打印http request body 和 response body 以及请求日志跟踪

1、request 的inputStream和response 的outputStream默认情况下是只能读一次， 不可重复读；
这就导致要获取请求体或者响应体信息时必须要声明包裹类wrapper; spring为此提供了两个对应的包裹类
ContentCachingRequestWrapper和ContentCachingResponseWrapper使得这两个流信息可重复读;

因此可以利用这两个类读取请求和响应信息，输出到日志

import lombok.extern.slf4j.Slf4j;
import org.slf4j.MDC;
import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;
import org.springframework.web.util.ContentCachingRequestWrapper;
import org.springframework.web.util.ContentCachingResponseWrapper;
import org.springframework.web.util.WebUtils;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Enumeration;
import java.util.UUID;

/**
 * @Author: xxx
 * @Description:
 * @Date: created in 13:46 2018/7/7
 */
@Component
@Slf4j
public class WebLogFilter extends OncePerRequestFilter implements Ordered {

    // put filter at the end of all other filters to make sure we are processing after all others
    private int order = Ordered.LOWEST_PRECEDENCE - 8;

    public static final String SPLIT_STRING_M = "=";

    public static final String SPLIT_STRING_DOT = ", ";

    @Override
    public int getOrder() {
        return order;
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        //日志trade
        MDC.clear();
        MDC.put("trade_id", UUID.randomUUID().toString().replaceAll("-",""));
        ContentCachingRequestWrapper wrapperRequest = new ContentCachingRequestWrapper(request);
        ContentCachingResponseWrapper wrapperResponse = new ContentCachingResponseWrapper(response);
        String urlParams = getRequestParams(request);
        filterChain.doFilter(wrapperRequest, wrapperResponse);

        String requestBodyStr = getRequestBody(wrapperRequest);
        log.info("params[{}]|body:{}", urlParams, requestBodyStr);

        String responseBodyStr = getResponseBody(wrapperResponse);

        log.info("resp body:{}", responseBodyStr);
        wrapperResponse.copyBodyToResponse();
    }

    /**
     * 打印请求参数
     * @param request
     */
    private String getRequestBody(ContentCachingRequestWrapper request) {
        ContentCachingRequestWrapper wrapper = WebUtils.getNativeRequest(request, ContentCachingRequestWrapper.class);
        if(wrapper != null) {
            byte[] buf = wrapper.getContentAsByteArray();
            if(buf.length > 0) {
                String payload;
                try {
                    payload = new String(buf, 0, buf.length, wrapper.getCharacterEncoding());
                } catch (UnsupportedEncodingException e) {
                    payload = "[unknown]";
                }
                return payload.replaceAll("\\n","");
            }
        }
        return "";
    }

    /**
     * 打印请求参数
     * @param response
     */
    private String getResponseBody(ContentCachingResponseWrapper response) {
        ContentCachingResponseWrapper wrapper = WebUtils.getNativeResponse(response, ContentCachingResponseWrapper.class);
        if(wrapper != null) {
            byte[] buf = wrapper.getContentAsByteArray();
            if(buf.length > 0) {
                String payload;
                try {
                    payload = new String(buf, 0, buf.length, wrapper.getCharacterEncoding());
                } catch (UnsupportedEncodingException e) {
                    payload = "[unknown]";
                }
                return payload;
            }
        }
        return "";
    }

    /**
     * 获取请求地址上的参数
     * @param request
     * @return
     */
    public static String getRequestParams(HttpServletRequest request) {
        StringBuilder sb = new StringBuilder();
        Enumeration<String> enu = request.getParameterNames();
        //获取请求参数
        while (enu.hasMoreElements()) {
            String name = enu.nextElement();
            sb.append(name + SPLIT_STRING_M).append(request.getParameter(name));
            if(enu.hasMoreElements()) {
                sb.append(SPLIT_STRING_DOT);
            }
        }
        return sb.toString();
    }
}

2、利用slf4j的MDC跟踪请求信息, 打印完整的请求处理日志；主要代码如下

        //日志trade
        MDC.clear();
        //给本次请求分配一个唯一的tradeId
        MDC.put("trade_id", UUID.randomUUID().toString().replaceAll("-",""));

并在日志配置文件里加上trade_id的信息，如下

[%X{trade_id}]%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n

到此完成日志跟踪功能， 效果如下

[16fbd9304e23492cab3ccabb6a85d0c0]2018-07-07 16:18:49.130  INFO 13712 --- [nio-8188-exec-1] ren.xx.xx.filter.WebLogFilter       : params[ggii=44]|body:{    "account":"xxxxx",  "v_code":"056036"}
[16fbd9304e23492cab3ccabb6a85d0c0]2018-07-07 16:18:49.131  INFO 13712 --- [nio-8188-exec-1] ren.xx.xx.filter.WebLogFilter       : resp body:{"code":1,"msg":"请输入正确的验证码","data":"","success":false}