为了演示我的问题，假设我们有一个简单的应用程序，它有一个顶级包com.foo，以及ui（com.foo.ui）和server（com.foo.server）的子包。我还没有能够编造一个log4j属性文件，这将确保以下内容：

* all ERROR level logging statements in packages including and descending from com.foo are
captured in a separate file under logs/main.log

* any and all messages at any levels (DEBUG,TRACE,INFO,WARN,ERROR) go to both stdout and the file appender.

下面是我尝试过的两个log4j配置和这个玩具应用程序的所有代码。我在运行这个玩具应用程序时遇到的挑战是logs/main.log包含所有级别的消息，而不仅仅是ERROR级别的消息。

首次尝试

#Define root logger options
log4j.rootLogger=TRACE, file, stdout

#Define stdout appender
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
logrj.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%-5p %c{1} - %m%n

#Define rolling file appender
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=logs/main.log
log4j.appender.file.Append=true
log4j.appender.file.ImmediateFlush=true
log4j.appender.file.MaxFileSize=10MB
log4j.appender.file.MaxBackupIndex=5
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d %d{Z} [%t] %-5p (%F:%L) - %m%n
log4j.appender.error-log.filter.b=org.apache.log4j.varia.LevelMatchFilter
log4j.appender.error-log.filter.LevelToMatch = ERROR
log4j.appender.error-log.filter.AcceptOnMatch = true
log4j.appender.error-log.Threshold = ERROR

#Define loggers
log4j.logger.com.foo.log4j=TRACE, file, stdout

第二次尝试**

#Define root logger options
log4j.rootLogger=TRACE, file, stdout

#Define stdout appender
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
logrj.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%-5p %c{1} - %m%n

#Define rolling file appender
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=logs/main.log
log4j.appender.file.Append=true
log4j.appender.file.ImmediateFlush=true
log4j.appender.file.MaxFileSize=10MB
log4j.appender.file.MaxBackupIndex=5
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d %d{Z} [%t] %-5p (%F:%L) - %m%n
log4j.appender.error-log.filter.b=org.apache.log4j.varia.LevelRangeFilter
log4j.appender.error-log.filter.LevelMin = ERROR
log4j.appender.error-log.filter.LevelMax = ERROR
log4j.appender.error-log.filter.AcceptOnMatch = true
log4j.appender.error-log.Threshold = ERROR

#Define loggers
log4j.logger.com.foo.log4j=TRACE, file, stdout

构建依赖

以下是我使用的构建依赖项：

plugins {
    // Apply the scala plugin to add support for Scala
    id 'scala'

    // Apply the java-library plugin for API and implementation separation.
    id 'java-library'
}

repositories {
    // Use jcenter for resolving dependencies.
    // You can declare any Maven/Ivy/file repository here.
    jcenter()
}

dependencies {
    // Use Scala 2.13 in our library project
    implementation 'org.scala-lang:scala-library:2.13.2'
    implementation 'org.apache.logging.log4j:log4j-api:2.17.0'
    implementation 'org.apache.logging.log4j:log4j-core:2.17.0'

    // Use Scalatest for testing our library
    testImplementation 'junit:junit:null'
    testImplementation 'org.scalatest:scalatest_2.13:3.1.2'
    testImplementation 'org.scalatestplus:junit-4-12_2.13:3.1.2.0'
    implementation 'log4j:log4j:1.2.17'

    // Need scala-xml at test runtime
    testRuntimeOnly 'org.scala-lang.modules:scala-xml_2.13:1.2.0'
}

班级

下面是App中的三个简单的小类：

------------------------------------
package com.foo

import com.foo.server.Server
import com.foo.ui.UI

object Application extends App {
  val server = Server()
  val ui = new UI(server)
  ui.message("hello")
}

------------------------------------
package com.foo.ui

import com.foo.server.Server
import org.apache.log4j.LogManager

class UI(server: Server) { // mine

  val log = LogManager.getLogger(this.getClass)

  def message(string: String): Unit = {
    log.trace("ui got message " + string)
    server.message(string)
  }
}

------------------------------------
package com.foo.server

import org.apache.log4j.LogManager

case class Server() {
  val log = LogManager.getLogger(this.getClass)

  def message(string: String): Unit = {
    log.info("server got message "+ "message")
    log.error("server raised erorr on  message "+ "message")
  }
}