流程：
代码：
package com.han.log4jplugins;
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.Serializable;
import java.net.URI;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collections;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.List;
import java.util.Locale;
import java.util.TimeZone;
import org.apache.log4j.FileAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LoggingEvent;
/**
* @项目名称：log4jplugins
* @类名称：CustomDailyRollingFileAppender
* @类描述：DailyRollingFileAppender extends FileAppender</br>
* 重写RollingFileAppender类</br>
* 实现maxBackupIndex限制日志文件数量功能（定时删除超过N天前的日志文件）
*
* @UserGuid 分log4j.xml或log4j.properties两种情况：<br>
* 1）log4j.xml：设置<appender name="FILE" class="org.apache.log4j.RollingFileAppender">中的class属性为：com.han.log4jplugins.CustomDailyRollingFileAppender；<br>
* 2）log4j.properties：替换log4j.appender.debug=org.apache.log4j.RollingFileAppender中的RollingFileAppender，设置为com.han.log4jplugins.CustomDailyRollingFileAppender。
*
* @author HanZhijun
* @version V1.0.0
* @since 2018-03-01
*/
public class CustomDailyRollingFileAppender extends FileAppender {
// 初始化参数
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;
/**
* 生产日志文件后缀（"'.'yyyy-MM-dd"）
*/
private String datePattern = "'.'yyyy-MM-dd";
/**
* 默认：1个日志文件
*/
protected int maxBackupIndex = 1;
/**
* 保存前一天的日志文件名称 =filename+("'.'yyyy-MM-dd")
*/
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");
// 无参构造
public CustomDailyRollingFileAppender() {
}
/**
* 有参构造
* Instantiate a<code>DailyRollingFileAppender</code> and open the file designated by<code>filename</code>.
* The opened filename will become the ouput destination for thisappender.
*
* @param layout
* @param filename
*/
public CustomDailyRollingFileAppender(Layout layout, String filename, String datePattern) throws IOException {
super(layout, filename, true);
this.datePattern = datePattern;
activateOptions();
}
public void setDatePattern(String pattern) {
datePattern = pattern;
}
public void setMaxBackupIndex(int maxBackups) {
this.maxBackupIndex = maxBackups;
}
public int getMaxBackupIndex() {
return maxBackupIndex;
}
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("EitherFile 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("Unknownperiodicity 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...
}
/**
* 核心方法：生成日志文件，并完成对备份数量的监测以及历史日志的删除
* Rollover the current file to a new file.
*/
void rollOver() throws IOException {
// 获取所有日志历史文件：并完成对备份数量的监测以及历史日志的删除
List<ModifiedTimeSortableFile> files = getAllFiles();
Collections.sort(files);
// 如果文件数量不小于设置的最大备份数量，则启用日志删除策略
if (files.size() >= maxBackupIndex) {
int index = 0;
int diff = files.size() - (maxBackupIndex - 1);
for (ModifiedTimeSortableFile file : files) {
if (index >= diff)
break;
file.delete();
index++;
}
}
/* Compute filename, but only if datePattern is specified */
if (datePattern == null) {
errorHandler.error("MissingDatePattern option in rollOver().");
return;
}
LogLog.debug("maxBackupIndex=" + maxBackupIndex);
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("Failedto 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 differentiatesDailyRollingFileAppender from its super class.
* <p>
* Before actually logging, thismethod will check whether it is time to do a rollover. If it is,
* it willschedule 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 {
rollOver();
} catch (IOException ioe) {
if (ioe instanceof InterruptedIOException) {
Thread.currentThread().interrupt();
}
LogLog.error("rollOver()failed.", ioe);
}
}
super.subAppend(event);
}
/**
*
* 获取同一项目日志目录下所有文件
*
* This method searches list of log files
*
* based on the pattern given in the log4jconfiguration file
*
* and returns a collection
*
* @returnList<ModifiedTimeSortableFile>
*
*/
private List<ModifiedTimeSortableFile> getAllFiles() {
List<ModifiedTimeSortableFile> files = new ArrayList<ModifiedTimeSortableFile>();
FilenameFilter filter = new FilenameFilter() {
// 重写accept方法，确认是否是同一项目日志文件名称前缀。
@Override
public boolean accept(File dir, String name) {
String directoryName = dir.getPath();
LogLog.debug("directoryname: " + directoryName);
File file = new File(fileName);
String perentDirectory = file.getParent();
if (perentDirectory != null) {
// name=demo.log
// directoryName= /logs ，
// 直接fileName.substring(directoryName.length())；切割之后的localFile=/demo.log…，会导致name.startsWith(localFile)始终是false
// so解决方案：长度 +1
String localFile = fileName.substring(directoryName.length() + 1);
return name.startsWith(localFile);
}
return name.startsWith(fileName);
}
};
File file = new File(fileName);
String perentDirectory = file.getParent();
if (file.exists()) {
if (file.getParent() == null) {
String absolutePath = file.getAbsolutePath();
perentDirectory = absolutePath.substring(0, absolutePath.lastIndexOf(fileName));
}
}
File dir = new File(perentDirectory);
String[] names = dir.list(filter);
for (int i = 0; i < names.length; i++) {
files.add(new ModifiedTimeSortableFile(dir + System.getProperty("file.separator") + names[i]));
}
return files;
}
}
/**
* 自定义file类，重写compareTo方法，比较文件的修改时间
*
* The ClassModifiedTimeSortableFile extends java.io.File class and
*
* implements Comparable to sortfiles list based upon their modified date
*
*/
class ModifiedTimeSortableFile extends File implements Serializable, Comparable<File> {
private static final long serialVersionUID = 1373373728209668895L;
public ModifiedTimeSortableFile(String parent, String child) {
super(parent, child);
}
public ModifiedTimeSortableFile(URI uri) {
super(uri);
}
public ModifiedTimeSortableFile(File parent, String child) {
super(parent, child);
}
public ModifiedTimeSortableFile(String string) {
super(string);
}
@Override
public int compareTo(File anotherPathName) {
long thisVal = this.lastModified();
long anotherVal = anotherPathName.lastModified();
return (thisVal < anotherVal ? -1 : (thisVal == anotherVal ? 0 : 1));
}
}
/**
*
* RollingCalendar is a helper class toDailyRollingFileAppender.
*
* Given a periodicity type and the currenttime, it computes the
*
* start of the next interval.
*
*/
class RollingCalendar extends GregorianCalendar {
private static final long serialVersionUID = -8295691444111406775L;
int type = CustomDailyRollingFileAppender.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 CustomDailyRollingFileAppender.TOP_OF_MINUTE:
this.set(Calendar.SECOND, 0);
this.set(Calendar.MILLISECOND, 0);
this.add(Calendar.MINUTE, 1);
break;
case CustomDailyRollingFileAppender.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 CustomDailyRollingFileAppender.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 CustomDailyRollingFileAppender.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 CustomDailyRollingFileAppender.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 CustomDailyRollingFileAppender.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();
}
}
对应的log4j配置文件的设置：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd" >
<log4j:configuration>
<!-- 引用自定义的CustomDailyRollingFileAppender日志类 -->
<appender name="FILE" class="com.han.log4jplugins.CustomDailyRollingFileAppender">
<!-- 自定义日志输出路径和名称 -->
<param name="file" value="D:/logs/test-agent.log"/>
<!-- 自定义历史日志文件后缀名 -->
<param name="datePattern" value="'.'yyyy-MM-dd"/>
<!-- 自定义日志文件总数量，大于这个数量，自动删除 -->
<param name="maxBackupIndex" value="1"/>
<param name="append" value="true"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d [%t] %p - %m%n"/>
</layout>
</appender>
<appender name="stdout" class="org.apache.log4j.ConsoleAppender">
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss,SSS} %p [%c-%M-%L]:%m%n" />
</layout>
</appender>
<root>
<priority value="info"/>
<appender-ref ref="FILE"/>
<appender-ref ref="stdout"/>
</root>
</log4j:configuration>
功能测试类：
package com.han.log4jplugins;
import java.io.File;
import java.net.URL;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
/**
* 自定义每天日志文件生成策略的测试类
*
* @author HanZhijun
* @version V1.0.0
* @since 2018-03-01
*/
public class CustomDailyRollingFileAppenderTest {
private static Logger logger = Logger.getLogger(CustomDailyRollingFileAppenderTest.class);
public static void main(String[] args) {
String configFile = "log4j.xml";
final File file = new File(configFile);
if(!file.exists()) {
final URL url = CustomDailyRollingFileAppenderTest.class.getClassLoader().getResource("log4j.xml");
configFile = url.getPath();
}
PropertyConfigurator.configure(configFile);
logger.info("11111");
}
}