SpringBoot之Servlet、Filter、Listener配置

在SpringBoot中是不需要配置web.xml的，那么原来在web.xml中配置的Servlet、Filter、Listener现在怎么弄呢？

SpringBoot提供了三种Bean FilterRegistrationBean、ServletRegistrationBean、ServletListenerRegistrationBean 
分别对应配置原生的Filter、Servlet、Listener。

 @Bean

    public ServletRegistrationBean indexServletRegistration() {

        ServletRegistrationBean registration = new ServletRegistrationBean(new IndexServlet());

        registration.addUrlMappings("/hello");

        return registration;

    }

    @Bean

    public FilterRegistrationBean indexFilterRegistration() {

        FilterRegistrationBean registration = new FilterRegistrationBean(new IndexFilter());

        registration.addUrlPatterns("/");

        return registration;

    }

    @Bean

    public ServletListenerRegistrationBean servletListenerRegistrationBean(){

        ServletListenerRegistrationBean servletListenerRegistrationBean = new ServletListenerRegistrationBean();

        servletListenerRegistrationBean.setListener(new IndexListener());

        return servletListenerRegistrationBean;

    }