filter와 intercepter

프로그램을 동작시킬 때
프로그램 동작 이전, 중, 후 어떤 일이 일어나는지 체크가 필요하다.
이를 처리해주는 것이 filter와 intercepter!!

config/WebConfig.java

package WebSample.demo.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import javax.servlet.Filter;

@Slf4j
@Configuration
public class WebConfig implements WebMvcConfigurer {
    @Bean
    public FilterRegistrationBean loggingFilter() {
        FilterRegistrationBean<Filter> filterFilterRegistrationBean = new FilterRegistrationBean<>();
        filterFilterRegistrationBean.setFilter(new LogFilter());
        filterFilterRegistrationBean.setOrder(1);
        filterFilterRegistrationBean.addUrlPatterns("/*");

        return filterFilterRegistrationBean;
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LogIntercepter())
                .order(1)
                .addPathPatterns("/**")
                .excludePathPatterns("/css/*", "/images/*");

    }
}

config/LogIntercepter

package WebSample.demo.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Slf4j
public class LogIntercepter implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        log.info("preHandle LogIntercepter : " + Thread.currentThread());
        log.info("preHandle handler : " + handler);
        return HandlerInterceptor.super.preHandle(request, response, handler);
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        log.info("postHandle LogIntercepter : " + Thread.currentThread());
        log.info("postHandle handler : " + handler);
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        log.info("afterCompletion LogIntercepter : " + Thread.currentThread());
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

config/Logfilter

package WebSample.demo.config;


import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.servlet.*;
import java.io.IOException;

@Slf4j
public class LogFilter implements Filter {
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        //외부 -> filter (-> 처리 ->) filter -> 외부
        //chain.doFilter를 통해서 다음 filter 로직을 실행하도록 해준다.

        log.info("hello LogFilter : " + Thread.currentThread());
        chain.doFilter(request, response);
        log.info("goodbye LogFilter : " + Thread.currentThread());
    }
}

실행결과