SpringBoot项目logback不能打印日志问题解决

1、报错信息

Exception in thread "main" java.lang.NoClassDefFoundError: ch/qos/logback/core/util/StatusPrinter2
    at org.springframework.boot.logging.logback.LogbackLoggingSystem.<init>(LogbackLoggingSystem.java:113)
    at org.springframework.boot.logging.logback.LogbackLoggingSystem$Factory.getLoggingSystem(LogbackLoggingSystem.java:495)
    at org.springframework.boot.logging.DelegatingLoggingSystemFactory.getLoggingSystem(DelegatingLoggingSystemFactory.java:44)
    at org.springframework.boot.logging.LoggingSystem.get(LoggingSystem.java:167)
    at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationStartingEvent(LoggingApplicationListener.java:237)
    at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationEvent(LoggingApplicationListener.java:220)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:185)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:178)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:156)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:138)
    at org.springframework.boot.context.event.EventPublishingRunListener.multicastInitialEvent(EventPublishingRunListener.java:136)
    at org.springframework.boot.context.event.EventPublishingRunListener.starting(EventPublishingRunListener.java:75)
    at org.springframework.boot.SpringApplicationRunListeners.lambda$starting$0(SpringApplicationRunListeners.java:54)
    at java.base/java.lang.Iterable.forEach(Iterable.java:75)
    at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:118)
    at org.springframework.boot.SpringApplicationRunListeners.starting(SpringApplicationRunListeners.java:54)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:327)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1363)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1352)
    at com.moo.jsonmss.JsonMssApplication.main(JsonMssApplication.java:14)
Caused by: java.lang.ClassNotFoundException: ch.qos.logback.core.util.StatusPrinter2
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
    ... 20 more

2、分析

JDK21，pom.xml配置如下：

 <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>2.0.9</version>
        </dependency>

<!--         Logback 实现（Spring Boot 默认自带，通常不需要额外添加）-->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.4.11</version>
            <exclusions>
                <exclusion>
                    <artifactId>logback-core</artifactId>
                    <groupId>ch.qos.logback</groupId>
                </exclusion>
                <exclusion>
                    <artifactId>slf4j-api</artifactId>
                    <groupId>org.slf4j</groupId>
                </exclusion>
            </exclusions>
        </dependency>
<!--         Logback Core-->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>1.4.11</version> <!-- 使用合适版本 -->
        </dependency>

 logback.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{yyyy-MM-dd HH:mm:ss} %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <root level="info">
        <appender-ref ref="STDOUT" />
    </root>
</configuration>

检查配置无问题，排查包冲突，排除了logback-classic中的logback-core依赖，仍未解决；

继续查看jar包冲突，发现除了1.4.11版本的logback-classic，还存在1.51.8版本的，继续追查，原来，spring-boot-starter-logging中依赖logback-classic，版本是1.5.18；

最终解决：去除pom文件中，上述所有直接引入，包括slf4j-api、logback-classic、logback-core，完全依赖spring-boot-starter-logging中依赖的所有日志版本，完美解决；问题根源

3、问题根源

当项目中主动引入日志依赖时，一般根源还是jar包冲突；当前这个问题时，自行引入的和spring-boot-starter-logging依赖的日志版本不一致，导致报错；spring-boot-starter-logging下面已经提供所有slf具体日志实现，并确保版本一致，所以，不在需要自行引入；

4、推荐

idea排查解决jar包冲突，建议引入maven helper插件，如上述截图，非常便捷好用。