删除N天前的log4j日志的方法

这个方式是采用的RollingFileAppender, 然后通过设置maxBackupIndex属性来指定要保留的日志的最大值(这里采用一天一个日志).但是我们一直采用的是 DailyRollingFileAppender. 可是该appender没有maxBackupIndex这个属性, 于是又google了一把, 发现老外也想到的解决办法, 而且这里有两个解决方法, 即在RollingFileAppender的基础上, 加入了maxBackupIndex属性.

/**************************
* Zybocodes *******************************
* Code For :
* log4j custom DailyRollingFileAppender - manage your
* logs:maxBackupIndex zip roll archive logging log management
* logs
* Contributor : Ed Sarrazin
* Ref link : http://jconvert.sourceforge.net
* For this and other codes/logic under any technology visit:
* http://www.zybonics.com/zybocodes/
********************************************************************/

/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package logger;

import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InterruptedIOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

import org.apache.log4j.FileAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LoggingEvent;

/**
* @author Ed Sarrazin
* <pre>
* AdvancedDailyRollingFileAppender is a copy of apaches DailyRollingFileAppender. This copy was made because it could not be extended due to package level access. This new version will allow two new properties to be set:
* MaxNumberOfDays: Max number of log files to keep, denoted in days. If using compression, this days should be longer than
* - CompressBackupsAfterDays and will become irrelevant as files will be moved to archive before this time.
* CompressBackups: Indicating if older log files should be backed up to a compressed format.
* RollCompressedBackups: TURE/FALSE indicating that compressed backups should be rolled out (deleted after certain age)
* CompressBackupsAfterDays: Number of days to wait until adding files to compressed backup. (Files that are compressed are deleted)
* CompressBackupsDatePattern: example - "'.'yyyy-MM" - this will create compressed backups grouped by pattern. In this example, every month
* CompressMaxNumberDays: Number of days to keep compressed backups. RollCompressedBackups must be true.
*
* Here is a listing of the log4j.properties file you would use:
*
* log4j.appender.RootAppender=com.edsdev.log4j.AdvancedDailyRollingFileAppender
* log4j.appender.RootAppender.DatePattern='.'yyyyMMdd
* log4j.appender.RootAppender.MaxNumberOfDays=60
* log4j.appender.RootAppender.CompressBackups=true
* log4j.appender.RootAppender.CompressBackupsAfterDays=31
* log4j.appender.RootAppender.CompressBackupsDatePattern='.'yyyyMM
* log4j.appender.RootAppender.RollCompressedBackups=true
* log4j.appender.RootAppender.CompressMaxNumberDays=365
*
* </pre>
* AdvancedDailyRollingFileAppender extends {@link FileAppender} so that the underlying file is rolled over at a user
* chosen frequency. AdvancedDailyRollingFileAppender has been observed to exhibit synchronization issues and data loss.
* The log4j extras companion includes alternatives which should be considered for new deployments and which are
* discussed in the documentation for org.apache.log4j.rolling.RollingFileAppender.
* 
* The rolling schedule is specified by the DatePattern option. This pattern should follow the
* {@link SimpleDateFormat} conventions. In particular, you must escape literal text within a pair of single
* quotes. A formatted version of the date pattern is used as the suffix for the rolled file name.
* 
* For example, if the File option is set to <code>/foo/bar.log</code> and the DatePattern set to
* <code>'.'yyyy-MM-dd</code>, on 2001-02-16 at midnight, the logging file <code>/foo/bar.log</code> will be copied
* to <code>/foo/bar.log.2001-02-16</code> and logging for 2001-02-17 will continue in <code>/foo/bar.log</code>
* until it rolls over the next day.
* 
* Is is possible to specify monthly, weekly, half-daily, daily, hourly, or minutely rollover schedules.
* 
* <table border="1" cellpadding="2">
* <tr>
* <th>DatePattern</th>
* <th>Rollover schedule</th>
* <th>Example</th>
* <tr>
* <td><code>'.'yyyy-MM</code>
* <td>Rollover at the beginning of each month</td>
* <td>At midnight of May 31st, 2002 <code>/foo/bar.log</code> will be copied to <code>/foo/bar.log.2002-05</code>.
* Logging for the month of June will be output to <code>/foo/bar.log</code> until it is also rolled over the next
* month.
* <tr>
* <td><code>'.'yyyy-ww</code>
* <td>Rollover at the first day of each week. The first day of the week depends on the locale.</td>
* <td>Assuming the first day of the week is Sunday, on Saturday midnight, June 9th 2002, the file /foo/bar.log
* will be copied to /foo/bar.log.2002-23. Logging for the 24th week of 2002 will be output to
* <code>/foo/bar.log</code> until it is rolled over the next week.
* <tr>
* <td><code>'.'yyyy-MM-dd</code>
* <td>Rollover at midnight each day.</td>
* <td>At midnight, on March 8th, 2002, <code>/foo/bar.log</code> will be copied to
* <code>/foo/bar.log.2002-03-08</code>. Logging for the 9th day of March will be output to <code>/foo/bar.log</code>
* until it is rolled over the next day.
* <tr>
* <td><code>'.'yyyy-MM-dd-a</code>
* <td>Rollover at midnight and midday of each day.</td>
* <td>At noon, on March 9th, 2002, <code>/foo/bar.log</code> will be copied to
* <code>/foo/bar.log.2002-03-09-AM</code>. Logging for the afternoon of the 9th will be output to
* <code>/foo/bar.log</code> until it is rolled over at midnight.
* <tr>
* <td><code>'.'yyyy-MM-dd-HH</code>
* <td>Rollover at the top of every hour.</td>
* <td>At approximately 11:00.000 o'clock on March 9th, 2002, <code>/foo/bar.log</code> will be copied to
* <code>/foo/bar.log.2002-03-09-10</code>. Logging for the 11th hour of the 9th of March will be output to
* <code>/foo/bar.log</code> until it is rolled over at the beginning of the next hour.
* <tr>
* <td><code>'.'yyyy-MM-dd-HH-mm</code>
* <td>Rollover at the beginning of every minute.</td>
* <td>At approximately 11:23,000, on March 9th, 2001, <code>/foo/bar.log</code> will be copied to
* <code>/foo/bar.log.2001-03-09-10-22</code>. Logging for the minute of 11:23 (9th of March) will be output to
* <code>/foo/bar.log</code> until it is rolled over the next minute. </table>
* 
* Do not use the colon ":" character in anywhere in the DatePattern option. The text before the colon is
* interpeted as the protocol specificaion of a URL which is probably not what you want.
* @author Eirik Lygre
* @author Ceki Gülcü
*/
public class AdvancedDailyRollingFileAppender extends FileAppender {

 // The code assumes that the following constants are in a increasing
 // sequence.
 static final int TOP_OF_TROUBLE = -1;
 static final int TOP_OF_MINUTE = 0;
 static final int TOP_OF_HOUR = 1;
 static final int HALF_DAY = 2;
 static final int TOP_OF_DAY = 3;
 static final int TOP_OF_WEEK = 4;
 static final int TOP_OF_MONTH = 5;

 /** Indicates if log files should be moved to archive file */
 private String compressBackups = "false";
 /** Indicates if archive file that may be created will be rolled off as it ages */
 private String rollCompressedBackups = "false";
 /** Maximum number of days to keep log files */
 private int maxNumberOfDays = 31;
 /** Number of days to wait before moving a log file to an archive */
 private int compressBackupsAfterDays = 31;
 /** Pattern used to name archive file (also controls what log files are grouped together */
 private String compressBackupsDatePattern = "'.'yyyy-MM";
 /** Maximum number of days to keep archive file before deleting */
 private int compressMaxNumberDays = 365;

 /**
 * The date pattern. By default, the pattern is set to "'.'yyyy-MM-dd" meaning daily rollover.
 */
 private String datePattern = "'.'yyyy-MM-dd";

 /**
 * The log file will be renamed to the value of the scheduledFilename variable when the next interval is entered.
 * For example, if the rollover period is one hour, the log file will be renamed to the value of "scheduledFilename"
 * at the beginning of the next hour. The precise time when a rollover occurs depends on logging activity.
 */
 private String scheduledFilename;

 /**
 * The next time we estimate a rollover should occur.
 */
 private long nextCheck = System.currentTimeMillis() - 1;

 Date now = new Date();

 SimpleDateFormat sdf;

 RollingCalendar rc = new RollingCalendar();

 int checkPeriod = TOP_OF_TROUBLE;

 // The gmtTimeZone is used only in computeCheckPeriod() method.
 static final TimeZone gmtTimeZone = TimeZone.getTimeZone("GMT");

 /**
 * The default constructor does nothing.
 */
 public AdvancedDailyRollingFileAppender() {
 }

 /**
 * Instantiate a <code>AdvancedDailyRollingFileAppender</code> and open the file designated by
 * <code>filename</code>. The opened filename will become the ouput destination for this appender.
 */
 public AdvancedDailyRollingFileAppender(Layout layout, String filename, String datePattern) throws IOException {
 super(layout, filename, true);
 this.datePattern = datePattern;
 activateOptions();
 }

 /**
 * The DatePattern takes a string in the same format as expected by {@link SimpleDateFormat}. This options
 * determines the rollover schedule.
 */
 public void setDatePattern(String pattern) {
 datePattern = pattern;
 }

 /** Returns the value of the DatePattern option. */
 public String getDatePattern() {
 return datePattern;
 }

 public String getCompressBackups() {
 return compressBackups;
 }

 public void setCompressBackups(String compressBackups) {
 this.compressBackups = compressBackups;
 }

 public String getMaxNumberOfDays() {
 return "" + maxNumberOfDays;
 }

 public void setMaxNumberOfDays(String days) {
 try {
 this.maxNumberOfDays = Integer.parseInt(days);
 } catch (Exception e) {
 // just leave it at default
 }

 }

 @Override
 public void activateOptions() {
 super.activateOptions();
 if (datePattern != null && fileName != null) {
 now.setTime(System.currentTimeMillis());
 sdf = new SimpleDateFormat(datePattern);
 int type = computeCheckPeriod();
 printPeriodicity(type);
 rc.setType(type);
 File file = new File(fileName);
 scheduledFilename = fileName + sdf.format(new Date(file.lastModified()));

 } else {
 LogLog.error("Either File or DatePattern options are not set for appender [" + name + "].");
 }
 }

 void printPeriodicity(int type) {
 switch (type) {
 case TOP_OF_MINUTE:
 LogLog.debug("Appender [" + name + "] to be rolled every minute.");
 break;
 case TOP_OF_HOUR:
 LogLog.debug("Appender [" + name + "] to be rolled on top of every hour.");
 break;
 case HALF_DAY:
 LogLog.debug("Appender [" + name + "] to be rolled at midday and midnight.");
 break;
 case TOP_OF_DAY:
 LogLog.debug("Appender [" + name + "] to be rolled at midnight.");
 break;
 case TOP_OF_WEEK:
 LogLog.debug("Appender [" + name + "] to be rolled at start of week.");
 break;
 case TOP_OF_MONTH:
 LogLog.debug("Appender [" + name + "] to be rolled at start of every month.");
 break;
 default:
 LogLog.warn("Unknown periodicity for appender [" + name + "].");
 }
 }

 // This method computes the roll over period by looping over the
 // periods, starting with the shortest, and stopping when the r0 is
 // different from from r1, where r0 is the epoch formatted according
 // the datePattern (supplied by the user) and r1 is the
 // epoch+nextMillis(i) formatted according to datePattern. All date
 // formatting is done in GMT and not local format because the test
 // logic is based on comparisons relative to 1970-01-01 00:00:00
 // GMT (the epoch).

 int computeCheckPeriod() {
 RollingCalendar rollingCalendar = new RollingCalendar(gmtTimeZone, Locale.getDefault());
 // set sate to 1970-01-01 00:00:00 GMT
 Date epoch = new Date(0);
 if (datePattern != null) {
 for (int i = TOP_OF_MINUTE; i <= TOP_OF_MONTH; i++) {
 SimpleDateFormat simpleDateFormat = new SimpleDateFormat(datePattern);
 simpleDateFormat.setTimeZone(gmtTimeZone); // do all date
 // formatting in GMT
 String r0 = simpleDateFormat.format(epoch);
 rollingCalendar.setType(i);
 Date next = new Date(rollingCalendar.getNextCheckMillis(epoch));
 String r1 = simpleDateFormat.format(next);
 // System.out.println("Type = "+i+", r0 = "+r0+", r1 = "+r1);
 if (r0 != null && r1 != null && !r0.equals(r1)) {
 return i;
 }
 }
 }
 return TOP_OF_TROUBLE; // Deliberately head for trouble...
 }

 /**
 * Rollover the current file to a new file.
 */
 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);
 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, true, this.bufferedIO, this.bufferSize);
 } catch (IOException e) {
 errorHandler.error("setFile(" + fileName + ", true) call failed.");
 }
 scheduledFilename = datedFilename;
 }

 /**
 * This method differentiates AdvancedDailyRollingFileAppender from its super class.
 * 
 * Before actually logging, this method will check whether it is time to do a rollover. If it is, it will schedule
 * the next rollover time and then rollover.
 */
 @Override
 protected void subAppend(LoggingEvent event) {
 long n = System.currentTimeMillis();
 if (n >= nextCheck) {
 now.setTime(n);
 nextCheck = rc.getNextCheckMillis(now);
 try {
 cleanupAndRollOver();
 } catch (IOException ioe) {
 if (ioe instanceof InterruptedIOException) {
 Thread.currentThread().interrupt();
 }
 LogLog.error("cleanupAndRollover() failed.", ioe);
 }
 }
 super.subAppend(event);
 }

 /*
 * This method checks to see if we're exceeding the number of log backups
 * that we are supposed to keep, and if so,
 * deletes the offending files. It then delegates to the rollover method to
 * rollover to a new file if required.
 */
 protected void cleanupAndRollOver() throws IOException {
 File file = new File(fileName);
 Calendar cal = Calendar.getInstance();

 cal.add(Calendar.DATE, -maxNumberOfDays);
 Date cutoffDate = cal.getTime();

 cal = Calendar.getInstance();
 cal.add(Calendar.DATE, -compressBackupsAfterDays);
 Date cutoffZip = cal.getTime();

 cal = Calendar.getInstance();
 cal.add(Calendar.DATE, -compressMaxNumberDays);
 Date cutoffDelZip = cal.getTime();

 if (file.getParentFile().exists()) {
 File[] files = file.getParentFile().listFiles(new StartsWithFileFilter(file.getName(), false));
 int nameLength = file.getName().length();
 for (int i = 0; i < files.length; i++) {
 String datePart = null;
 try {
 datePart = files[i].getName().substring(nameLength);
 Date date = sdf.parse(datePart);
 // cutoffDate for deletion should be further back than
 // cutoff for backup
 if (date.before(cutoffDate)) {
 files[i].delete();
 } else if (getCompressBackups().equalsIgnoreCase("YES")
 || getCompressBackups().equalsIgnoreCase("TRUE")) {
 if (date.before(cutoffZip)) {
 zipAndDelete(files[i], cutoffZip);
 }
 }
 } catch (ParseException pe) {
 // Ignore - bad parse format, not a log file, current log
 // file, or bad format on log file
 } catch (Exception e) {
 LogLog.warn("Failed to process file " + files[i].getName(), e);
 }
 try {
 if ((getRollCompressedBackups().equalsIgnoreCase("YES") || getRollCompressedBackups()
 .equalsIgnoreCase("TRUE"))
 && files[i].getName().endsWith(".zip")) {
 datePart = files[i].getName().substring(nameLength, files[i].getName().length() - 4);
 Date date = new SimpleDateFormat(compressBackupsDatePattern).parse(datePart);
 if (date.before(cutoffDelZip)) {
 files[i].delete();
 }
 }
 } catch (ParseException e) {
 // Ignore - parse exceptions mean that format is wrong or
 // there are other files in this dir
 } catch (Exception e) {
 LogLog.warn("Evaluating archive file for rolling failed: " + files[i].getName(), e);
 }
 }
 }
 rollOver();
 }

 /**
 * Compresses the passed file to a .zip file, stores the .zip in the same directory as the passed file, and then
 * deletes the original, leaving only the .zipped archive.
 * @param file
 */
 private void zipAndDelete(File file, Date cutoffZip) throws IOException {
 if (!file.getName().endsWith(".zip")) {
 String rootLogFileName = new File(fileName).getName();
 String datePart = file.getName().substring(rootLogFileName.length());
 String fileRoot = file.getName().substring(0, file.getName().indexOf(datePart));
 SimpleDateFormat sdf = new SimpleDateFormat(getCompressBackupsDatePattern());
 String newFile = fileRoot + sdf.format(cutoffZip);
 File zipFile = new File(file.getParent(), newFile + ".zip");

 if (zipFile.exists()) {
 addFilesToExistingZip(zipFile, new File[] { file });
 } else {

 FileInputStream fis = new FileInputStream(file);
 FileOutputStream fos = new FileOutputStream(zipFile);
 ZipOutputStream zos = new ZipOutputStream(fos);
 ZipEntry zipEntry = new ZipEntry(file.getName());
 zos.putNextEntry(zipEntry);

 byte[] buffer = new byte[4096];
 while (true) {
 int bytesRead = fis.read(buffer);
 if (bytesRead == -1)
 break;
 else {
 zos.write(buffer, 0, bytesRead);
 }
 }
 zos.closeEntry();
 fis.close();
 zos.close();
 }
 file.delete();
 }
 }

 /**
 * This is used to add files to a zip that already exits.
 * @param zipFile
 * @param files
 * @throws IOException
 */
 public static void addFilesToExistingZip(File zipFile, File[] files) throws IOException {
 // get a temp file
 File tempFile = File.createTempFile(zipFile.getName(), null);
 // delete it, otherwise you cannot rename your existing zip to it.
 tempFile.delete();

 boolean renameOk = zipFile.renameTo(tempFile);
 if (!renameOk) {
 throw new RuntimeException("could not rename the file " + zipFile.getAbsolutePath() + " to "
 + tempFile.getAbsolutePath());
 }
 byte[] buf = new byte[1024];

 ZipInputStream zin = new ZipInputStream(new FileInputStream(tempFile));
 ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipFile));

 ZipEntry entry = zin.getNextEntry();
 while (entry != null) {
 String name = entry.getName();
 boolean notInFiles = true;
 for (File f : files) {
 if (f.getName().equals(name)) {
 notInFiles = false;
 break;
 }
 }
 if (notInFiles) {
 // Add ZIP entry to output stream.
 out.putNextEntry(new ZipEntry(name));
 // Transfer bytes from the ZIP file to the output file
 int len;
 while ((len = zin.read(buf)) > 0) {
 out.write(buf, 0, len);
 }
 }
 entry = zin.getNextEntry();
 }
 // Close the streams
 zin.close();
 // Compress the files
 for (int i = 0; i < files.length; i++) {
 InputStream in = new FileInputStream(files[i]);
 // Add ZIP entry to output stream.
 out.putNextEntry(new ZipEntry(files[i].getName()));
 // Transfer bytes from the file to the ZIP file
 int len;
 while ((len = in.read(buf)) > 0) {
 out.write(buf, 0, len);
 }
 // Complete the entry
 out.closeEntry();
 in.close();
 }
 // Complete the ZIP file
 out.close();
 tempFile.delete();
 }

 public String getCompressBackupsAfterDays() {
 return "" + compressBackupsAfterDays;
 }

 public void setCompressBackupsAfterDays(String days) {
 try {
 compressBackupsAfterDays = Integer.parseInt(days);
 } catch (Exception e) {
 // ignore - just use default
 }
 }

 public String getCompressBackupsDatePattern() {
 return compressBackupsDatePattern;
 }

 public void setCompressBackupsDatePattern(String pattern) {
 compressBackupsDatePattern = pattern;
 }

 public String getCompressMaxNumberDays() {
 return compressMaxNumberDays + "";
 }

 public void setCompressMaxNumberDays(String days) {
 try {
 this.compressMaxNumberDays = Integer.parseInt(days);
 } catch (Exception e) {
 // ignore - just use default
 }
 }

 public String getRollCompressedBackups() {
 return rollCompressedBackups;
 }

 public void setRollCompressedBackups(String rollCompressedBackups) {
 this.rollCompressedBackups = rollCompressedBackups;
 }

}

class StartsWithFileFilter implements FileFilter {
 private String startsWith;
 private boolean inclDirs = false;

 /**
 *
 */
 public StartsWithFileFilter(String startsWith, boolean includeDirectories) {
 super();
 this.startsWith = startsWith.toUpperCase();
 inclDirs = includeDirectories;
 }

 /*
 * (non-Javadoc)
 * @see java.io.FileFilter#accept(java.io.File)
 */
 @Override
 public boolean accept(File pathname) {
 if (!inclDirs && pathname.isDirectory()) {
 return false;
 } else
 return pathname.getName().toUpperCase().startsWith(startsWith);
 }
}

/**
* RollingCalendar is a helper class to AdvancedDailyRollingFileAppender. Given a periodicity type and the current time,
* it computes the start of the next interval.
*/
class RollingCalendar extends GregorianCalendar {
 private static final long serialVersionUID = -3560331770601814177L;

 int type = AdvancedDailyRollingFileAppender.TOP_OF_TROUBLE;

 RollingCalendar() {
 super();
 }

 RollingCalendar(TimeZone tz, Locale locale) {
 super(tz, locale);
 }

 void setType(int type) {
 this.type = type;
 }

 public long getNextCheckMillis(Date now) {
 return getNextCheckDate(now).getTime();
 }

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

 switch (type) {
 case AdvancedDailyRollingFileAppender.TOP_OF_MINUTE:
 this.set(Calendar.SECOND, 0);
 this.set(Calendar.MILLISECOND, 0);
 this.add(Calendar.MINUTE, 1);
 break;
 case AdvancedDailyRollingFileAppender.TOP_OF_HOUR:
 this.set(Calendar.MINUTE, 0);
 this.set(Calendar.SECOND, 0);
 this.set(Calendar.MILLISECOND, 0);
 this.add(Calendar.HOUR_OF_DAY, 1);
 break;
 case AdvancedDailyRollingFileAppender.HALF_DAY:
 this.set(Calendar.MINUTE, 0);
 this.set(Calendar.SECOND, 0);
 this.set(Calendar.MILLISECOND, 0);
 int hour = get(Calendar.HOUR_OF_DAY);
 if (hour < 12) {
 this.set(Calendar.HOUR_OF_DAY, 12);
 } else {
 this.set(Calendar.HOUR_OF_DAY, 0);
 this.add(Calendar.DAY_OF_MONTH, 1);
 }
 break;
 case AdvancedDailyRollingFileAppender.TOP_OF_DAY:
 this.set(Calendar.HOUR_OF_DAY, 0);
 this.set(Calendar.MINUTE, 0);
 this.set(Calendar.SECOND, 0);
 this.set(Calendar.MILLISECOND, 0);
 this.add(Calendar.DATE, 1);
 break;
 case AdvancedDailyRollingFileAppender.TOP_OF_WEEK:
 this.set(Calendar.DAY_OF_WEEK, getFirstDayOfWeek());
 this.set(Calendar.HOUR_OF_DAY, 0);
 this.set(Calendar.MINUTE, 0);
 this.set(Calendar.SECOND, 0);
 this.set(Calendar.MILLISECOND, 0);
 this.add(Calendar.WEEK_OF_YEAR, 1);
 break;
 case AdvancedDailyRollingFileAppender.TOP_OF_MONTH:
 this.set(Calendar.DATE, 1);
 this.set(Calendar.HOUR_OF_DAY, 0);
 this.set(Calendar.MINUTE, 0);
 this.set(Calendar.SECOND, 0);
 this.set(Calendar.MILLISECOND, 0);
 this.add(Calendar.MONTH, 1);
 break;
 default:
 throw new IllegalStateException("Unknown periodicity type.");
 }
 return getTime();
 }
}

注:原作者的实现代码有两个bug: 如果设置7天, 结果只留下了6天的日志;另外一个就是在我的应用中发现删除文件的目录指定不对.另外一个就是删除只跟文件的名(比如这里的default.log)相关, 而跟生成的具体rotate log文件的格式(比如default.log.2012-01-12)是无关. 比如default.log.bak这样的文件也认为是7天文件中的一个.java-javascript 风之境地