Log4j-使用DatePattern后文件扩展名（.log）消失

Question

I'm having a problem with my Log4j.xml file. When I save a log file like that:

<appender name="file" class="org.apache.log4j.DailyRollingFileAppender">
    <param name="append" value="true" />
    <param name="datePattern" value="_dd.MM.yyyy_HH.mm.ss" />
    <param name="file" value="/logs/dailyschedule.log" />
    <layout class="org.apache.log4j.PatternLayout">
        <param name="ConversionPattern" 
                   value="%d{dd.MM.yyyy HH:mm:ss} class:[%c] method:[%t] [%-5p] : %m%n"/>
    </layout>
</appender>

the file is ok, but has no file extension. Is it a bug or I'm doing something wrong?

Edit: Before I saw Paul's answer, I was temporarily solved my problem by using a simple class for initializing my logger. It wasn't the best decision, but it can be usefull to someone with similar problem:

public class DomainLogger {

private Logger logger = null;

public DomainLogger(String directoryName, String fileName) throws Exception {

    SimpleDateFormat sdf = new SimpleDateFormat("_dd.MM.yyyy");
    String timeNow = sdf.format(new Date());

    String fullFilePath = System.getenv("DOMAIN_HOME") + 
            directoryName + "\\" + 
            fileName + timeNow + ".log";
    System.out.println("full filepath is " + fullFilePath);

    logger = Logger.getLogger(timeNow);
    //warning! different time will create a new file !!!

    PatternLayout patternLayout = new PatternLayout("%m%n");
    FileAppender fileAppender = new FileAppender(patternLayout, fullFilePath);
    logger.addAppender(fileAppender);
}

public void writeLog(String logMessage) {
    logger.info(logMessage);
}

}

Answer 1

If you're using log4j 1.x, we strongly recommend that you use org.apache.log4j.rolling.RollingFileAppender instead of org.apache.log4j.DailyRollingFileAppender (may lose messages, Bug 43374 ).

So the configuration of you appender can be:

<appender name="file" class="org.apache.log4j.rolling.RollingFileAppender">
    <param name="encoding" value="UTF-8" />
    <rollingPolicy class="org.apache.log4j.rolling.TimeBasedRollingPolicy">
        <param name="activeFileName" value="/logs/dailyschedule.log" />
        <param name="fileNamePattern" 
               value="/logs/dailyschedule%d{_dd.MM.yyyy_HH.mm.ss}.log" />
    </rollingPolicy>
    <layout class="org.apache.log4j.PatternLayout">
        <param name="conversionPattern" 
               value="%d{dd.MM.yyyy HH:mm:ss} class:[%c] method:[%t] [%-5p] : %m%n" />
    </layout>
</appender>

Using this configuration, you will get finenames like the next:

dailyschedule.log
dailyschedule_28.08.2014_14.57.45.log
dailyschedule_28.08.2014_14.57.46.log
dailyschedule_28.08.2014_14.57.47.log
dailyschedule_28.08.2014_14.57.48.log
dailyschedule_28.08.2014_14.57.49.log

---

Notes

1. In that case, you need to add the respective jar ( apache-log4j-extras-1.2.17.jar ).
2. If you don't want the first filename ( dailyschedule.log ), drop the param activeFileName in the rolling policy.