通過LogManger.getLogger（）獲取自定義記錄器

Question

我想知道如何通過log4j的LogManger.getLogger（）方法獲得自定義記錄器 。

我幾乎可以肯定我的項目不需要自定義記錄器，並使用默認的log4j記錄器。

但是，如果有必要，我想用我的自定義記錄器更改源代碼中的所有記錄器。

只需更改設置文件或LoggerFactory源代碼即可嗎？

如果這篇文章重複，請把鏈接引導到那裏。

謝謝。

Answer 1

推薦的方法是修改配置文件並將watch標誌設置爲true。如果你想推進做源代碼的方法，請參閱下文。

這是一個相當複雜的過程，其中包括轉換爲log4j.core.logger類型以公開被Logger界面隱藏的受保護方法。我還應該聲明，這涉及到core.logger中的受保護方法，這些方法隨時都可能發生變化。

爲你幸運我剛剛解決了這個問題，並有示例代碼。

/** 
* Dynamically creates an instance of a Logger. 
* 
* @param appenderName 
*   most often will be the name of the class this logger will 
*   belong to. 
* @param logFileName 
*   the file name to save the logs to 
* @return 
*/ 
public static org.apache.logging.log4j.Logger createInstanceLogger(String appenderName, 
     String logFileName) { 
    //call getLogger() which will create and load a logger with a default configuration 
    org.apache.logging.log4j.Logger logger = org.apache.logging.log4j.LogManager 
      .getLogger(String.format("DynamicLogger%s", 
        String.valueOf(DynamicLogManager.loggerCount++))); 
    org.apache.logging.log4j.core.Logger coreLogger = (org.apache.logging.log4j.core.Logger) logger; // cast logger to core logger to access protected methods 
    org.apache.logging.log4j.core.LoggerContext context = coreLogger.getContext(); 
    org.apache.logging.log4j.core.config.BaseConfiguration configuration = (org.apache.logging.log4j.core.config.BaseConfiguration) context 
      .getConfiguration(); 

    TriggeringPolicy compositePolicy = CompositeTriggeringPolicy.createPolicy(
      SizeBasedTriggeringPolicy.createPolicy("5mb"), 
      TimeBasedTriggeringPolicy.createPolicy("1", "true")); 

    String fileName = String.format("%1$s/%2$s", appenderName, logFileName); 
    String filePattern = String.format("%1$s/%2$s.%%d{yyyy-MM-dd}", 
      appenderName, logFileName); 

    Layout<String> layout = PatternLayout.createLayout(DynamicLogManager._conversionPattern, 
      configuration, RegexReplacement.createRegexReplacement("a^", "."), //empty regex replacement 
      "utf-8", "false"); 

    Filter f = ThresholdFilter.createFilter("trace", "accept", "accept"); 

    Appender a = RollingFileAppender.createAppender(fileName, //fileName 
      filePattern, //filePattern 
      "true", //append 
      appenderName, //appender name 
      "true", //bufferred io 
      "true", //immediate flush 
      compositePolicy, //policy 
      null, //strategy default 
      layout, //layout 
      f, //filter none 
      "true", //ignore exceptions 
      "false", //advertise 
      "null", //advertise uri 
      configuration //configuration 
      ); 

    a.start(); 

    coreLogger.addAppender(a); 

    //this is where we would figure out how to configure the logger to listen on a configuration file 
    coreLogger.setLevel(Level.ALL); //set the log level of the logger that we are returning to Level.ALL 

    return coreLogger; //cast logger back to Logger interface 

編輯您的評論如下：

好像你只是想你的記錄添加到您的xml配置，並從Java代碼抓住它，這是很容易做到的...

<Loggers> 
    <Logger name="com.foo.Bar" level="trace" additivity="false"> 
     <AppenderRef ref="whateverAppenderName"/> 
    </Logger> 
    <Root level="error"> 
     <AppenderRef ref="whateverOtherAppenderName"/> 
    </Root> 
    </Loggers> 

然後在Java代碼：

package com.foo; 
class Bar{ 
private static final Logger log = LogManager.getLogger(); //qualified class name is com.foo.Bar 
} 

登錄log4j也是層次結構。這意味着如果你定義了一個名爲「com.foo」的記錄器，它將被該包的所有孩子抓住，如果它是最容易到達的記錄器（這意味着，你沒有針對該特定類的更具體的記錄器名稱）

閱讀本文... http://logging.apache.org/log4j/2.x/manual/configuration.html#XML

Answer 2

請看看https://issues.apache.org/jira/browse/LOG4J2-519

注意，附加到票證上的密碼生成器與此工具的log4j-2.0的未來版本可能會破壞產生的試驗和定製/擴展記錄儀。