[Spring Interceptor] Introduction to Spring MVC HandlerInterceptor

https://www.baeldung.com/spring-mvc-handlerinterceptor

 

 

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* spring-web 종속

 

 

Spring MVC Handler

HandlerMapping은 handler method를 URL에 매핑한다

DispatcherServlet request 처리 시 호출할 수 있다

the DispatcherServlet uses the HandlerAdapter to actually invoke the method.

 

 

 

Spring Handler Interceptor

a Spring interceptor is a class that either extends the HandlerInterceptorAdapter class or implements the HandlerInterceptor interface.

The HandlerInterceptor contains three main methods:

• prehandle() – called before the execution of the actual handler
• postHandle() – called after the handler is executed
• afterCompletion() – called after the complete request is finished and the view is generated

These three methods provide flexibility to do all kinds of pre- and post-processing.

 

 

 

예시

@Override
public boolean preHandle(
  HttpServletRequest request,
  HttpServletResponse response, 
  Object handler) throws Exception {
    // your code
    return true;
}

@Override
public void postHandle(
  HttpServletRequest request, 
  HttpServletResponse response,
  Object handler, 
  ModelAndView modelAndView) throws Exception {
    // your code
}

@Override
public void afterCompletion(
  HttpServletRequest request, 
  HttpServletResponse response,
  Object handler, Exception ex) {
    // your code
}

https://docs.spring.io/spring-framework/docs/4.3.7.RELEASE_to_4.3.8.RELEASE/Spring%20Framework%204.3.8.RELEASE/org/springframework/web/servlet/mvc/annotation/DefaultAnnotationHandlerMapping.html

DefaultAnnotationHandlerMapping

 

 

 

interceptor custom 파일 리스트

 

예제코드의 인터셉터 디렉토리 리스트

 

 

 

public class LoggerInterceptor implements HandlerInterceptor {

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

    /**
     * Executed before actual handler is executed
     **/
    @Override
    public boolean preHandle(final HttpServletRequest request, final HttpServletResponse response, final Object handler) throws Exception {
        log.info("[preHandle][" + request + "]" + "[" + request.getMethod() + "]" + request.getRequestURI() + getParameters(request));
        return true;
    }

    /**
     * Executed before after handler is executed
     **/
    @Override
    public void postHandle(final HttpServletRequest request, final HttpServletResponse response, final Object handler, final ModelAndView modelAndView) throws Exception {
        log.info("[postHandle][" + request + "]");
    }

    /**
     * Executed after complete request is finished
     **/
    @Override
    public void afterCompletion(final HttpServletRequest request, final HttpServletResponse response, final Object handler, final Exception ex) throws Exception {
        if (ex != null)
            ex.printStackTrace();
        log.info("[afterCompletion][" + request + "][exception: " + ex + "]");
    }

    private String getParameters(final HttpServletRequest request) {
        final StringBuffer posted = new StringBuffer();
        final Enumeration<?> e = request.getParameterNames();
        if (e != null)
            posted.append("?");
        while (e != null && e.hasMoreElements()) {
            if (posted.length() > 1)
                posted.append("&");
            final String curr = (String) e.nextElement();
            posted.append(curr)
                .append("=");
            if (curr.contains("password") || curr.contains("answer") || curr.contains("pwd")) {
                posted.append("*****");
            } else {
                posted.append(request.getParameter(curr));
            }
        }

        final String ip = request.getHeader("X-FORWARDED-FOR");
        final String ipAddr = (ip == null) ? getRemoteAddr(request) : ip;
        if (!Strings.isNullOrEmpty(ipAddr))
            posted.append("&_psip=" + ipAddr);
        return posted.toString();
    }

    private String getRemoteAddr(final HttpServletRequest request) {
        final String ipFromHeader = request.getHeader("X-FORWARDED-FOR");
        if (ipFromHeader != null && ipFromHeader.length() > 0) {
            log.debug("ip from proxy - X-FORWARDED-FOR : " + ipFromHeader);
            return ipFromHeader;
        }
        return request.getRemoteAddr();
    }
}

 

 

해당 인터셉터 선언

@EnableWebMvc
@Configuration
@ComponentScan("com.baeldung.web.controller")
public class MvcConfig implements WebMvcConfigurer {

    public MvcConfig() {
        super();
    }

    // API

    @Override
    public void addViewControllers(final ViewControllerRegistry registry) {
        registry.addViewController("/anonymous.html");

        registry.addViewController("/login.html");
        registry.addViewController("/homepage.html");
        registry.addViewController("/console.html");
        registry.addViewController("/csrfHome.html");
    }

    @Bean
    public ViewResolver viewResolver() {
        final InternalResourceViewResolver bean = new InternalResourceViewResolver();

        bean.setViewClass(JstlView.class);
        bean.setPrefix("/WEB-INF/view/");
        bean.setSuffix(".jsp");

        return bean;
    }

    @Override
    public void addInterceptors(final InterceptorRegistry registry) {
        registry.addInterceptor(new LoggerInterceptor()); // 요기
        registry.addInterceptor(new UserInterceptor());
        registry.addInterceptor(new SessionTimerInterceptor());
    }
}