如何优雅的打印项目日志

框架
springboot

原理

使用filter拦截请求，打印出请求、响应，及耗时

知识点
1、OncePerRequestFilter

Filter base class that aims to guarantee a single execution per request dispatch, on any servlet container.Filter base class that aims to guarantee a single execution per request dispatch, on any servlet container.
过滤器基类，旨在保证在任何 servlet 容器上每个请求调度一次执行。

兼容多种servlet版本，保证在任何 servlet 容器上每个请求调度一次执行。

2、ContentCachingRequestWrapper，ContentCachingResponseWrapper
HttpServletRequest 包装器，用于缓存从输入流和读取器读取的所有内容，并允许通过字节数组检索此内容。
源代码如下，第一次获取输入流时，复制了一份

因为request的数据流只能读取一次，通过过滤器读取一次后，后面的业务处理会读不到数据
通过ContentCachingRequestWrapper将请求包装，可以进行多次读取

实现

继承OncePerRequestFilter，重写doFilterInternal方法

日志打印Filter

import com.google.common.base.Throwables;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.MediaType;
import org.springframework.web.filter.OncePerRequestFilter;
import org.springframework.web.util.ContentCachingRequestWrapper;
import org.springframework.web.util.ContentCachingResponseWrapper;import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Enumeration;@Slf4j
public class LogFilter extends OncePerRequestFilter {private Integer printMaxSize;public LogFilter() {}public LogFilter(Integer printMaxSize) {if (printMaxSize == null) {printMaxSize = 1024;}this.printMaxSize = printMaxSize;}@Overrideprotected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException {if (isAsyncDispatch(httpServletRequest)) {filterChain.doFilter(httpServletRequest, httpServletResponse);} else {doLogFilter(getRequestWrapper(httpServletRequest), getResponseWrapper(httpServletResponse), filterChain);}}private void doLogFilter(ContentCachingRequestWrapper requestWrapper, ContentCachingResponseWrapper responseWrapper, FilterChain filterChain) throws IOException, ServletException {StringBuilder sb = new StringBuilder();sb.append(System.lineSeparator()).append("Method: [").append(requestWrapper.getMethod()).append("] ").append("URI: ").append(requestWrapper.getRequestURI()).append(System.lineSeparator());long start = System.currentTimeMillis();filterChain.doFilter(requestWrapper, responseWrapper);try {sb.append(getParams(requestWrapper)).append(System.lineSeparator());sb.append(getBody(requestWrapper));sb.append(getResponse(responseWrapper)).append(System.lineSeparator());} catch (Exception e) {log.warn("日志打印失败 e:{}", Throwables.getStackTraceAsString(e));} finally {responseWrapper.copyBodyToResponse();long end = System.currentTimeMillis();sb.append("use time :").append(end - start).append("ms");log.info(sb.toString());}}private String getBody(ContentCachingRequestWrapper requestWrapper) {StringBuilder sb = new StringBuilder();String contentType = requestWrapper.getContentType();if (requestWrapper.getMethod().equalsIgnoreCase("POST")&& (MediaType.APPLICATION_JSON_VALUE.equals(contentType)|| MediaType.APPLICATION_JSON_UTF8_VALUE.equals(contentType))) {sb.append("body: ").append(System.lineSeparator());sb.append(new String(requestWrapper.getContentAsByteArray(), StandardCharsets.UTF_8));sb.append(System.lineSeparator());}return sb.toString();}private String getResponse(ContentCachingResponseWrapper responseWrapper) {String responseStr = new String(responseWrapper.getContentAsByteArray(), StandardCharsets.UTF_8);responseStr = responseStr.length() > printMaxSize ? responseStr.substring(0, printMaxSize) : responseStr;return "response: " + responseStr;}private String getParams(ContentCachingRequestWrapper requestWrapper) {Enumeration<String> enumeration = requestWrapper.getParameterNames();StringBuilder sb = new StringBuilder();sb.append("params: ");while (enumeration.hasMoreElements()) {String paramName = enumeration.nextElement();sb.append(paramName);sb.append(" : ");sb.append(requestWrapper.getParameter(paramName));sb.append(", ");}if (sb.length() > 2) {sb.replace(sb.length() - 2, sb.length(), "");}return sb.toString();}private ContentCachingResponseWrapper getResponseWrapper(HttpServletResponse httpServletResponse) {if (httpServletResponse instanceof ContentCachingResponseWrapper) {return (ContentCachingResponseWrapper) httpServletResponse;} else {return new ContentCachingResponseWrapper(httpServletResponse);}}private ContentCachingRequestWrapper getRequestWrapper(HttpServletRequest httpServletRequest) {if (httpServletRequest instanceof ContentCachingRequestWrapper) {return (ContentCachingRequestWrapper) httpServletRequest;} else {return new ContentCachingRequestWrapper(httpServletRequest, printMaxSize);}}
}

注入容器

@Configuration
public class FilterConfig {/* 日志长度限制*/private Integer printMaxSize = 1024;@Beanpublic LogFilter getLogFilter() {return new LogFilter(printMaxSize);}}