResponse);
    }
}

listener

@Slf4j
@WebListener
public class myServletContextListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        log.info("myServletContextListener初始化");
    }
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        log.info("myServletContextListener销毁");
    }
}

如果单单这样学，原生servlet是不起作用的，必须在springboot启动接口中开启组件扫描ServletComponentScan

@SpringBootApplication
@ServletComponentScan(basePackages = {"com.godofball.boot"})
public class MainApplication {
    public static void main(String[] args) {
        ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args);
    }
}

或者使用springboot提供的类ServletRegistrationBean, FilterRegistrationBean, ServletListenerRegistrationBean

@Configuration
public class MyConfig implements WebMvcConfigurer {
    @Bean
    ServletRegistrationBean myServlet(){
        MyServlet myServlet = new MyServlet();
        return new ServletRegistrationBean(myServlet,"/myServlet");
    }
    @Bean
    FilterRegistrationBean myFilter(){
        MyFilter myFilter = new MyFilter();
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(myFilter);
        filterRegistrationBean.setServletRegistrationBeans(Arrays.asList(myServlet()));
        return filterRegistrationBean;
    }
    @Bean
    ServletListenerRegistrationBean myServletContextListener(){
        MyServletContextListener myServletContextListener = new MyServletContextListener();
        return new ServletListenerRegistrationBean(myServletContextListener);
    }
}

var code = "44c05181-3b7c-4cf6-8556-1cd8422e9527"