过滤器（Filter）与拦截器（）主要区别包括以下几个方面：

• Filter是依赖于Servlet容器，属于Servlet规范的一部分，而拦截器则是独立存在的，可以在任何情况下使用。

• Filter的执行由Servlet容器回调完成，而拦截器通常通过动态代理的方式来执行。

• Filter的生命周期由Servlet容器管理，而拦截器则可以通过IoC容器来管理，因此可以通过注入等方式来获取其他Bean的实例，使用更方便。

   

拦截器

1. 自定义拦截器

/**通过路径进行权限拦截*/@Componentpublic class PermissionInterceptor implements HandlerInterceptor {@Autowiredprivate RedisComponent redisComponent;//preHandle是在请求执行前执行的@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)throws Exception {String token = request.getRemoteUser();if (StringUtils.isEmpty(token)){throw new AuthorityException();}ShareManagerPO shareManagerPO = (ShareManagerPO)redisComponent.getValue(token, ShareManagerPO.class);String requestURI = request.getRequestURI();List<PermissionPO> permissionList = shareManagerPO.getPermissionList();ArrayList<String> urls = new ArrayList<>();for (PermissionPO permissionPO : permissionList) {urls.add(permissionPO.getPath());}int indexOf = requestURI.lastIndexOf("/");String substring = requestURI.substring(1,indexOf);if (urls.contains(substring)){return true;}else {throw new AuthorityException();}}@Overridepublic void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {}}

1. 拦截器的配置

```java@Configurationpublic class PermissionConfig implements WebMvcConfigurer {@AutowiredPermissionInterceptor permissionInterceptor;@Overridepublic void addInterceptors(InterceptorRegistry registry) {//指定拦截器，指定拦截路径registry.addInterceptor(permissionInterceptor).addPathPatterns("/**")//不被拦截的路径.excludePathPatterns("/shareManager/**").excludePathPatterns("/swagger-resources/**", "/webjars/**", "/v2/**", "/swagger-ui.html/**");}//配置不被拦截的静态资源@Overridepublic void addResourceHandlers(ResourceHandlerRegistry registry) {registry.addResourceHandler("/swagger-ui.html").addResourceLocations("classpath:/META-INF/resources/");registry.addResourceHandler("/webjars/**").addResourceLocations("classpath:/META-INF/resources/webjars/");}}```

过滤器

过滤器（Filter）是Servlet中常用的技术，可以实现用户在访问某个目标资源之前，对访问的请求和响应进行拦截，常用的场景有登录校验、权限控制、敏感词过滤

下面是springboot项目利用过滤器来获取登录成功用户的信息

GenericFilterBean 只需要在自定义类中重写doFilter方法

public class TokenAuthenticateFilter extends GenericFilterBean {private BaseTokenAuth service;
​public TokenAuthenticateFilter(BaseTokenAuth service) {this.service = service;}
​@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {Authentication authentication = service.getAuthentication((HttpServletRequest) request);//存放authentication到SecurityContextHolder   存储用户信息SecurityContextHolder.getContext().setAuthentication(authentication);filterChain.doFilter(request, response);}
}

一、@WebFilter注解方式

使用@WebFilter注解为声明当前类为filter，第一个参数为该filter起一个名字，第二个参数为说明要拦截的请求地址，当前类需要实现Filter接口，里面有三个方法，分别为过滤器初始化、过滤方法和过滤器销毁。

@Slf4j
@WebFilter(filterName = "myFilter1", urlPatterns = "/*")
public class MyFilter1 implements Filter {@Overridepublic void init(FilterConfig filterConfig) throws ServletException {log.info(filterConfig.getFilterName() + " init");}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) {log.info("myFilter1 begin");try {log.info("业务方法执行");chain.doFilter(request, response);} catch (Exception e) {log.error("error!", e);}log.info("myFilter1 end");}@Overridepublic void destroy() {}
}

启动类添加@ServletComponentScan注解，@ServletComponentScan注解所扫描的包路径必须包含该Filter，代码如下：

SpringBootApplication
@ServletComponentScan(basePackages = "com.example.demo.filter")
public class DemoApplication {public static void main(String[] args) {SpringApplication.run(DemoApplication.class, args);}
}

二、@Bean注解方式

@Slf4j
public class MyFilter2 implements Filter {@Overridepublic void init(FilterConfig filterConfig) throws ServletException {log.info(filterConfig.getFilterName() + " init");}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) {log.info("myFilter2 begin");try {log.info("业务方法执行");chain.doFilter(request, response);} catch (Exception e) {log.error("error!", e);}log.info("myFilter2 end");}@Overridepublic void destroy() {}
}

新建配置类WebConfig.java，配置bean，代码如下：

@Configuration
public class WebConfig {@Beanpublic FilterRegistrationBean testFilterRegistration() {FilterRegistrationBean registration = new FilterRegistrationBean(new MyFilter2());registration.addUrlPatterns("/test"); //registration.setName("myFilter2");return registration;}
}