Web原生组件注入（Servlet、Filter、Listener）

Servlet原生组件

@WebServlet(urlPatterns = "/my")
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("servlet响应");
    }
}

在主启动类添加servlet扫描包路径：

@ServletComponentScan(basePackages = "com.chz.aaademo")	//添加servlet扫描包路径
@SpringBootApplication
public class AaademoApplication {

    public static void main(String[] args) {
        SpringApplication.run(AaademoApplication.class, args);
    }

}

servlet组件会跳过拦截器，直接进行响应。

Filter原生组件

@WebFilter(urlPatterns = "/css/*")
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("初始化过滤器");
    }

    @Override
    public void destroy() {
        System.out.println("过滤器销毁");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("过滤器工作");
        filterChain.doFilter(servletRequest,servletResponse);
    }
}

Listener原生组件

@WebListener
public class MyListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("ServletContextListener初始化");
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("ServletContextListener销毁");

    }
}

使用RegistrationBean

@Configuration(proxyBeanMethods = true) //默认为true，保证是单实例
public class MyRegisterConfig {

    @Bean
    public ServletRegistrationBean myServlet(){
        MyServlet myServlet = new MyServlet();
        return new ServletRegistrationBean(myServlet,"/my");
    }

    @Bean
    public FilterRegistrationBean myFilter(){
        MyFilter myFilter = new MyFilter();
//        return new FilterRegistrationBean(myFilter,MyServlet());
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(myFilter);
        filterRegistrationBean.setUrlPatterns(Arrays.asList("/my","/css/*"));
        return filterRegistrationBean;
    }

    @Bean
    public ServletListenerRegistrationBean myListener(){
        ServletContextListener servletContextListener = new MyListener();
        return new ServletListenerRegistrationBean(servletContextListener);
    }

}