如何让 log4j 删除旧的旋转日志文件？我知道我可以设置自动化作业（UNIX 的 cron 和 Windows 的计划任务），但我希望它跨平台，并且我希望它作为我们应用程序的一部分在我们的应用程序的日志配置中，而不是在操作系统外部的单独代码中特定的脚本语言。我们的应用程序不是用操作系统脚本语言编写的，我不想在其中做这部分。
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4 回答
58
RollingFileAppender做这个。您只需maxBackupIndex将备份文件设置为最高值。
于 2009-06-26T17:38:18.940 回答
46
日志轮换是有原因的，因此您只能保留这么多日志文件。在 log4j.xml 中，您可以将其添加到您的节点：
<param name="MaxBackupIndex" value="20"/>
该值告诉 log4j.xml 只保留 20 个旋转的日志文件。如果需要，您可以将其限制为 5 个，甚至 1 个。如果您的应用程序没有记录那么多数据，并且您在过去 8 个月中有 20 个日志文件，但您只需要一周的日志，那么我认为您需要调整您的 log4j.xml “MaxBackupIndex”和“MaxFileSize”参数。
或者，如果您使用的是属性文件（而不是 xml）并希望保存 15 个文件（例如）
log4j.appender.[appenderName].MaxBackupIndex = 15
于 2009-06-26T17:37:40.113 回答
11
没有默认值来控制删除 DailyRollingFileAppender 创建的旧日志文件。但是您可以编写自己的自定义 Appender 来删除旧日志文件，其方式与为 RollingFileAppender 设置 maxBackupIndex 的方式大致相同。
在这里找到简单的说明
从1开始：
如果您尝试将 Apache Log4J DailyRollingFileAppender 用于每日日志文件，您可能需要指定应保留的最大文件数。就像滚动 RollingFileAppender 支持 maxBackupIndex 一样。但是，如果您使用 DailyRollingFileAppender，当前版本的 Log4j（Apache log4j 1.2.16）不提供删除旧日志文件的任何机制。我尝试在 DailyRollingFileAppender 的原始版本中进行小修改以添加 maxBackupIndex 属性。因此，可以清理未来使用可能不需要的旧日志文件。
于 2014-05-01T19:08:17.823 回答
2
您可以使用自定义 log4j appender 来实现它。
MaxNumberOfDays - 可以设置轮换日志文件的天数。
CompressBackups - 可以使用 zip 扩展名归档旧日志。
package com.example.package;
import org.apache.log4j.FileAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LoggingEvent;
import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.Optional;
import java.util.TimeZone;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class CustomLog4jAppender extends FileAppender {
private static final int TOP_OF_TROUBLE = -1;
private static final int TOP_OF_MINUTE = 0;
private static final int TOP_OF_HOUR = 1;
private static final int HALF_DAY = 2;
private static final int TOP_OF_DAY = 3;
private static final int TOP_OF_WEEK = 4;
private static final int TOP_OF_MONTH = 5;
private String datePattern = "'.'yyyy-MM-dd";
private String compressBackups = "false";
private String maxNumberOfDays = "7";
private String scheduledFilename;
private long nextCheck = System.currentTimeMillis() - 1;
private Date now = new Date();
private SimpleDateFormat sdf;
private RollingCalendar rc = new RollingCalendar();
private static final TimeZone gmtTimeZone = TimeZone.getTimeZone("GMT");
public CustomLog4jAppender() {
}
public CustomLog4jAppender(Layout layout, String filename, String datePattern) throws IOException {
super(layout, filename, true);
this.datePattern = datePattern;
activateOptions();
}
public void setDatePattern(String pattern) {
datePattern = pattern;
}
public String getDatePattern() {
return datePattern;
}
@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 + "].");
}
}
private void printPeriodicity(int type) {
String appender = "Log4J Appender: ";
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 + "].");
}
}
private int computeCheckPeriod() {
RollingCalendar rollingCalendar = new RollingCalendar(gmtTimeZone, Locale.ENGLISH);
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);
String r0 = simpleDateFormat.format(epoch);
rollingCalendar.setType(i);
Date next = new Date(rollingCalendar.getNextCheckMillis(epoch));
String r1 = simpleDateFormat.format(next);
if (!r0.equals(r1)) {
return i;
}
}
}
return TOP_OF_TROUBLE;
}
private void rollOver() throws IOException {
if (datePattern == null) {
errorHandler.error("Missing DatePattern option in rollOver().");
return;
}
String datedFilename = fileName + sdf.format(now);
if (scheduledFilename.equals(datedFilename)) {
return;
}
this.closeFile();
File target = new File(scheduledFilename);
if (target.exists()) {
Files.delete(target.toPath());
}
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.setFile(fileName, false, this.bufferedIO, this.bufferSize);
} catch (IOException e) {
errorHandler.error("setFile(" + fileName + ", false) call failed.");
}
scheduledFilename = datedFilename;
}
@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) {
LogLog.error("cleanupAndRollover() failed.", ioe);
}
}
super.subAppend(event);
}
public String getCompressBackups() {
return compressBackups;
}
public void setCompressBackups(String compressBackups) {
this.compressBackups = compressBackups;
}
public String getMaxNumberOfDays() {
return maxNumberOfDays;
}
public void setMaxNumberOfDays(String maxNumberOfDays) {
this.maxNumberOfDays = maxNumberOfDays;
}
protected void cleanupAndRollOver() throws IOException {
File file = new File(fileName);
Calendar cal = Calendar.getInstance();
int maxDays = 7;
try {
maxDays = Integer.parseInt(getMaxNumberOfDays());
} catch (Exception e) {
// just leave it at 7.
}
cal.add(Calendar.DATE, -maxDays);
Date cutoffDate = cal.getTime();
if (file.getParentFile().exists()) {
File[] files = file.getParentFile().listFiles(new StartsWithFileFilter(file.getName(), false));
int nameLength = file.getName().length();
for (File value : Optional.ofNullable(files).orElse(new File[0])) {
String datePart;
try {
datePart = value.getName().substring(nameLength);
Date date = sdf.parse(datePart);
if (date.before(cutoffDate)) {
Files.delete(value.toPath());
} else if (getCompressBackups().equalsIgnoreCase("YES") || getCompressBackups().equalsIgnoreCase("TRUE")) {
zipAndDelete(value);
}
} catch (Exception pe) {
// This isn't a file we should touch (it isn't named correctly)
}
}
}
rollOver();
}
private void zipAndDelete(File file) throws IOException {
if (!file.getName().endsWith(".zip")) {
File zipFile = new File(file.getParent(), file.getName() + ".zip");
try (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();
}
Files.delete(file.toPath());
}
}
class StartsWithFileFilter implements FileFilter {
private String startsWith;
private boolean inclDirs;
StartsWithFileFilter(String startsWith, boolean includeDirectories) {
super();
this.startsWith = startsWith.toUpperCase();
inclDirs = includeDirectories;
}
public boolean accept(File pathname) {
if (!inclDirs && pathname.isDirectory()) {
return false;
} else {
return pathname.getName().toUpperCase().startsWith(startsWith);
}
}
}
class RollingCalendar extends GregorianCalendar {
private static final long serialVersionUID = -3560331770601814177L;
int type = CustomLog4jAppender.TOP_OF_TROUBLE;
RollingCalendar() {
super();
}
RollingCalendar(TimeZone tz, Locale locale) {
super(tz, locale);
}
void setType(int type) {
this.type = type;
}
long getNextCheckMillis(Date now) {
return getNextCheckDate(now).getTime();
}
Date getNextCheckDate(Date now) {
this.setTime(now);
switch (type) {
case CustomLog4jAppender.TOP_OF_MINUTE:
this.set(Calendar.SECOND, 0);
this.set(Calendar.MILLISECOND, 0);
this.add(Calendar.MINUTE, 1);
break;
case CustomLog4jAppender.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 CustomLog4jAppender.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 CustomLog4jAppender.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 CustomLog4jAppender.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 CustomLog4jAppender.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();
}
}
}
并在您的 log4j 配置文件中使用此属性：
log4j.appender.[appenderName]=com.example.package.CustomLog4jAppender
log4j.appender.[appenderName].File=/logs/app-daily.log
log4j.appender.[appenderName].Append=true
log4j.appender.[appenderName].encoding=UTF-8
log4j.appender.[appenderName].layout=org.apache.log4j.EnhancedPatternLayout
log4j.appender.[appenderName].layout.ConversionPattern=%-5.5p %d %C{1.} - %m%n
log4j.appender.[appenderName].DatePattern='.'yyyy-MM-dd
log4j.appender.[appenderName].MaxNumberOfDays=7
log4j.appender.[appenderName].CompressBackups=true
于 2019-11-06T11:57:58.373 回答