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

Question

我正在为项目使用 spring boot 应用程序，在使用 java -jar build/libs/com.user.admin.rest.services.jar 从 jar 运行项目时出现以下错误。但它不是阻止程序，我能够访问 api，并且记录器按预期工作正常。我只想解决这个错误。

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 文件中为记录器添加了以下行。

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

下面给出了我的 log4j2.xml 文件

<?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

Generally speaking, you should never need to switch logging implementations; Logback should suit you fine. However, if you decide that you’d rather use Log4j or Log4j2, you’ll need to change your dependencies to include the appropriate starter for the logging implementation you want to use and to exclude Logback.
Spring Boot in Action

在 Gradle 中将 Logback 换成 Log4j2

1. 排除默认日志记录

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

1. 添加 Log4j2 日志

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

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