SpringBoot系列<八>过滤器filter和监听器listener配置

Love The Way You Lie 2022-06-03 05:10 233阅读 0赞

## 一、过滤器 ##

**1、新建过滤器类实现Filter接口**

package com.jd.m.tg.filter;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Component;
    
    import javax.servlet.*;
    import java.io.IOException;
    
    @Component
    public class MyFilter implements Filter { 
    
        private static final Logger LOG= LoggerFactory.getLogger(MyFilter.class);
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
            LOG.info("初始化过滤器");
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
            LOG.info("过滤器处理规则");
            filterChain.doFilter(servletRequest,servletResponse);
        }
    
        @Override
        public void destroy() {
            LOG.info("销毁过滤器");
        }
    }

**2、filter配置**

SpringBoot的filter配置有两种方式，一种是@Webfilter注解方式，一种是FilterRegistrationBean配置类，推荐第二种方式，因为注解的底层也是通过第二种方式实现的，对于多个过滤器的执行顺序也好设置；order值越小，表示越优先执行；

package com.jd.m.tg.config;
    
    import com.jd.m.tg.filter.MyFilter;
    import com.jd.m.tg.filter.MyFilterTwo;
    import lombok.AllArgsConstructor;
    import org.springframework.boot.web.servlet.FilterRegistrationBean;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    @Configuration
    @AllArgsConstructor
    public class FilterConfig {
    
        private MyFilter myFilter;
        private MyFilterTwo myFilterTwo;
    
        @Bean
        public FilterRegistrationBean myFilterRegistration() {
            FilterRegistrationBean registration = new FilterRegistrationBean();
            registration.setFilter(myFilter);
            registration.addUrlPatterns("/*");
            registration.setName("myFilter");
            registration.setOrder(10);
            return registration;
        }
    
        @Bean
        public FilterRegistrationBean myTwoFilterRegistration() {
            FilterRegistrationBean registration = new FilterRegistrationBean();
            registration.setFilter(myFilterTwo);
            registration.addUrlPatterns("/*");
            registration.setName("myFilterTwo");
            registration.setOrder(1);
            return registration;
        }
    }

**注：filter、listener、servlet都需要在启动类上加上注解@ServletComponentScan**

--------------------

二、监听器配置

1、新建监听器（只列举一种监听器实现方式，有很多种监听器）

package com.jd.m.tg.listener;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Component;
    
    import javax.servlet.ServletContextEvent;
    import javax.servlet.ServletContextListener;
    
    
    @Component
    public class MyListener implements ServletContextListener { 
    
        private static final Logger LOG= LoggerFactory.getLogger(MyListener.class);
    
        @Override
        public void contextInitialized(ServletContextEvent servletContextEvent) {
            LOG.info("ServletContextListener监听器初始化");
        }
    
        @Override
        public void contextDestroyed(ServletContextEvent servletContextEvent) {
            LOG.info("ServletContextListener监听器销毁");
        }
    }

2、监听器配置

可以在监听器类上加@WebListener实现配置，但ServletListenerRegistrationBean实现配置更好，原理同上，看习惯；

package com.jd.m.tg.config;
    
    import com.jd.m.tg.listener.MyListener;
    import com.jd.m.tg.listener.MyListenerTwo;
    import lombok.AllArgsConstructor;
    import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    
    @Configuration
    @AllArgsConstructor
    public class ListenerConfig {
    
        private MyListener myListener;
        private MyListenerTwo myListenerTwo;
    
        @Bean
        public ServletListenerRegistrationBean myFilterTwoConfig(){
            ServletListenerRegistrationBean<MyListenerTwo> servletListenerRegistrationBean = new ServletListenerRegistrationBean<>();
            servletListenerRegistrationBean.setListener(myListenerTwo);
            return servletListenerRegistrationBean;
        }
    
        @Bean
        public ServletListenerRegistrationBean myListenerConfig(){
            ServletListenerRegistrationBean<MyListener> servletListenerRegistrationBean = new ServletListenerRegistrationBean<>();
            servletListenerRegistrationBean.setListener(myListener);
            return servletListenerRegistrationBean;
        }
    }

**注：监听器配置类中对应监听器的配置对象的创建顺序就是执行顺序；**

**注：filter、listener、servlet都需要在启动类上加上注解@ServletComponentScan**

更多可参考([http://blog.csdn.net/king\_is\_everyone/article/details/53116744][http_blog.csdn.net_king_is_everyone_article_details_53116744])

[http_blog.csdn.net_king_is_everyone_article_details_53116744]: http://blog.csdn.net/king_is_everyone/article/details/53116744