扩展log4j系列[一]DailyRollingFileAppender的按分钟生成日志修改为按n分钟生成日志

复制DailyRollingFileAppender里面的源码，放在新命名的类public class MinuteRollingFileAppender extends FileAppender的里面，修改两个主要地方：

 

void rollOver() throws IOException {

    /* Compute filename, but only if datePattern is specified */
    if (datePattern == null) {
      errorHandler.error("Missing DatePattern option in rollOver().");
      return;
    }

    String datedFilename = fileName+sdf.format(now);
    // It is too early to roll over because we are still within the
    // bounds of the current interval. Rollover will occur once the
    // next interval is reached.
    if (scheduledFilename.equals(datedFilename)) {
      return;
    }

    // close current file, and rename it to datedFilename
    this.closeFile();

    //File target  = new File(scheduledFilename);
   

//modify start------
   
    Calendar rollTime = Calendar.getInstance();
    rollTime.add(Calendar.MINUTE, -1);
   
    log.debug(" ＝＝＝＝＝ log4j rolled file time :" + rollTime.getTime());
   
    String minuteLog =  fileName+sdf.format(rollTime.getTime());
    File target  = new File(minuteLog);
//modify end------
   
    if (target.exists()) {
      target.delete();
    }

    File file = new File(fileName);
    boolean result = file.renameTo(target);
    if(result) {
      LogLog.debug(fileName +" -> "+ scheduledFilename);
    } else {
      LogLog.error("Failed to rename ["+fileName+"] to ["+scheduledFilename+"].");
    }

    try {
      // This will also close the file. This is OK since multiple
      // close operations are safe.
      this.setFile(fileName, false, this.bufferedIO, this.bufferSize);
    }
    catch(IOException e) {
      errorHandler.error("setFile("+fileName+", false) call failed.");
    }
    scheduledFilename = datedFilename;
  }

 

 

//下面是按每隔15分钟生成一个日志

public Date getNextCheckDate(Date now) {
    this.setTime(now);

    switch(type) {
    case MinuteRollingFileAppender.TOP_OF_MINUTE:
 this.set(Calendar.SECOND, 0);
 this.set(Calendar.MILLISECOND, 0);
//modify start------ 
 this.add(Calendar.MINUTE, 15);
// modify end------
 break;
    default:
 throw new IllegalStateException("Unknown periodicity type.");
    }
    return getTime();
  }

 

 

 

//下面是在打印日志的事件里面过滤信息

    protected void subAppend(LoggingEvent event) {
        long n = System.currentTimeMillis();
        if (n >= nextCheck) {
            now.setTime(n);
            nextCheck = rc.getNextCheckMillis(now);
            try {
                rollOver();
            }
            catch (IOException ioe) {
                LogLog.error("rollOver() failed.", ioe);
            }
        }
        log.debug(" == MinuteRollingFileAppender test LoggingEvent' message :" + event.getMessage());
        String obj = this.layout.format(event);

        //下面过滤掉空格、空行（注：linux下要加“/r/n”过滤才生效）
        if (obj == null || obj.equals("")||obj.equals(" /r/n") || obj.equals(" /n"))  
            return;
        super.subAppend(event);
    }