Filter FILTER is part of the servlet container, part of the Servlet specification,
The interceptor is independent, which can be used in any case.

Filter filter

• There are two ways to implement filter
  1. Register via FilterRegistrationBean instance
  2. Take effect by @Webfilter (cannot set priority between filters)

FilterRegistrationBean method registration

1. Implement a Filter interface, write a filter

public class Test1Filter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    
    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        HttpServletRequest request=(HttpServletRequest)arg0;
        System.out.println("Custom filter Filter1 trigger, intercept URL:"+request.getRequestURI());
        arg2.doFilter(arg0,arg1);
    }
    
    @Override
    public void destroy() {
    }
}

2. Register the filter

FilterRegistrationBean instance registration filter

@Configuration
public class testFilterConfig {

    @Bean
    public FilterRegistrationBean<Test1Filter> RegistTest1(){
        
        FilterRegistrationBean<Test1Filter> bean = new FilterRegistrationBean<Test1Filter>();
        bean.setFilter(new Test1Filter());// Register a custom filter
        bean.setName("flilter1");// Filter name
        bean.addUrlPatterns("/*");// Filter all paths
        // Setting the priority via the FilterRegistrationBean instance can take effect through @Webfilter invalid
        bean.setOrder(1);// Priority, the top
        return bean;
    }
}

@Webfilter Note Registered Filter

Plus directly on Test1Filter class@WebFilter(urlPatterns = "/*", filterName = "Test1Filter1") Registration

1. @Webfilter This annotation is the specification of servlet3.0, not Spring Boot provided by Spring Boot.
2. @WebFilter This annotation does not specify the properties of the execution order, which depends on the name of the Filter, is based on the Filter class name (note that the name is not the configured filter) alphabetical alphabetical alphabetically
3. Filter priority is higher than FilterRegistrationBean configured filter

Interceptor interceptor

Implement the HandlerInterceptor interface, write interceptors

public class Test1CostInterceptor implements HandlerInterceptor {
    long start = System.currentTimeMillis();
    
    / / Request before execution
    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        System.out.println("Customized interceptor trigger, request start");
        return true;
    }
 
 	/ / Request end execution
    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("Custom interceptor trigger, request end");
    }
 
 	/ / After the view rendering is completed
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
    }
}

Registered interceptor

@Configuration
public class InterceptorConfig extends WebMvcConfigurerAdapter {
 
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new Test1CostInterceptor()).addPathPatterns("/**");
        super.addInterceptors(registry);
    }
}