在Spring Boot中&＃xff0c;当需要以注解的方式添加session监听器、过滤器时&＃xff0c;为了让其生效&＃xff0c;还需要在配置类上添加&＃64;ServletComponentScan注解&＃xff0c;该注解的作用是告诉spring boot,让其自动管理servlet&＃xff0c;否则注解方式注册的servlet不起作用

/*** 注册Servlet. 不需要添加注解&＃xff1a;&＃64;ServletComponentScan* &＃64;return*/&＃64;Beanpublic ServletRegistrationBean demoServlet(){ServletRegistrationBean registrationBean &＃61; new ServletRegistrationBean();registrationBean.setServlet(new DemoServlet());registrationBean.addUrlMappings("/demoServlet");return registrationBean;}

package cn.wuweixiang.springbootdemo.servlet;import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;/*** DemoServlet** &＃64;author weixiang.wu* &＃64;date 2018-08-22 20:34**/
public class DemoServlet extends HttpServlet {&＃64;Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) {System.out.println(">>>>>>>>>>doGet()<<<<<<<<<<<");}&＃64;Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {System.out.println(">>>>>>>>>>doPost()<<<<<<<<<<<");resp.setContentType("text/html");PrintWriter out &＃61; resp.getWriter();out.println("");out.println("");out.println("");out.println("");out.println("");out.println("

这是&＃xff1a;DemoServlet

/*** 1.使用ServletListenerRegistrationBean注册Listener&＃xff0c;只需要在&＃64;Configuration类中加入即可* 2.直接使用&＃64;WebFilter* &＃64;return*/
// &＃64;Bean
// public ServletListenerRegistrationBean myServletListener() {
// ServletListenerRegistrationBean demoListener &＃61; new ServletListenerRegistrationBean();
// demoListener.setListener(new DemoListener());
// return demoListener;
// }


package cn.wuweixiang.springbootdemo.listener;import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;/*** DemoListener** &＃64;author weixiang.wu* &＃64;date 2018-08-22 20:49**/
&＃64;WebListener
public class DemoListener implements ServletContextListener {&＃64;Overridepublic void contextInitialized(ServletContextEvent sce) {System.err.println("DemoListener.contextInitialized");}&＃64;Overridepublic void contextDestroyed(ServletContextEvent sce) {System.err.println("DemoListener.contextDestroyed");}
}
三、添加过滤器

/*** 1.使用FilterRegistrationBean注册Filter&＃xff0c;只需要在&＃64;Configuration类中加入即可* 2.直接使用&＃64;WebFilter* &＃64;see DemoFilter* &＃64;return*/
// &＃64;Bean
// public FilterRegistrationBean demoFilter() {
// FilterRegistrationBean demoFilter &＃61; new FilterRegistrationBean();
// demoFilter.addUrlPatterns("/*");
// demoFilter.setFilter(new DemoFilter());
// return demoFilter;
// }

package cn.wuweixiang.springbootdemo.filter;import org.springframework.core.annotation.Order;import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;/*** DemoFilter** &＃64;author weixiang.wu* &＃64;date 2018-08-22 20:43**/
&＃64;WebFilter(urlPatterns &＃61; "/*")
/** Lower values have higher priority.*/
&＃64;Order(value &＃61; 1)
public class DemoFilter implements Filter {&＃64;Overridepublic void init(FilterConfig filterConfig) throws ServletException {System.err.println("DemoFilter.init");}&＃64;Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {System.err.println("DemoFilter.doFilter");}&＃64;Overridepublic void destroy() {System.err.println("DemoFilter.destroy");}
}