Log different level to different appender in log4j

log4j.properties

### file appender
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.maxFileSize=100KB
log4j.appender.file.maxBackupIndex=5
log4j.appender.file.File=test.log
#NOTE:
log4j.appender.file.threshold=info
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
 
#email appender
log4j.appender.mail=org.apache.log4j.net.SMTPAppender
#defines how othen emails are send
log4j.appender.mail.BufferSize=1
log4j.appender.mail.SMTPHost="smtp.myservername.xx"
log4j.appender.mail.From=fromemail@myservername.xx
log4j.appender.mail.To=toemail@myservername.xx
log4j.appender.mail.Subject=Log ...
#NOTE:
log4j.appender.mail.threshold=error
log4j.appender.mail.layout=org.apache.log4j.PatternLayout
log4j.appender.mail.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

log4j.rootLogger=warn, file, mail