Spring Boot 之Servlet、Listener、Filter

最新推荐文章于 2025-09-03 23:14:03 发布

转载最新推荐文章于 2025-09-03 23:14:03 发布 · 137 阅读

0 ·

CC 4.0 BY-SA版权

原文链接：https://my.oschina.net/wuweixiang/blog/1932417

文章标签：

#java #python

本文介绍了如何在SpringBoot项目中通过@Bean方式配置自定义Servlet、监听器和过滤器，并探讨了不同配置方法及其效果。

2019独角兽企业重金招聘Python工程师标准>>>

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

一、添加自定义Servlet


	/**
	 * 注册Servlet. 不需要添加注解：@ServletComponentScan
	 * @return
	 */
	@Bean
	public ServletRegistrationBean demoServlet(){
		ServletRegistrationBean registrationBean = 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
 *
 * @author weixiang.wu
 * @date 2018-08-22 20:34
 **/
public class DemoServlet extends HttpServlet {

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(">>>>>>>>>>doGet()<<<<<<<<<<<");
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
		System.out.println(">>>>>>>>>>doPost()<<<<<<<<<<<");
		resp.setContentType("text/html");
		PrintWriter out = resp.getWriter();
		out.println("<html>");
		out.println("<head>");
		out.println("<title>Hello World</title>");
		out.println("</head>");
		out.println("<body>");
		out.println("<h1>这是：DemoServlet</h1>");
		out.println("</body>");
		out.println("</html>");
	}
}

二、添加监听器

	/**
	 *  1.使用ServletListenerRegistrationBean注册Listener，只需要在@Configuration类中加入即可
	 *  2.直接使用@WebFilter
	 * @return
	 */
//	@Bean
//	public ServletListenerRegistrationBean<DemoListener> myServletListener() {
//		ServletListenerRegistrationBean<DemoListener> demoListener = new ServletListenerRegistrationBean<DemoListener>();
//		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
 *
 * @author weixiang.wu
 * @date 2018-08-22 20:49
 **/
@WebListener
public class DemoListener implements ServletContextListener {
	@Override
	public void contextInitialized(ServletContextEvent sce) {
		System.err.println("DemoListener.contextInitialized");
	}

	@Override
	public void contextDestroyed(ServletContextEvent sce) {
		System.err.println("DemoListener.contextDestroyed");
	}
}

三、添加过滤器

	/**
	 * 1.使用FilterRegistrationBean注册Filter，只需要在@Configuration类中加入即可
	 * 2.直接使用@WebFilter
	 * @see DemoFilter
	 * @return
	 */
//	@Bean
//	public FilterRegistrationBean demoFilter() {
//		FilterRegistrationBean demoFilter = 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
 *
 * @author weixiang.wu
 * @date 2018-08-22 20:43
 **/
@WebFilter(urlPatterns = "/*")
/** Lower values have higher priority.*/
@Order(value = 1)
public class DemoFilter implements Filter {
   @Override
   public void init(FilterConfig filterConfig) throws ServletException {
      System.err.println("DemoFilter.init");
   }

   @Override
   public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
      System.err.println("DemoFilter.doFilter");
   }

   @Override
   public void destroy() {
      System.err.println("DemoFilter.destroy");
   }
}

转载于:https://my.oschina.net/wuweixiang/blog/1932417