Log4j JDBCAppender to log stacktraces

Question

Using org.apache.log4j.jdbc.JDBCAppender, how can I get stracktraces logged with warn and error into the PatternLayout.

Answer 1

log4j 1.2.16+ 's EnhancedPatternLayout is not work! because it extends org.apache.log4j.Layout rather than org.apache.log4j.PatternLayout, but in JDBCAppender:

public void setSql(String s) {
    sqlStatement = s;
    if (getLayout() == null) {
        this.setLayout(new PatternLayout(s));
    }
    else {
        ((PatternLayout)getLayout()).setConversionPattern(s);  //Point1
    }
}

So if you use JDBCAppender like this:

log4j.appender.JDBC=org.apache.log4j.jdbc.JDBCAppender    
log4j.appender.JDBC.layout=org.apache.log4j.EnhancedPatternLayout
log4j.appender.JDBC.sql=INSERT INTO email_send_error(insert_date, level, location, message, stacktrace) VALUES (now(), '%p', '%C,%L', '%m', '%throwable{short}')

will throw a ClassCastException in Point1:

Caused by: java.lang.ClassCastException: org.apache.log4j.EnhancedPatternLayout cannot be cast to org.apache.log4j.PatternLayout
at org.apache.log4j.jdbc.JDBCAppender.setSql(JDBCAppender.java:330)

EDIT (after in-depth research):
Use log4j.appender.JDBC.layout.ConversionPattern instead of log4j.appender.JDBC.sql, will avoid above ClassCastException:

 log4j.appender.JDBC.layout.ConversionPattern=INSERT INTO email_send_error(insert_date, level, location, message, stacktrace) VALUES (now(), '%p', '%C,%L', '%m', '%throwable{short}')

and don't forget record the throwed exception to logger:

logger.error(String errorMsg, Throwabe e); // Dont forget e