springboot 过滤器、拦截器、切片（aspect）

　　本文的环境基础：springboot web模块，aop模块，rest风格

　　本文的测试功能：对UserController进行拦截，输出每个方法执行的耗时

• spring boot过滤器：过滤器只能取到request，response等信息，不能获取正在过滤的类的信息和方法的信息，不能获取请求参数

　　　过滤器的实现有两种方式：

• • 通过@Component注解，直接将filter交给spring管理，但是这种方式时过滤所有请求，我没有找到配置过滤路径的地方，欢迎朋友多多指教

@Component
public class TimeFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("TimeFilter : init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("TimeFilter : doFilter start");

        Long startTime = System.currentTimeMillis();

        filterChain.doFilter(servletRequest, servletResponse);

        System.out.println("TimeFilter : 执行耗时 -> " + (System.currentTimeMillis() - startTime) + "ms");

        System.out.println("TimeFilter : doFilter finish");
    }

    @Override
    public void destroy() {
        System.out.println("TimeFilter : destroy");
    }
}

　　　　　　这是过滤器的日志打印，controller千篇一律，这里就不在赘述。

• • 通过配置类的形式，这种方式可以配置路径

　　　　　　这里对上边的TimeFilter稍作修改，去掉@Component，然后在spring boot的带有@SpringBootApplication注解的主类的目录下级编写自定义WebConfig

@Configuration
public class WebConfig {

    @Bean
    public FilterRegistrationBean timeFilter() {
        FilterRegistrationBean bean = new FilterRegistrationBean();

        bean.setFilter(new TimeFilter());

        List<String> urls = new ArrayList<>();
        urls.add("/user/*");
        bean.setUrlPatterns(urls);

        return bean;
    }

}

           启动测试，效果类同，只不过多了一个URL的判断

• spring boot拦截器：拦截器可以在过滤器的基础上，可以获取类的信息和方法的信息，但是不能获得请求参数
  • 定义拦截器，注意：需要@Component，交给Spring管理

    @Component
    public class TimeInterceptor implements HandlerInterceptor {
        @Override
        public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
            System.out.println("TimeInterceptor : preHandle");
    
            httpServletRequest.setAttribute("startTime", System.currentTimeMillis());
    
            return true;
        }
    
        @Override
        public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object obj, ModelAndView modelAndView) throws Exception {
            System.out.println("TimeInterceptor : postHandle start");
    
            Long startTime = (Long) httpServletRequest.getAttribute("startTime");
            System.out.println("TimeInterceptor : 执行耗时 -> " + (System.currentTimeMillis() - startTime) + "ms");
    
            System.out.println("TimeInterceptor : 拦截类名 -> " + ((HandlerMethod) obj).getBean().getClass().getName());
            System.out.println("TimeInterceptor : 拦截方法名 -> " + ((HandlerMethod) obj).getMethod().getName());
    
            System.out.println("TimeInterceptor : postHandle finish");
        }
    
        @Override
        public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
            System.out.println("TimeInterceptor : afterCompletion");
            Long startTime = (Long) httpServletRequest.getAttribute("startTime");
            System.out.println("TimeInterceptor : 执行耗时 -> " + (System.currentTimeMillis() - startTime) + "ms");
            System.out.println("TimeInterceptor : exception -> " + e);31     }
    }

     

  • 配置类修改，这是在过滤器的基础上修改的

    @Configuration
    public class WebConfig extends WebMvcConfigurerAdapter {
    
        @Autowired
        private TimeInterceptor timeInterceptor;
    
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
            registry.addInterceptor(timeInterceptor);
        }
    
        @Bean
        public FilterRegistrationBean timeFilter() {
            FilterRegistrationBean bean = new FilterRegistrationBean();
    
            bean.setFilter(new TimeFilter());
    
            List<String> urls = new ArrayList<>();
            urls.add("/user/*");
            bean.setUrlPatterns(urls);
    
            return bean;
        }
    
    }

  • 测试结果，结论：首先进入filter --> 之后进入interceptor的preHandler --> 之后进入controller执行 --> interceptor postHandle --> interceptor afterCompletion --> filter，执行完毕

　　　　　　　当无异常抛出时，postHandle 和afterCompletion都会执行，当有异常抛出时，postHandle 不会执行，但是afterCompletion仍会执行，我们可以在这里对异常进行处理

　　　　

• spring boot aspect：切点在过滤器和拦截器的基础上，还可以获取请求参数
  • 定义切点，关于切点的定义，可以参考  https://docs.spring.io/spring/docs/4.3.14.RELEASE/spring-framework-reference/htmlsingle/#aop-pointcuts

    @Component
    @Aspect
    public class TimeAspect {
    
        @Around("execution(* com.mright.platform.controller.UserController.*(..))")
        public Object handleControllerMethod(ProceedingJoinPoint point) throws Throwable {
            System.out.println("TimeAspect : start");
            Long startTime = System.currentTimeMillis();
    
            Object[] args = point.getArgs();
            Arrays.stream(args).forEach(arg -> {
                System.out.println("TimeAspect : 参数 -> " + arg);
            });
    
            Object object = point.proceed();
    
            System.out.println("TimeAspect : finish");
    
            System.out.println("TimeAspect : 执行耗时 -> " + (System.currentTimeMillis() - startTime) + "ms");
            return object;
        }
    
    }

     

  • 运行结果如下，执行顺序显而易见，filter --> interceptor --> aspect