这是一个建议而不是答案，但如果你在你的web应用程序中使用Spring MVC，最好使用Spring HandlerInterceptor而不是Filter。

它可以做同样的工作，但是

可以使用ModelAndView吗 它的方法可以在请求处理之前和之后调用，或者在请求完成之后调用。 它很容易测试

1. 实现HandlerInterceptor接口，并向类中添加@Component注释

@Component
public class SecurityInterceptor implements HandlerInterceptor {

    private static Logger log = LoggerFactory.getLogger(SecurityInterceptor.class);

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        request.getSession(true);
        if(isLoggedIn(request))
            return true;

        response.getWriter().write("{\"loggedIn\":false}");
        return false;
    }

    private boolean isLoggedIn(HttpServletRequest request) {
        try {
            UserSession userSession = (UserSession) request.getSession(true).getAttribute("userSession");
            return userSession != null && userSession.isLoggedIn();
        } catch(IllegalStateException ex) {
            return false;
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {

    }
}

2. 配置拦截器

@Configuration
public class WebConfig implements WebMvcConfigurer {

    private HandlerInterceptor securityInterceptor;

    @Autowired
    public void setSecurityInterceptor(HandlerInterceptor securityInterceptor) {
        this.securityInterceptor = securityInterceptor;
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(securityInterceptor).addPathPatterns("/**").excludePathPatterns("/login", "/logout");
    }

}

你可以在实现javax.servlet.Filter的类上使用@WebFilter javax.servlet.annotation.WebFilter:

@WebFilter(urlPatterns = "/*")
public class MyFilter implements Filter {
}

然后使用@ServletComponentScan注册。

使用Spring注册过滤器大约有四种不同的选项。

首先，我们可以创建一个实现Filter或扩展HttpFilter的Spring bean:

@Component
public class MyFilter extends HttpFilter {

    @Override
    protected void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) 
        throws IOException, ServletException {
        // Implementation details...

        chain.doFilter(request, response);
    }
}

其次，我们可以创建一个扩展GenericFilterBean的Spring bean:

@Component
public class MyFilter extends GenericFilterBean {

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain)
  throws IOException, ServletException {
    //Implementation details...

        chain.doFilter(currentRequest, servletResponse);
    }
}

我们也可以使用FilterRegistrationBean类:

@Configuration
public class FilterConfiguration {

    private final MyFilter myFilter;

    @Autowired
    public FilterConfiguration(MyFilter myFilter) {
        this.myFilter = myFilter;
    }

    @Bean
    public FilterRegistrationBean<MyFilter> myFilterRegistration() {
        FilterRegistrationBean<DateLoggingFilter> filterRegistrationBean = new FilterRegistrationBean<>();
        filterRegistrationBean.setFilter(myFilter);
        filterRegistrationBean.setUrlPatterns(Collections.singletonList("/*"));
        filterRegistrationBean.setDispatcherTypes(DispatcherType.REQUEST);
        filterRegistrationBean.setOrder(Ordered.LOWEST_PRECEDENCE - 1);
        return filterRegistrationBean;
    }
}

最后，我们可以使用@ServletComponentScan的@WebFilter注释:

@WebFilter(urlPatterns = "/*", dispatcherTypes = {DispatcherType.REQUEST})
public class MyFilter extends HttpFilter {

    @Override
    protected void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
  throws IOException, ServletException {
        // Implementation details...

        chain.doFilter(request, response);
    }
}

如果您使用Spring Boot + Spring Security，则可以在安全配置中执行此操作。

在下面的示例中，我在UsernamePasswordAuthenticationFilter之前添加了一个自定义过滤器(请参阅所有默认的Spring安全过滤器及其顺序)。

@EnableWebSecurity
class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired FilterDependency filterDependency;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .addFilterBefore(
                new MyFilter(filterDependency),
                UsernamePasswordAuthenticationFilter.class);
    }
}

还有筛选器类

class MyFilter extends OncePerRequestFilter  {
    private final FilterDependency filterDependency;

    public MyFilter(FilterDependency filterDependency) {
        this.filterDependency = filterDependency;
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request,
        HttpServletResponse response,
        FilterChain filterChain)
        throws ServletException, IOException {

        // Filter
        filterChain.doFilter(request, response);
    }
}

你也可以使用@WebFilter来创建一个过滤器。这样就行了。

@Configuration
public class AppInConfig
{
    @Bean
    @Order(1)
    public FilterRegistrationBean aiFilterRegistration()
    {
        FilterRegistrationBean registration = new FilterRegistrationBean();
        registration.setFilter(new TrackingFilter());
        registration.addUrlPatterns("/**");
        registration.setOrder(1);
        return registration;
    }

    @Bean(name = "TrackingFilter")
    public Filter TrackingFilter()
    {
        return new TrackingFilter();
    }
}

过滤器主要用于日志文件中。它根据您在项目中使用的记录器而有所不同。

让我解释一下log4j2:

<Filters>
    <!-- It prevents an error -->
    <ThresholdFilter level="error" onMatch="DENY" onMismatch="NEUTRAL"/>

    <!-- It prevents debug -->
    <ThresholdFilter level="debug" onMatch="DENY" onMismatch="NEUTRAL" />

    <!-- It allows all levels except debug/trace -->
    <ThresholdFilter level="info" onMatch="ACCEPT" onMismatch="DENY" />
</Filters>

过滤器用于限制数据，我使用阈值过滤器进一步限制流中的数据级别。我提到了可以限制的水平。

请参见“log4j2 - Log4J Levels”的级别顺序:ALL > TRACE > DEBUG > INFO > WARN > ERROR > FATAL > OFF