介绍：

我正在尝试使用log4j记录其他字段，并且它的工作原理，但只有当我在代码中创建追加器而不是在log4j.properties中创建追加器时

进展：

1. 本文使用了将转换字符添加到 log4j 1.1.3 的 PatternLayout
2. 为log4j 1.2制作了一个示例应用程序

问题：

使用它将运行的属性文件，但不会使用 AppServerPatternLayout，因此不会显示自定义字段。

下载代码

customlog.properties

log4j.rootLogger=FATAL
log4j.logger.some.log=INFO,stdout

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=logging.AppServerPatternLayout
log4j.appender.stdout.layout.ConversionPattern=-----------------using log file------------------------%nTime:      %d%nHost:      %h%nServer:    %s%nComponent: %b%nVersion:   %v%nPriority:  %p%nThread Id: %t%nContext:   %x%nMessage:   %m%n

主.java不带 log4j 属性文件的日志记录

AppServerLoggerFactory factory;
factory = new AppServerLoggerFactory("MyServer", "MyComponent", "1.0");
AppServerLogger.setFactory(factory);
Logger logger = AppServerLogger.getLogger("some.log");
PatternLayout layout = new AppServerPatternLayout( formatString );
logger.addAppender( new ConsoleAppender(layout) );
logger.info("Hello");

主.java log4j 属性文件的日志记录

PropertyConfigurator.configure("customlog.properties");
AppServerLoggerFactory factory;
factory = new AppServerLoggerFactory("MyServer", "MyComponent", "1.0");
AppServerLogger.setFactory(factory);
Logger logger = AppServerLogger.getLogger("some.log");
logger.info("Hello");

预期输出

----------------using in code appender----------------------
Time:      2009-11-06 12:55:05,785
Host:      M1330
Server:    MyServer
Component: MyComponent
Version:   1.0
Priority:  INFO
Thread Id: main
Context:   
Message:   logging config from code

实际输出

-----------------using log file------------------------
Time:      2009-11-06 12:56:17,983
Host:      
Server:    
Component: 
Version:   
Priority:  INFO
Thread Id: main
Context:   
Message:   logging config from customlog.properties

溶液

使用 MDC，您可以添加自定义字段，例如

MDC.put("Version", versionName);
Logger log = LogManager.getLogger("some.log");        
log.info("Hello");

并将其拉出在log4j.properties中，大写X

log4j.appender.stdout.layout.ConversionPattern=%X{Version}