log4j SMTPAppender sending mail with empty mail body

问题

In my grails app I have lg4j config as follows

log4j = {
    error 'org.codehaus.groovy.grails.web.servlet',         //  controllers
        'org.codehaus.groovy.grails.web.pages',             //  GSP
        'org.codehaus.groovy.grails.web.sitemesh',          //  layouts
        'org.codehaus.groovy.grails.web.mapping.filter',    // URL mapping
        'org.codehaus.groovy.grails.web.mapping',           // URL mapping
        'org.codehaus.groovy.grails.commons',               // core / classloading
        'org.codehaus.groovy.grails.plugins',               // plugins
        'org.codehaus.groovy.grails.orm.hibernate',         // hibernate integration,
        'net.sf.ehcache.hibernate'

    warn 'org.hibernate', 'grails.app', 'org.springframework', 'org.springframework.security'

    info 'org.springframework', 'org.springframework.security', 'grails.app'

    appenders {
        def patternLayout = new PatternLayout()
        patternLayout.setConversionPattern("[%r] %c{2} %m%n")
        def mailAppender = new SMTPAppender()
        mailAppender.setFrom("from@webbfontaine.am")
        mailAppender.setTo("to@webbfontaine.am")
        mailAppender.setSubject("[Error in application] [host:test.am]")
        mailAppender.setSMTPHost("smtp.test.am")
        mailAppender.setLayout(patternLayout)
        mailAppender.setThreshold(org.apache.log4j.Level.WARN)
        appender name:'mail', mailAppender
    }

    root {
        warn 'mail', 'stdout'
    }
}

It works fine and sends mail when I run my app with grails run-app, but when I deploy war under tomcat, I get emails with empty body. Is there some specific jar that should be under tomcat/libs? Any ideas?

来源：https://stackoverflow.com/questions/20073084/log4j-smtpappender-sending-mail-with-empty-mail-body