Question

我正在为项目使用spring启动应用程序，并在使用java -jar build/libs/com.user.admin.rest.services.jar从jar运行项目时收到以下错误。但它不是一个拦截器，我能够访问api，并且记录器按预期工作正常。我只是想解决这个错误。

ERROR StatusLogger Unable to create class org.apache.logging.log4j.core.impl.Log4jContextFactory specified in jar:file:/Users/Samuel/UserMgmt/com.user.admin.rest.services/build/libs/com.user.admin.rest.services.jar!/META-INF/log4j-provider.properties
 java.lang.ClassNotFoundException: org.apache.logging.log4j.core.impl.Log4jContextFactory
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at org.apache.logging.log4j.spi.Provider.loadLoggerContextFactory(Provider.java:96)
    at org.apache.logging.log4j.LogManager.<clinit>(LogManager.java:91)
    at com.user.admin.rest.services.api.UserServiceResource.<clinit>(UserServiceResource.java:32)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:142)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:89)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1147)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1099)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542)
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:314)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151)
    at com.user.admin.rest.services.api.Application.main(Application.java:27)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
    at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)

我在build.gradle文件中为logger添加了以下行。

compile 'org.apache.logging.log4j:log4j-api:2.8.2' compile 'org.apache.logging.log4j:log4j-core:2.8.2'

我的log4j2.xml文件在下面给出

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xml>
<Configuration status="ERROR" name="example-config">
    <Properties>
        <Property name="PATTERN">%-5level %d [%t] %c:%M(%L): %m%n</Property>
    </Properties>
    <Appenders>
        <Console name="STDOUT" target="SYSTEM_OUT">
            <PatternLayout pattern="${PATTERN}" />
        </Console>
    </Appenders>
    <Loggers>
        <Root level="TRACE">
            <AppenderRef ref="STDOUT" />
        </Root>
    </Loggers>
</Configuration>

Answer 1

一般来说，您永远不需要切换日志记录实现; Logback应该适合你。但是，如果您决定使用Log4j或Log4j2，则需要更改依赖项以包含要使用的日志记录实现的相应启动器并排除Logback。 Spring Boot in Action

在Gradle中更换Log4j2的Logback

排除默认日志记录

configurations {
  all*.exclude group:'org.springframework.boot',
               module:'spring-boot-starter-logging'
}

添加Log4j2记录

compile("org.springframework.boot:spring-boot-starter-log4j2")

您可以找到Spring Boot here提供的 spring-boot-starter-log4j2 依赖版本的详细信息。

Answer 2

我遇到了类似的问题。 log4j-api和log4j-core的版本必须匹配（此处ClassNotFound是一个奇怪的例外）。正如您在评论中所说，您已找到log4j-core-2.7.jar，但我猜您的log4j-api版本为 2.8.2 ，如上图所示。

检查您的依赖项，删除旧版本的log4j-core并添加新版本以解决问题。

Answer 3

此异常打印到System.out，因为该类不在Spring的引导加载程序的类路径中。但这不是记录不工作或不使用指定配置文件的原因。

这是一个Spring Boot Gradle插件问题。它应该在检测到对Log4j的依赖时将Log4j添加到引导加载程序类路径。

无法创建类org.apache.logging.log4j.core.impl.Log4jContextFactory

3 个答案: