过滤器、拦截器、ControllerAdvice和AOP

末蓝、 2024-03-22 13:04 48阅读 0赞

面试官：说说过滤器和拦截器的区别？ 这个问题面试题库算是比较经典的，这两个我相信很多同学在工作中都有接触过，但如果没有经过系统的整理，还真的不好说出个123来，那老湿机在此这面就把它俩和常用的AOP、ControllerAdvice放一起，带你做一个比较全面的认识。

### 1. 了解4种拦截方法的执行顺序 ###

先上一个栗子，看四种拦截方法并驾齐驱使用时，谁先谁后：

/**
     * ============Filter过滤器============
     */
    @Slf4j
    @WebFilter(urlPatterns = "/*")
    public class DemoFilter implements Filter {
        @Override
        public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
            log.info("Filter 进入");
            filterChain.doFilter(request, response);
            log.info("Filter 退出");
        }
    }
    l
    /**
     * ============Interceptor过滤器============
     */
    public class DemoInterceptor implements HandlerInterceptor {
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
            log.info("Interceptor preHandle 进入");
            return true;
        }
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
            log.info("Interceptor postHandle 进入");
        }
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
            log.info("Interceptor afterCompletion 进入");
        }
    }
    
    /**
     * ============ControllerAdvice============
     */
    @ControllerAdvice
    public class DemoControllerAdvice {
    
        @InitBinder
        public void init(WebDataBinder binder) {
            log.info("ControllerAdvice init 进入");
            binder.setFieldDefaultPrefix("user.");
        }
        @ExceptionHandler(Exception.class)
        public String handleException(Exception e) {
            log.info("ControllerAdvice handleException 进入");
            return "error";
        }
    }
    
    /**
     * ============AOP============
     */
    @Aspect
    @Component
    public class DemoAspect {
        @Pointcut("(@target(org.springframework.web.bind.annotation.RestController)) " +
                "&& within(cn.demo.api..*) && execution(public * *(..))")
        public void pointcut() {
        }
    
        @Around(value = "pointcut()")
        public Object around(ProceedingJoinPoint pjp) throws Throwable {
            log.info("Aop 进入");
            Object proceed = pjp.proceed();
            log.info(