平时写项目的时候，java之父叫我们多打日志，我们通常使用traceId和requestId来保存完整请求的链路日志，例如市面上的skywalking、zipkin等都能实现此功能。
下面介绍一种slf4j自带的MDC类，来记录完整的请求日志，和在CompletableFuture异步线程中如何保留链路id
1.首先利用aop为所有请求入口添加requestId。
@Aspect
@Component
public class LoggingAspect {
@Around("@annotation(org.springframework.web.bind.annotation.GetMapping) || " +
"@annotation(org.springframework.web.bind.annotation.PostMapping) || " +
"@annotation(org.springframework.web.bind.annotation.PutMapping) || " +
"@annotation(org.springframework.web.bind.annotation.DeleteMapping)")
public Object logAround(ProceedingJoinPoint joinPoint) throws Throwable {
// 在logback-spring.xml里对应%X{requestId}
MDC.put("requestId", UUID.randomUUID().toString().substring(0, 13)); // Add request ID to MDC
try {
return joinPoint.proceed(); // Execute method
} finally {
MDC.remove("requestId"); // Remove request ID from MDC
}
}
}2.定义一下 logback-spring.xml ，引入 requestId 来进行链路记录，关键代码是 %X{requestId}
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<!-- 控制台日志格式 -->
<property name="CONSOLE_LOG_PATTERN" value="${CONSOLE_LOG_PATTERN:-%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){faint} %X{requestId} %clr(${LOG_LEVEL_PATTERN:-%5p}) %clr(${PID:- }){magenta} %clr(---){faint} %clr([%15.15t]){faint} %clr(%-40.40logger{39}){cyan} %clr(:){faint} %m%n${LOG_EXCEPTION_CONVERSION_WORD:-%wEx}}"/>
<!-- 控制台日志格式 依赖的渲染类 -->
<conversionRule conversionWord="clr" converterClass="org.springframework.boot.logging.logback.ColorConverter" />
<conversionRule conversionWord="wex" converterClass="org.springframework.boot.logging.logback.WhitespaceThrowableProxyConverter" />
<conversionRule conversionWord="wEx" converterClass="org.springframework.boot.logging.logback.ExtendedWhitespaceThrowableProxyConverter" />
<!-- 输出到控制台 -->
<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<filter class="ch.qos.logback.classic.filter.ThresholdFilter">
<level>debug</level>
</filter>
<!-- 配置日志输出格式 -->
<pattern>${CONSOLE_LOG_PATTERN}</pattern>
<!-- 使用的字符集 -->
<charset>UTF-8</charset>
</encoder>
</appender>
<!-- 定义输出的路径，获取application.yml的source的值 -->
<springProperty scope="context" name="LOG_FILE_PATH" source="logging.file-location" default="/var/log/myapp"/>
<!-- 2.输出到文件 -->
<!-- 2.1 level为 DEBUG 日志，时间滚动输出 -->
<appender name="DEBUG_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${LOG_FILE_PATH}/debug.log</file> <!-- 文件路径 -->
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} %X{requestId} [%thread] %-5level %logger{50} - %msg%n</pattern><!-- 日志文档输出格式 -->
<charset>UTF-8</charset>
</encoder>
<!-- 日志记录器的滚动策略，按日期，按大小记录 -->
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<!-- 每天新开一个文件 -->
<fileNamePattern>${LOG_FILE_PATH}/debug-%d{yyyy-MM-dd}.%i.log</fileNamePattern>
<!-- 每天100m新开一个文件 -->
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>100MB</maxFileSize>
</timeBasedFileNamingAndTriggeringPolicy>
<!-- 日志文档保留天数 -->
<maxHistory>15</maxHistory>
<!-- 用来指定日志文件的上限大小，例如设置为1GB的话，那么到了这个值，就会删除旧的日志。 -->
<totalSizeCap>1GB</totalSizeCap>
</rollingPolicy>
<!-- 此日志文档只记录debug级别的 -->
<filter class="ch.qos.logback.classic.filter.LevelFilter">
<level>debug</level>
<onMatch>ACCEPT</onMatch>
<onMismatch>DENY</onMismatch>
</filter>
</appender>
<!-- 2.2 level为 INFO 日志，时间滚动输出 -->
<appender name="INFO_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${LOG_FILE_PATH}/info.log</file>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} %X{requestId} [%thread] %-5level %logger{50} - %msg%n</pattern>
<charset>UTF-8</charset>
</encoder>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>${LOG_FILE_PATH}/info-%d{yyyy-MM-dd}.%i.log</fileNamePattern>
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>100MB</maxFileSize>
</timeBasedFileNamingAndTriggeringPolicy>
<maxHistory>15</maxHistory>
</rollingPolicy>
<!-- 此日志文档只记录info级别的 -->
<filter class="ch.qos.logback.classic.filter.LevelFilter">
<level>info</level>
<onMatch>ACCEPT</onMatch>
<onMismatch>DENY</onMismatch>
</filter>
</appender>
<!-- 2.3 level为 WARN 日志，时间滚动输出 -->
<appender name="WARN_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${LOG_FILE_PATH}/warn.log</file>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} %X{requestId} [%thread] %-5level %logger{50} - %msg%n</pattern>
<charset>UTF-8</charset> <!-- 此处设置字符集 -->
</encoder>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>${LOG_FILE_PATH}/warn-%d{yyyy-MM-dd}.%i.log</fileNamePattern>
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>100MB</maxFileSize>
</timeBasedFileNamingAndTriggeringPolicy>
<maxHistory>15</maxHistory>
</rollingPolicy>
<!-- 此日志文档只记录warn级别的 -->
<filter class="ch.qos.logback.classic.filter.LevelFilter">
<level>warn</level>
<onMatch>ACCEPT</onMatch>
<onMismatch>DENY</onMismatch>
</filter>
</appender>
<!-- 2.4 level为 ERROR 日志，时间滚动输出 -->
<appender name="ERROR_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${LOG_FILE_PATH}/error.log</file>
<!--日志文档输出格式-->
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} %X{requestId} [%thread] %-5level %logger{50} - %msg%n</pattern>
<charset>UTF-8</charset>
</encoder>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>${LOG_FILE_PATH}/error-%d{yyyy-MM-dd}.%i.log</fileNamePattern>
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>100MB</maxFileSize>
</timeBasedFileNamingAndTriggeringPolicy>
<maxHistory>15</maxHistory>
</rollingPolicy>
<!-- 此日志文档只记录ERROR级别的 -->
<filter class="ch.qos.logback.classic.filter.LevelFilter">
<level>ERROR</level>
<onMatch>ACCEPT</onMatch>
<onMismatch>DENY</onMismatch>
</filter>
</appender>
<!-- 使用异步，一个AsyncAppender只能添加一个appender-ref -->
<appender name="ASYNC_DEBUG_FILE" class="ch.qos.logback.classic.AsyncAppender">
<appender-ref ref="DEBUG_FILE"/>
</appender>
<appender name="ASYNC_INFO_FILE" class="ch.qos.logback.classic.AsyncAppender">
<appender-ref ref="INFO_FILE"/>
</appender>
<appender name="ASYNC_WARN_FILE" class="ch.qos.logback.classic.AsyncAppender">
<appender-ref ref="WARN_FILE"/>
</appender>
<appender name="ASYNC_ERROR_FILE" class="ch.qos.logback.classic.AsyncAppender">
<appender-ref ref="ERROR_FILE"/>
</appender>
<!-- 开启上面的appender -->
<root level="info">
<appender-ref ref="CONSOLE" />
<appender-ref ref="ASYNC_DEBUG_FILE" />
<appender-ref ref="ASYNC_INFO_FILE" />
<appender-ref ref="ASYNC_WARN_FILE" />
<appender-ref ref="ASYNC_ERROR_FILE" />
</root>
</configuration>2.定义一个`复杂`业务流程，来看看日志的实力
private final ExecutorService executorService = Executors.newFixedThreadPool(4);
@GetMapping("saveUser")
public String saveUser() {
log.info("进入了saveUser");
// 异步
CompletableFuture.runAsync(()-> b(), executorService);
log.info("退出了saveUser");
return "Ok";
}
private void b() {
log.info("进入了b");
}日志如下，可以看到异步线程的requestId丢失了，21dbaad3-3158 这个就是requestId，这种情况下我们需要自定义线程类来保存MDC的上下文
2023-04-19 11:51:59.309 21dbaad3-3158 INFO 23044 --- [p-nio-80-exec-1] c.h.m.api.CompletableFutureApi : 进入了saveUser
2023-04-19 11:51:59.312 21dbaad3-3158 INFO 23044 --- [p-nio-80-exec-1] c.h.m.api.CompletableFutureApi : 退出了saveUser
2023-04-19 11:51:59.312 INFO 23044 --- [pool-1-thread-1] c.h.m.api.CompletableFutureApi : 进入了b
3.定义线程实现类，并且在构造函数中存储MDC的上下文
public static class MdcTaskWrapper implements Runnable {
private final Runnable task;
private final Map<String, String> contextMap;
public MdcTaskWrapper(Runnable task) {
this.task = task;
this.contextMap = MDC.getCopyOfContextMap();
}
@Override
public void run() {
if (contextMap != null) {
MDC.setContextMap(contextMap);
}
try {
task.run();
} finally {
MDC.clear();
}
}
}4.接下来再改写一下runAsync的使用方式，我们用MdcTaskWrapper来进行线程操作，这个线程类是包含mdc上下文的
@GetMapping("saveUser")
public String saveUser() {
log.info("进入了saveUser");
// 异步
CompletableFuture.runAsync(this::b, command -> executorService.execute(new MdcTaskWrapper(command)));
log.info("退出了saveUser");
return "Ok";
}
private void b() {
log.info("进入了b");
}可以看到，requestId：4ab037ab-92cb，异步线程能够拿到MDC的上下文，并且成功记录链路日志
2023-04-19 11:58:27.581 4ab037ab-92cb INFO 6816 --- [p-nio-80-exec-5] c.h.m.api.CompletableFutureApi : 进入了saveUser
2023-04-19 11:58:27.582 4ab037ab-92cb INFO 6816 --- [p-nio-80-exec-5] c.h.m.api.CompletableFutureApi : 退出了saveUser
2023-04-19 11:58:27.582 4ab037ab-92cb INFO 6816 --- [pool-1-thread-1] c.h.m.api.CompletableFutureApi
以上就是详解Java如何在CompletableFuture中实现日志记录的详细内容，更多关于Java CompletableFuture日志记录的资料请关注编程网其它相关文章！
