springboot集成拦截器，过滤器，监听器 (拦截器和reids实现单设备登录)

客官°小女子只卖身不卖艺 2023-01-03 04:58 177阅读 0赞

## [springboot官方文档][springboot] ##

## [本项目地址][Link 1] ##

### 项目目录 ###

│ pom.xml
    └─src
        └─main
            ├─java
            │  └─com
            │      └─base
            │          │  Application.java # 启动类
            │          │
            │          ├─config
            │          │  │  WebMvcConfig.java mvc配置类，配置拦截器和资源策略
            │          │  │
            │          │  ├─filter # 过滤器
            │          │  │      MainFilter.java
            │          │  │
            │          │  ├─Interceptor # 拦截器
            │          │  │      Intercept.java
            │          │  │      OtherIntercept.java
            │          │  │
            │          │  └─listener # 监听器
            │          │          Listener.java
            │          │
            │          └─controller # 测试Controller
            │                  IndexController.java
            │
            └─resources 
                    application.yml # springboot配置

### Application.java 启动类代码 ###

package com.base;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.boot.CommandLineRunner;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.web.servlet.ServletComponentScan;
    
    /**
     * 开发公司：个人
     * 版权：个人
     * <p>
     * Application
     * @SpringBootApplication(scanBasePackages = {"com.base"})  scanBasePackages 扫描基础类包
     * @ServletComponentScan(basePackages = {"com.base"}) 扫描服务程序组件 （@WebServlet、@WebFilter、@WebListener等注解注解）
     * 启用@ServletComponentScan 注解后 Servlet、Filter、Listener可以直接通过@WebServlet、@WebFilter、@WebListener注解自动注册，无需其他代码。
      * @author 刘志强
     * @created Create Time: 2019/5/23
     */
    @SpringBootApplication(scanBasePackages = {"com.base"})
    @ServletComponentScan(basePackages = {"com.base"})
    public class Application  implements CommandLineRunner {
        private final Logger logger = LoggerFactory.getLogger(this.getClass());
    
        public static void main(String[] args) {
            SpringApplication.run(Application.class, args);
        }
    
        @Override
        public void run(String... strings) throws Exception {
            logger.info("程序启动");
        }
    }

用@ServletComponentScan注解后，Servlet、Filter、Listener可以直接通过@WebServlet、@WebFilter、@WebListener注解自动注册，无需其他代码。

### 拦截器 ###

拦截器应用场景

#### 1. 用拦截器控制单点登录 ####

##### 前后端不分离，使用session： #####

###### 登录 ######

登录时将用户信息存储至session中。
            session.setAttribute("usserId",user.getId());
    
    然后在将userId和sessionId 进行绑定存储至redis（也可以使用别的全局唯一数据源来存储，如静态Map,或别的缓存中间件）
            redisTemplate.opsForValue().set(user.getId(),session.getId());

##### 拦截器判断是否在别处登录 #####

拦截器从session中取出userId
         Long userId = (Long)session.getAttribute("usserId");
        =》 能取到表示已登录。取不到表示未登录或session过期已下线
    然后在根据userId从redis中取出sessionId 根据redis中的sessionId
    和当前登录sessionId进行比较
         String sessionId = (String) redisTemplate.opsForValue().get(userId);
         if (sessionId === session.getId()) 
        =》 如果一致表示没有在别处登录，如果不一致表示用户已在别处登录(因为如果有另一人在别处登录相同userId的redis会覆盖掉)

#### 前后端分离: ####

###### 登录 ######

登录时将用户信息存储至redis中。
             redisTemplate.opsForValue().set(token,user.getId());
    然后在将userId和token 进行绑定存储至redis（也可以使用别的全局唯一数据源来存储，如静态Map,或别的缓存中间件）
            redisTemplate.opsForValue().set(user.getId(),token);

##### 拦截器判断是否在别处登录 #####

拦截器从redis中根据token取出userId
         Long userId = (Long)redisTemplate.opsForValue().get(token);
        =》 能取到表示已登录。取不到表示未登录或token过期已下线
    然后在根据userId从redis中取出token 根据redis中的token
    和当前登录token进行比较
         String redisToken = (String) redisTemplate.opsForValue().get(userId);
         if (redisToken === token) 
        =》 如果一致表示没有在别处登录，如果不一致表示用户已在别处登录(因为如果有另一人在别处登录相同userId的redis会覆盖掉)

### Intercept.java ###

package com.base.config.Interceptor;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Component;
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /**
     * 拦截器
     */
    @Component
    public class Intercept implements HandlerInterceptor {
    
        protected Logger logger = LoggerFactory.getLogger(getClass());
    
        @Override
        public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
            logger.info("Controller方法调用前，被调用");
            return true;
        }
    
    
        @Override
        public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
            logger.info("请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后)");
        }
    
        @Override
        public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
            logger.info("在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）");
        }
    
    }

@Component 创建实例

### WebMvcConfig.java 将拦截器实例注册 ###

package com.base.config;
    
    import com.base.config.Interceptor.Intercept;
    import com.base.config.Interceptor.OtherIntercept;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
    
    /**
     * 开发公司：个人
     * 版权：刘志强
     * <p>
     * WebMvcConfig
     *
     * @author 刘志强
     * @created Create Time: 2019/2/16
     */
    @Configuration
    public class WebMvcConfig extends WebMvcConfigurerAdapter {
        @Autowired
        public Intercept intercept;
        @Autowired
        public OtherIntercept otherIntercept;
        //添加资源处理程序，resources资源目录下的static目录下的资源可以被直接访问
        @Override
        public void addResourceHandlers(ResourceHandlerRegistry registry) {
            registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");
        }
    
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
            /**
             * 多个拦截器组成一个拦截器链
             * addPathPatterns 用于添加拦截规则
             * excludePathPatterns 用于排除拦截
             */
            registry.addInterceptor(intercept)
                    .addPathPatterns("/**")
                    .excludePathPatterns("/index");
    
            registry.addInterceptor(otherIntercept)
                    .addPathPatterns("/**");
    
            super.addInterceptors(registry);
        }
    }

### 过滤器 ###

#### MainFilter.java ####

package com.base.config.filter;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    import javax.servlet.*;
    import javax.servlet.FilterConfig;
    import javax.servlet.annotation.WebFilter;
    import java.io.IOException;
    
    /**
     * 开发公司：个人
     * 版权：个人
     * <p>
     * MainFilter
     * @WebFilter(filterName = "mainFilter", urlPatterns = {"/*"})
     * filterName 过滤器名称 urlPatterns 需要过滤的url
     * @author 刘志强
     * @created Create Time: 2019/5/25
     */
    
    @WebFilter(filterName = "mainFilter", urlPatterns = {"/*"})
    public class MainFilter implements Filter {
    
        protected Logger logger = LoggerFactory.getLogger(getClass());
    
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
            logger.info("过滤器创建");
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
            logger.info("执行过滤请求");
            filterChain.doFilter(servletRequest, servletResponse);
        }
    
        @Override
        public void destroy() {
            logger.info("过滤器销毁");
        }
    }

init() 服务器启动时执行，初始化过滤器  
doFilter() 对urlPatterns声明请求进行过滤时执行

### 监听器 ###

#### Listener.java ####

package com.base.config.listener;
    
            import org.slf4j.Logger;
            import org.slf4j.LoggerFactory;
    
            import javax.servlet.ServletContextEvent;
            import javax.servlet.ServletContextListener;
            import javax.servlet.ServletRequestEvent;
            import javax.servlet.ServletRequestListener;
            import javax.servlet.annotation.WebListener;
            import javax.servlet.http.HttpSessionEvent;
            import javax.servlet.http.HttpSessionListener;
    
    /**
     * 开发公司：个人
     * 版权：个人
     * <p>
     * Listener
     *
     * @author 刘志强
     * @created Create Time: 2019/5/25
     */
    
    @WebListener()
    public class Listener implements ServletRequestListener, HttpSessionListener,ServletContextListener  {
    
        protected Logger logger = LoggerFactory.getLogger(getClass());
        // ServletRequestListener start
        @Override
        public void requestDestroyed(ServletRequestEvent servletRequestEvent) {
            logger.info("监听器到" + servletRequestEvent.getServletRequest().getServerName() + "被销毁");
        }
    
        @Override
        public void requestInitialized(ServletRequestEvent servletRequestEvent) {
            logger.info("监听器到" + servletRequestEvent.getServletRequest().getServerName() + "被创建");
        }
        // ServletRequestListener end
    
        // HttpSessionListener start
        @Override
        public void sessionCreated(HttpSessionEvent httpSessionEvent) {
            logger.info("监听器到" + httpSessionEvent.getSession().getId() + "被创建");
        }
    
        @Override
        public void sessionDestroyed(HttpSessionEvent httpSessionEvent) {
            logger.info("监听器到" + httpSessionEvent.getSession().getId() + "被销毁");
        }
        // HttpSessionListener end
    
        // ServletContextListener start
        @Override
        public void contextInitialized(ServletContextEvent servletContextEvent) {
            logger.info("监听器到" + servletContextEvent.getServletContext().getServerInfo() + "被创建");
        }
    
        @Override
        public void contextDestroyed(ServletContextEvent servletContextEvent) {
            logger.info("监听器到" + servletContextEvent.getServletContext().getContextPath() + "被销毁");
        }
        // ServletContextListener end
    
    
    }

[springboot]: http://spring.io/projects/spring-boot
[Link 1]: https://gitee.com/springbook_foundation/springboot-base-five