时间：2022-12-20 10:12:18 | 栏目：JAVA代码 | 点击：次
前言:
在微服务环境中，我们经常使用Skywalking、CAT等去实现整体请求链路的追踪，但是这个整体运维成本高，架构复杂，我们来使用MDC通过Log来实现一个轻量级的会话事务跟踪功能。
MDC org.sl4j.MDC其实内部就是ThreadLocal，MDC提供了put/get/clear等几个核心接口，用于操作ThreadLocal中的数据；ThreadLocal中的K-V，可以在logback.xml中声明，最终将会打印在日志中。
// java代码
MDC.put("userId","laker");
// logback.xml
%X{userId}
例如：
<property name="pattern" value="%d{HH:mm:ss.SSS} [%thread] %-5level [%X{userId}] %logger{20} - %msg%n"/>
整体流程如下：
userId:laker。requestIdrequestId。userId和requestId去日志中捞请求链路。@Order(value = Ordered.HIGHEST_PRECEDENCE + 100)
@Component
@WebFilter(filterName = "MDCFilter", urlPatterns = "/*")
public class MDCFilter extends OncePerRequestFilter {
@Override
protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException {
try {
MDC.put("userId", "laker");
MDC.put("requestId", IdUtil.fastUUID());
} catch (Exception e) {
//
}
try {
filterChain.doFilter(httpServletRequest, httpServletResponse);
} finally {
MDC.clear();
}
}
}
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<property name="LOG_HOME" value="logs"/>
<property name="encoding" value="UTF-8"/>
<appender name="DEFAULT" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${LOG_HOME}/test.log</file>
<Append>true</Append>
<prudent>false</prudent>
<encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{50} %line - %m%n</pattern>
</encoder>
<!-- 按天回滚 daily -->
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<!--归档日志文件名-->
<FileNamePattern>${LOG_HOME}/test.log.%d{yyyy-MM-dd}</FileNamePattern>
<!-- 最多保存15天历史文件 -->
<maxHistory>15</maxHistory>
</rollingPolicy>
</appender>
<!-- 日志输出格式 -->
<property name="log.pattern"
value="%d{HH:mm:ss.SSS} [%thread] %-5level [%X{userId}|%X{requestId}] %logger{20} - [%method,%line] - %msg%n"/>
<!-- 控制台输出 -->
<appender name="console" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>${log.pattern}</pattern>
</encoder>
</appender>
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{50} %line - %m%n</pattern>
</encoder>
</appender>
<logger name="com.test.demo" level="DEBUG">
<appender-ref ref="DEFAULT"/>
</logger>
<!-- 日志输出级别 -->
<root level="INFO">
<appender-ref ref="DEFAULT"/>
<appender-ref ref="console"/>
</root>
</configuration>
public class Response<T> {
@ApiModelProperty(notes = "响应码，非200 即为异常", example = "200")
private final int code;
@ApiModelProperty(notes = "响应消息", example = "提交成功")
private final String msg;
@ApiModelProperty(notes = "响应数据")
private final T data;
@ApiModelProperty(notes = "请求id")
private final String requestId;
public Response(int code, String msg, T data) {
this.code = code;
this.msg = msg;
this.data = data;
this.requestId = MDC.get("requestId");
}
响应:
{
code: 200,
msg: "",
requestId: "74a269a8-3cb4-417e-853c-b968b77cce23"
}
日志:
18:37:15.997 [http-nio-8080-exec-1] INFO [laker|90717490-5ef4-4e46-bc2c-605952fc3803] c.l.m.c.InfoController - [v2Map,17] - null 18:37:38.980 [http-nio-8080-exec-2] INFO [laker|82bde351-f86e-466f-97a0-c857a0c4c1c9] c.l.m.c.InfoController - [v2Map,17] - null 18:37:39.992 [http-nio-8080-exec-3] INFO [laker|74a269a8-3cb4-417e-853c-b968b77cce23] c.l.m