Question

我无法弄清楚为什么log4j会以不同的格式附加两次。有没有人遇到过这个？

这是我的log4j.xml文件：

<log4j:configuration>

    <appender name="async" class="org.apache.log4j.AsyncAppender">
    <!-- this parameter need to be set to false to avoid application from hanging. -->
        <param name="Blocking" value="false" />
        <appender-ref ref="myAppender" />
    </appender>

    <appender name="myAppender" class="org.apache.log4j.ConsoleAppender">
        <param name="Threshold" value="INFO" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%-5p %d{ISO8601} [%t] %c %x - %m%n" />
        </layout>
    </appender>

    <logger name="com.server">
        <level value="INFO" />
    </logger>

    <logger name="org.springframework">
        <level value="INFO" />
    </logger>

    <logger name="org.hibernate.LazyInitializationException" additivity="false">
       <level value="off" />
       <appender-ref ref="async" />
    </logger>

    <logger name="net.sf.ehcache">
        <level value="INFO" />
    </logger>

     <logger name="com.mchange">
         <level value="INFO" />
     </logger>

     <root>
         <priority value="INFO" />
         <appender-ref ref="async" />
     </root>

</log4j:configuration>

以下是一些示例输出：

INFO  2016-08-26 11:01:38,353 [main] com.server.Server  - Server started successfully...
11:01:38,353 INFO :  Server started successfully...

编辑：当我更改＆＃34; myAppender＆＃34; appender threshold to＆＃34; ERROR＆＃34;，显示的第二条日志消息（一个以时间开头，而不是＆＃34; INFO＆＃34;）仍在生成。我需要禁用一些默认记录器吗？似乎某些东西仍在记录那些＆＃34; INFO＆＃34;级别消息，即使指定的appender用于＆＃34; ERROR＆＃34;级别消息。此外，如果我注释掉整个log4j.xml文件，则仍会记录第二条日志消息（以及所有类似的消息）。我怎么能阻止这个？谢谢！

Answer 1

我不熟悉log4j的XML语法（我使用log4j.properties进行配置）所以这是我的2美分，试图帮助您调试和修复代码。

首先尝试使用以下根记录器配置而不是你的<appender-ref ref="async" /> -

<logger name="org.hibernate.LazyInitializationException" additivity="false">
   <level value="off" />
   <appender-ref ref="myAppender" />
</logger>
..............
...........
 <root>
     <priority value="INFO" />
     <appender-ref ref="myAppender" />
 </root>

如果以上情况不起作用，请尝试将<param name="Threshold" value="ERROR" />放在async和myAppender中，我想不会打印Server started successfully日志（我认为您已尝试使用myAppender）

如果这有帮助，那么这意味着您尝试引用/继承记录器的方式无法正常工作或使用，因此您从这个方向思考并纠正问题，您需要阅读更多关于{{ 1}}元素和appender-ref记录器。

无论上述是否有效，我猜你正在努力实现以下目标 -

打印您的标准输入/输出，即您的终端窗口
在文件中打印以及生产环境

我会在log4j.properties中执行此操作，如下所示：

AsyncAppender

所以，我想你可以做如下的事情。

log4j.logger.com.sks.cs50=DEBUG, CS50GlobalFileAppender, stdout

#####CS50 Web log##########
log4j.appender.CS50GlobalFileAppender=org.apache.log4j.RollingFileAppender
log4j.appender.CS50GlobalFileAppender.File=${logDir}cs50.log
log4j.appender.CS50GlobalFileAppender.MaxBackupIndex=50
log4j.appender.CS50GlobalFileAppender.Threshold=DEBUG
log4j.appender.CS50GlobalFileAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.CS50GlobalFileAppender.layout.ConversionPattern=%C %d [%t] [%X{randomNumber}] %-5p - %m%n
log4j.appender.CS50GlobalFileAppender.MaxFileSize=500000KB

# Log format to standard output
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d [%X{randomNumber}] %-5p - %m%n

log4j.logger.org.apache = INFO
log4j.logger.com.sun = INFO
log4j.logger.sun = INFO
log4j.logger.javax.xml.bind = INFO
log4j.logger.org.springframework = INFO
log4j.logger.com.cgi = DEBUG

请注意以上的XML配置假设<log4j:configuration> <appender name="async" class="org.apache.log4j.AsyncAppender">  <param name="Blocking" value="false" /> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="%-5p %d{ISO8601} [%t] %c %x - %m%n" /> </layout> </appender> <appender name="myAppender" class="org.apache.log4j.ConsoleAppender"> <param name="Threshold" value="INFO" /> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="%-5p %d{ISO8601} [%t] %c %x - %m%n" /> </layout> </appender> <logger name="com.server"> <level value="INFO" /> </logger> <logger name="org.springframework"> <level value="INFO" /> </logger> <logger name="org.hibernate.LazyInitializationException" additivity="false"> <level value="off" /> <appender-ref ref="async" /> </logger> <logger name="net.sf.ehcache"> <level value="INFO" /> </logger> <logger name="com.mchange"> <level value="INFO" /> </logger> <root> <priority value="INFO" /> <appender-ref ref="async" /> <appender-ref ref="myAppender" /> </root> </log4j:configuration>打印在某个日志文件中，但如果它没有（我猜它没有＆＃39; t）然后上面将无法工作（如果用org.apache.log4j.AsyncAppender替换AsyncAppender，你仍然可以使用上面的XML配置来实现文件+控制台记录，我想知道你为什么不能这样做直接使用org.apache.log4j.RollingFileAppender因为它已经打印到控制台，所以可能只是使用：

org.apache.log4j.AsyncAppender

Answer 2

为什么Log4j会记录两次？

Log4j会记录层次结构中的所有记录器，除非您不这样做要（通过将additivity设置为false），您就会看到输出来自您的com.server记录器和默认的ROOT记录器永远存在。

针对上述问题的解决方案

这种情况正在发生，因为你还没有定义您的 com.server 记录器上的 additivity =＆＃34; false＆＃34; 属性。现在我修好了，你可以试试。

<appender name="async" class="org.apache.log4j.AsyncAppender">
<!-- this parameter need to be set to false to avoid application from hanging. -->
    <param name="Blocking" value="false" />
    <appender-ref ref="myAppender" />
</appender>

<appender name="myAppender" class="org.apache.log4j.ConsoleAppender">
    <param name="Threshold" value="INFO" />
    <layout class="org.apache.log4j.PatternLayout">
        <param name="ConversionPattern" value="%-5p %d{ISO8601} [%t] %c %x - %m%n" />
    </layout>
</appender>

<logger name="com.server" additivity="false">
    <level value="INFO" />
</logger>

<logger name="org.springframework">
    <level value="INFO" />
</logger>

<logger name="org.hibernate.LazyInitializationException" additivity="false">
   <level value="off" />
   <appender-ref ref="async" />
</logger>

<logger name="net.sf.ehcache">
    <level value="INFO" />
</logger>

 <logger name="com.mchange">
     <level value="INFO" />
 </logger>

 <root>
     <priority value="INFO" />
     <appender-ref ref="async" />
 </root>

Answer 3

我的猜测是，在您的应用程序中的某个地方，会以编程方式添加另一个appender，可能是这样的：

package de.scrum_master.app;

import java.io.OutputStreamWriter;

import org.apache.log4j.ConsoleAppender;
import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;

public class Application {
    private static Logger log = Logger.getLogger(Application.class);

    public static void main(String[] args) throws InterruptedException {
        //log.setAdditivity(false);
        ConsoleAppender ca = new ConsoleAppender();
        ca.setWriter(new OutputStreamWriter(System.out));
        ca.setLayout(new PatternLayout("%-5p [%t]: %m%n"));
        log.addAppender(ca);
        log.info("Hello world");
        log.info("Bye world");
        Thread.sleep(1000);
    }
}

除了在类路径中找到的 log4j.xml 或 log4j.properties 文件外，还会导致您在日志中看到的效果。

更新：或者甚至可能会调用类似Logger.getRootLogger().addAppender(ca)的内容，影响根记录器，而不仅仅是一个特定的记录器。

使用您的配置文件，这会产生以下日志输出：

INFO  [main]: Hello world
INFO  [main]: Bye world
INFO  2016-09-04 13:48:25,887 [main] de.scrum_master.app.Application  - Hello world
INFO  2016-09-04 13:48:25,889 [main] de.scrum_master.app.Application  - Bye world

Answer 4

已经有了一些答案，所以我继续创建了一个程序来证明这确实有效，除非你的代码中存在一些问题 - 请参阅下面的两个简单类，并尝试找出这些和你的之间的区别

import org.apache.log4j.xml.DOMConfigurator;

import com.server.Test;

public class MyListener {
public static void main(String[] args) {

    DOMConfigurator.configure("/home/sanjeevd/depot/bas/projects/xxx.1/yyy/src/log4j.xml");

    Test test = new Test();
}

}

package com.server;

import org.apache.log4j.Logger;

public class Test {

private static Logger logger = Logger.getLogger(Test.class);

public Test() {
    logger.info("PRINTTTTTTTTTTTT");
}

}

还要在log4j.xml的顶部添加这两行 -

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

话虽如此，我很确定有一些其他记录器已经初始化或者你的应用程序中有多个lo4j.xml等。请注意，我没有更改log4j.xml中的任何内容而不是添加标题。

输出低于（并打印出来） -

INFO  2016-09-06 10:57:37,506 [main] com.server.Test  - PRINTTTTTTTTTTTT

你应该做的另一件事是为引导程序调试设置“系统属性”，看看在log4j级别发生了什么，即放

System.setProperty("log4j.debug", "true");

在配置log4j之前。如果要将它部署到某个servlet容器（tomcat等）上，那么在启动期间传递-Dlog4j.debug = true参数。

我的案例中的输出是 -

log4j: Trying to find [log4j.xml] using context classloader   sun.misc.Launcher$AppClassLoader@42a57993.
log4j: Using URL [file:/home/sanjeevd/depot/bas/projects/xxx.1/yyy/bin/log4j.xml] for automatic log4j configuration.
log4j: Preferred configurator class: org.apache.log4j.xml.DOMConfigurator
log4j: System property is :null
log4j: Standard DocumentBuilderFactory search succeded.
log4j: DocumentBuilderFactory is: com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl
log4j: debug attribute= "null".
log4j: Ignoring debug attribute.
log4j: reset attribute= "false".
log4j: Threshold ="null".
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [com.server] additivity to [true].
log4j: Level value for com.server is  [INFO].
log4j: com.server level set to INFO
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [org.springframework] additivity to [true].
log4j: Level value for org.springframework is  [INFO].
log4j: org.springframework level set to INFO
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [org.hibernate.LazyInitializationException] additivity to [false].
log4j: Level value for org.hibernate.LazyInitializationException is  [off].
log4j: org.hibernate.LazyInitializationException level set to OFF
log4j: Class name: [org.apache.log4j.AsyncAppender]
log4j: Attaching appender named [myAppender] to appender named [async].
log4j: Class name: [org.apache.log4j.ConsoleAppender]
log4j: Setting property [threshold] to [INFO].
log4j: Setting property [target] to [System.out].
log4j: Parsing layout of class: "org.apache.log4j.PatternLayout"
log4j: Setting property [conversionPattern] to [%-5p %d{ISO8601} [%t] %c %x - %m%n].
log4j: Adding appender named [async] to category [org.hibernate.LazyInitializationException].
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [net.sf.ehcache] additivity to [true].
log4j: Level value for net.sf.ehcache is  [INFO].
log4j: net.sf.ehcache level set to INFO
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [com.mchange] additivity to [true].
log4j: Level value for com.mchange is  [INFO].
log4j: com.mchange level set to INFO
log4j: Level value for root is  [INFO].
log4j: root level set to INFO
log4j: Adding appender named [async] to category [root].
log4j: System property is :null
log4j: Standard DocumentBuilderFactory search succeded.
log4j: DocumentBuilderFactory is: com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl
log4j: debug attribute= "null".
log4j: Ignoring debug attribute.
log4j: reset attribute= "false".
log4j: Threshold ="null".
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [com.server] additivity to [true].
log4j: Level value for com.server is  [INFO].
log4j: com.server level set to INFO
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [org.springframework] additivity to [true].
log4j: Level value for org.springframework is  [INFO].
log4j: org.springframework level set to INFO
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [org.hibernate.LazyInitializationException] additivity to [false].
log4j: Level value for org.hibernate.LazyInitializationException is  [off].
log4j: org.hibernate.LazyInitializationException level set to OFF
log4j: Class name: [org.apache.log4j.AsyncAppender]
log4j: Attaching appender named [myAppender] to appender named [async].
log4j: Class name: [org.apache.log4j.ConsoleAppender]
log4j: Setting property [threshold] to [INFO].
log4j: Setting property [target] to [System.out].
log4j: Parsing layout of class: "org.apache.log4j.PatternLayout"
log4j: Setting property [conversionPattern] to [%-5p %d{ISO8601} [%t] %c %x - %m%n].
log4j: Adding appender named [async] to category [org.hibernate.LazyInitializationException].
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [net.sf.ehcache] additivity to [true].
log4j: Level value for net.sf.ehcache is  [INFO].
log4j: net.sf.ehcache level set to INFO
log4j: Retreiving an instance of org.apache.log4j.Logger.
log4j: Setting [com.mchange] additivity to [true].
log4j: Level value for com.mchange is  [INFO].
log4j: com.mchange level set to INFO
log4j: Level value for root is  [INFO].
log4j: root level set to INFO
log4j: Adding appender named [async] to category [root].

Answer 5

我认为将 additivity =“false”添加到 com.server 记录器可以解决问题。

    <logger name="com.server" additivity="false">
        <level value="INFO" />
    </logger>

https://logging.apache.org/log4j/2.x/manual/configuration.html#Additivity

Answer 6

问题解决了，我必须这样做：

<logger name="com.server" additivity="false">
    <level value="INFO" />
    <appender-ref ref="async" />
</logger>

Log4j使用不同格式

6 个答案: