现象

SpringBoot项目，启动后，日志文件没有出现在logback-spring.xml指定的目录下，且启动日志开头如下：

"C:\Program Files\Java\jdk1.8.0_144\bin\java"...
Connected to the target VM, address: '127.0.0.1:52494', transport: 'socket'
18:34:58,011 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Could NOT find resource [logback-test.xml]
18:34:58,011 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Could NOT find resource [logback.groovy]
18:34:58,011 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Found resource [logback.xml] at [jar:file:/D:/mvn_repo/xxx-1.0.2.jar!/logback.xml]
18:34:58,014 |-INFO in ch.qos.logback.core.joran.spi.ConfigurationWatchList@707194ba - URL [jar:file:/D:/mvn_repo/yyy-1.0.2.jar!/logback.xml] is not of type file
18:34:58,112 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - Will scan for changes in [jar:file:/D:/mvn_repo/zzz-1.0.2.jar!/logback.xml] 

logback-spring.xml文件一直未改动过，如下：

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO">

    <springProperty scope="context" name="logPath" source="log.path"/>
    <springProperty scope="context" name="logLevel" source="log.level"/>


    <appender name="consoleLog" class="ch.qos.logback.core.ConsoleAppender">
        <layout class="ch.qos.logback.classic.PatternLayout">
            <pattern> %d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{36} %line - %msg%n</pattern>
        </layout>
    </appender>

    <appender name="fileLog" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <!--滚动策略-->
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!--输出路径-->
            <fileNamePattern>${logPath}/server.%d.log</fileNamePattern>
        </rollingPolicy>
        <encoder>
            <pattern> %d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{36} %line - %msg%n</pattern>
            <charset>UTF-8</charset>
        </encoder>
    </appender>

    <appender name="fileErrorLog" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>ERROR</level>
            <onMatch>ACCEPT</onMatch>
            <onMismatch>DENY</onMismatch>
        </filter>
        <!--滚动策略-->
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!--输出路径-->
            <fileNamePattern>${logPath}/server.%d.error</fileNamePattern>
        </rollingPolicy>
        <encoder>
            <pattern> %d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{36} %line - %msg%n</pattern>
            <charset>UTF-8</charset>
        </encoder>
    </appender>

    <root level="${logLevel}">
        <appender-ref ref="consoleLog"/>
        <appender-ref ref="fileLog"/>
        <appender-ref ref="fileErrorLog"/>
    </root>
</Configuration>

原因分析

1. 配置文件位置正确

classes/
├── application.properties
├── com
│   └── nero
│       └── test
│           ├── api
│           │   ├── Api.class

2. 分析启动日志，分析可能是依赖的jar中有logback.xml配置，冲突导致的问题

解决方案

在application.properties中加入配置：

logging.config=classpath:logback-spring.xml

通过该配置，强制指定日志的配置文件，问题得以解决

参考

Spring 默认日志logback配置解析