期望结果：按日期生成文件夹，在最底层文件夹中记录日志，如：2019/03/11，在11这个文件夹下记录11号的日志，03和2019均为11的父文件夹。
API：log4j
主要步骤：继承log4j的org.apache.log4j.RollingFileAppender类，重写setFile、subAppend方法
配置文件：修改log4j的配置文件，将使用的类指向自己写的继承的类，改写日志文件目录格式
java代码：
import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import org.apache.log4j.RollingFileAppender;
import org.apache.log4j.helpers.CountingQuietWriter;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LoggingEvent;
//继承log4j的RollingFileAppender类
public class Log4jFileUpdate extends RollingFileAppender {
private long nextRollover = 0;
private static Map<String, BeginFileData> fileMaps = new HashMap<String, BeginFileData>();
private static final SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
public void rollOver () {
File target;
File file;
int maxBackupIndexLeng = String.valueOf(maxBackupIndex).length();
if (qw != null) {
long size = ((CountingQuietWriter) qw).getCount();
LogLog.debug("rolling over count=" + size);
nextRollover = size + maxFileSize;
}
LogLog.debug("maxBackupIndex=" + maxBackupIndex);
String nowDateString = sdf.format(new Date());
String newFileName = (fileName.indexOf(".") != -1 ? fileName.substring(0,
fileName.lastIndexOf(".")) : fileName);
boolean renameSucceeded = true;
if (maxBackupIndex > 0) {
file = new File(newFileName + '.' + nowDateString + '.'
+ getIndex(maxBackupIndex, maxBackupIndexLeng));
if (file.exists()) {
renameSucceeded = file.delete();
}
for (int i = maxBackupIndex - 1; (i >= 1 && renameSucceeded); i--) {
file = new File(newFileName + '.' + nowDateString + '.'
+ getIndex(i, maxBackupIndexLeng));
if (file.exists()) {
target = new File(newFileName + '.' + nowDateString + '.'
+ getIndex(i + 1, maxBackupIndexLeng));
LogLog.debug("Renaming file " + file + " to " + target);
renameSucceeded = file.renameTo(target);
}
}
if (renameSucceeded) {
BeginFileData beginFileData = fileMaps.get(fileName);
System.out.println("fileName= " + fileName + "\tbeginFileData="
+ beginFileData);
// 在每天一个日志目录的方式下，检测日期是否变更了，如果变更了就要把变更后的日志文件拷贝到变更后的日期目录下。
if (newFileName.indexOf(nowDateString) == -1
&& beginFileData.getFileName().indexOf("yyyy/MM/dd") != -1) {
newFileName = beginFileData.getFileName().replace("yyyy/MM/dd",
nowDateString);
newFileName = (newFileName.indexOf(".") != -1 ? newFileName
.substring(0, newFileName.lastIndexOf(".")) : newFileName);
}
target = new File(newFileName + '.' + nowDateString + '.'
+ getIndex(1, maxBackupIndexLeng));
this.closeFile();
file = new File(fileName);
LogLog.debug("Renaming file " + file + " to " + target);
renameSucceeded = file.renameTo(target);
if (!renameSucceeded) {
try {
this.setFile(fileName, true, bufferedIO, bufferSize);
} catch (IOException e) {
LogLog.error("setFile(" + fileName + ", true) call failed.", e);
}
}
}
}
//
// if all renames were successful, then
//
if (renameSucceeded) {
try {
this.setFile(fileName, false, bufferedIO, bufferSize);
nextRollover = 0;
} catch (IOException e) {
LogLog.error("setFile(" + fileName + ", false) call failed.", e);
}
}
}
/**
* 文件个数的长度补零，如果文件个数为10那么文件的个数长度就是2位，第一个文件就是01，02，03....
*
* @param i
* @param maxBackupIndexLeng
* @return
*/
private String getIndex (int i, int maxBackupIndexLeng) {
String index = String.valueOf(i);
int len = index.length();
for (int j = len; j < maxBackupIndexLeng; j++) {
index = "0" + index;
}
return index + ".log";
}
/**
* This method differentiates RollingFileAppender from its super class.
*
* @since 0.9.0
*/
protected void subAppend (LoggingEvent event) {
super.subAppend(event);
if (fileName != null && qw != null) {
String nowDate = sdf.format(new Date());
// 检测日期是否已经变更了，如果变更了就要重创建日期目录
if (!fileMaps.get(fileName).getDate().equals(nowDate)) {
rollOver();
return;
}
long size = ((CountingQuietWriter) qw).getCount();
if (size >= maxFileSize && size >= nextRollover) {
rollOver();
}
}
}
@Override
public synchronized void setFile (String fileName, boolean append,
boolean bufferedIO, int bufferSize) throws IOException {
String nowDate = sdf.format(new Date());
// 如果文件路径包含了“yyyy-MM-dd”就是每天一个日志目录的方式记录日志(第一次的时候)
if (fileName.indexOf("yyyy/MM/dd") != -1) {
String beginFileName = fileName;
fileName = fileName.replace("yyyy/MM/dd", nowDate);
fileMaps.put(fileName, new BeginFileData(beginFileName, nowDate));
}
BeginFileData beginFileData = fileMaps.get(fileName);
// 检测日期是否已经变更了，如果变更了就要把原始的字符串给fileName变量，把变更后的日期做为开始日期
if (!beginFileData.getDate().equals(nowDate)) {
// 获取出第一次的文件名
beginFileData.setDate(nowDate);
fileName = beginFileData.getFileName().replace("yyyy/MM/dd", nowDate);
fileMaps.put(fileName, beginFileData);
}
// D:/data/test/yyyy-MM-dd/test.log 替换yyyy-MM-dd为当前日期。
File file = new File(fileName);
File parentFile = file.getParentFile();
if (!parentFile.exists()) {
parentFile.mkdirs();
}
super.setFile(fileName, append, this.bufferedIO, this.bufferSize);
}
private class BeginFileData {
public BeginFileData (String fileName, String date) {
super();
this.fileName = fileName;
this.date = date;
}
private String fileName;
private String date;
public String getFileName () {
return fileName;
}
public void setFileName (String fileName) {
this.fileName = fileName;
}
public String getDate () {
return date;
}
public void setDate (String date) {
this.date = date;
}
}
}
log4j配置文件：
log4j.rootLogger=console,logErrFile,logfile
log4j.additivity.org.apache=true
log4j.logger.org.apache=off
log4j.logger.com.mchange=off
## (console)
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.Threshold=DUBUG
log4j.appender.console.ImmediateFlush=true
log4j.appender.console.Target=System.out
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss}:%p %t %c - %m%n
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern = %d{yyyy-MM-dd HH:mm:ss:SSS}:%p %t %l - %m%n
## (file: ERROR)
log4j.appender.logErrFile=util.Log4jFileUpdate
log4j.appender.logErrFile.Threshold=ERROR
log4j.appender.logErrFile.ImmediateFlush=true
log4j.appender.logErrFile.Append=true
log4j.appender.logErrFile.File=logger/yyyy/MM/dd/error_logs.log
log4j.appender.logErrFile.layout=org.apache.log4j.PatternLayout
log4j.appender.logErrFile.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss}:%p %t %c - %m%n
##log4j.appender.logErrFile.DatePattern =yyyyMMdd
log4j.appender.logfile=util.Log4jFileUpdate
log4j.appender.logfile.File=logger/yyyy/MM/dd/all.log
log4j.appender.logfile.MaxFileSize=10MB
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d{yyyy-MM-dd HH\:mm\:ss\:SSS}\: %p %t %l - %m%n效果：
附：
效果二：将java代码和配置文件中的yyyy/MM/dd改成yyyy-MM-dd即可
