如何使用属性文件在 log4j.xml 中设置值？

Question

I would like to know if there is possibility to set an attribute in log4j.xml by using property file. For example the log4j.xml:

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration>
 <appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender">
    <param name="target" value="System.out" />
    <layout class="org.apache.log4j.PatternLayout">
        <param name="ConversionPattern" value="%d{ISO8601} %-5p [%c{1}] - %l - %m%n "/>
    </layout>        
</appender>
   <appender name="FILE" class="org.apache.log4j.FileAppender">
<param name="File" value="\D:\ReadText_File\log4jlogss.txt"/>
<param name="Append" value="true"/>
         <layout class="org.apache.log4j.PatternLayout">
                    <param name="ConversionPattern" value="%d{ISO8601} %-5p [%c{1}]- %l - %m%n"/>
        </layout>
</appender>
<logger name="org.apache">
<level value="WARN"/>
</logger>
<root>
    <level value="DEBUG"/>
    <appender-ref ref="FILE"/>
    <appender-ref ref="CONSOLE"/>
    </root>
   </log4j:configuration>

I wan to specify the path for the file using Properties file Any idea how can we do it ????

Answer 1

about log4j, this type of configuration that XML configuration which embed the property file is not supported in current version.

for details, you can view the log4j's source code . the XML parse details is in class DOMConfigurator.configure

Answer 2

You can use Log4j Lookups with PropertySubstitution :

See http://logging.apache.org/log4j/2.x/manual/configuration.html#PropertySubstitution and http://logging.apache.org/log4j/2.x/manual/lookups.html

Here is an example on StackOverflow: Log4J2 property substitution - default (to make it short, you can use, as far as I know, the System Property using -Dkey=value )

You can also try to use the ${bundle:com.package.Messages:MyKey} syntax to use a properties file (using log4j 2.0-rc1 or greater), see https://stackoverflow.com/a/19303208/1149528 .