Request parameter log output sample Java & Spring MVC

Preface

I'm using Spring MVC ** I want to log the request URL and request parameters! ** ** That often happened, and each time I created a dedicated filter class,

Wouldn't it be happy if I left it in the article for myself?

I thought and described it. It's a completely personal note.

environment

• Java 8 (also works with 11)

• Spring Boot 2.2.1

• Spring MVC (version uses Boot rules)

• Lombok (version uses Boot rules)

• I have not tried it with Spring Web Flux.

Code sample

package com.example.demo.filter;

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

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Arrays;
import java.util.Map;

@Slf4j
@Component
public class LoggingFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest httpReq = ((HttpServletRequest)request);
        String uri = httpReq.getRequestURI();

        long start = System.currentTimeMillis();
        log.info(String.format("Start processing. URI: %s", uri));

        //Process the request parameter and output it as a one-line log
        Map<String, String[]> params = httpReq.getParameterMap();
        StringBuilder strParams = new StringBuilder("Request parameters: [");
        boolean isFirstParam = true;
        for (Map.Entry<String, String[]> param : params.entrySet()) {
            if (isFirstParam) {
                isFirstParam = false;
            } else {
                //Comma is added as a concatenator for the second and subsequent request parameters.
                strParams.append(", ");
            }
            strParams.append(param.getKey()).append("=").append(Arrays.toString(param.getValue()));
        }
        strParams.append("]");
        log.info(strParams.toString());

        //Implementation of each process
        chain.doFilter(request, response);

        int status = ((HttpServletResponse) response).getStatus();
        log.info(String.format("Processing Exit.Time required%d millis. STATUS=%d", System.currentTimeMillis() - start, status));
    }

    @Override
    public void destroy() {
    }
}

Log sample

2019-11-14 11:54:40.297  INFO 2001 --- [nio-8080-exec-1] com.example.demo.filter.LoggingFilter    :Start processing. URI: /demo/hello
2019-11-14 11:54:40.298  INFO 2001 --- [nio-8080-exec-1] com.example.demo.filter.LoggingFilter    :Request parameters: [hoge=[1], fuga=[2]]
2019-11-14 11:54:40.327  INFO 2001 --- [nio-8080-exec-1] com.example.demo.filter.LoggingFilter    :Processing Exit.Time required 30 millis. STATUS=200

Supplement

The log format remains the Spring Boot standard. Personally, the log output is written in Japanese because it is easy to understand in Japanese. Sometimes I think it's better to do this a little more, but I often write in this style. It's not surprising that the extended For statement is a bit disgusting, but it's annoying and hasn't been revised.

Note that this Filter supports array parameters, but does not support attachments.