SpringBoot 整合Servlet、Filter和Listener

布满荆棘的人生 2022-01-30 00:43 346阅读 0赞

SpringBoot 整合Servlet、Filter和Listener，都有两种方式

## 方式一采用注解 ##

### 一、SpringBoot和Servlet整合 ###

**1、用注解整合**

1）创建一个Servlet类继承HttpServlet类，用注解@WebServlet配置Servlet映射

@WebServlet(urlPatterns = "/index")
    public class IndexServlet extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            doPost(req, resp);
        }
    
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            System.out.println("IndexServlet 的doXxx() 方法被调用了...");
            resp.getWriter().print("IndexServlet doXxx()！");
        }
    }

2）在SpringBoot的启动类上加注解@ServletComponentScan，扫描注解并初始化

@SpringBootApplication
    @ServletComponentScan
    public class Springbootdemo1Application {
        public static void main(String[] args) {
            SpringApplication.run(Springbootdemo1Application.class, args);
        }
    }

### 二、SpringBoot和Filter整合 ###

**1、用注解整合**

1）创建一个MyFilter类实现Filter，用注解@WebFilter配置Filter映射

@WebFilter(filterName = "MyFilter", urlPatterns = {"/index"})
    public class MyFilter implements Filter {
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
            System.out.println("init...");
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
            HttpServletRequest req = (HttpServletRequest) servletRequest;
            String url = req.getRequestURI();
            //拦截器配置拦截有所url地址的时候/*,会出现连续拦截两次的情况，原因是因为浏览器发出访问了图标favicon.ico的请求
            if(url.contains("favicon.ico")){
                return;
            }
            System.out.println("doFilter...进来了");
            filterChain.doFilter(servletRequest,servletResponse);
            System.out.println("doFilter...出去了");
        }
    
        @Override
        public void destroy() {
            System.out.println("destroy...");
        }
    }

2）在SpringBoot的启动类上加注解@ServletComponentScan，扫描注解并初始化

### 三、SpringBoot和Listener整合 ###

**常用的Web事件的六大监听接口如下：**

ServletContextListener：用于监听Web的启动及关闭

ServletContextAttributeListener：用于监听ServletContext范围内属性的改变

ServletRequestListener：用于监听用户请求

ServletRequestAttributeListener：用于监听ServletRequest范围属性的改变

HttpSessionListener：用于监听用户session的开始及结束

HttpSessionAttributeListener：用于监听HttpSession范围内的属性改变

**1、用注解整合**

1）创建一个MyListernner类实现六大监听接口之一即可（根据业务），用注解@WebListener配置Listernner映射

@WebListener
    public class MyListernner implements ServletContextListener {
        @Override
        public void contextInitialized(ServletContextEvent sce) {
            System.out.println("MyListernner初始化啦...");
        }
    
        @Override
        public void contextDestroyed(ServletContextEvent sce) {
            System.out.println("MyListernner摧毁啦...");
        }
    }

2）在SpringBoot的启动类上加注解@ServletComponentScan，扫描注解并初始化

![20190517151119227.png][]   ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyNDAyODU0_size_16_color_FFFFFF_t_70][]  ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyNDAyODU0_size_16_color_FFFFFF_t_70 1][]

## ##

## 方式二采用Spring注册Servlet、Filter和Listener（推荐使用） ##

**创建的Servlet、Filter和Listener都不使用那些映射与扫描注解，只需要在@Configuration类中加入类似以下的代码即可注入。**

public class IndexServlet extends HttpServlet {
    ...
    }

@Configuration
    public class WebConfig {
    
        @Bean
        public ServletRegistrationBean getIndexServletBean(){
            ServletRegistrationBean bean = new ServletRegistrationBean(new IndexServlet());
            bean.addUrlMappings("/index");
            return bean;
        }
    
        @Bean
        public FilterRegistrationBean getMyFilterBean(){
            FilterRegistrationBean bean = new FilterRegistrationBean(new MyFilter());
            bean.addUrlPatterns("/*");
            return bean;
        }
    
        @Bean
        public ServletListenerRegistrationBean getMyListennerBean(){
            ServletListenerRegistrationBean bean = new ServletListenerRegistrationBean(new MyListernner());
            return bean;
        }
    
    }

效果和方式一相同

**常用的Web事件的六大监听接口使用：**[六大监听器的web简单使用][web]

end~

[20190517151119227.png]: https://img-blog.csdnimg.cn/20190517151119227.png
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[web]: https://blog.csdn.net/qq_42402854/article/details/86156879