log4j 是否可以通过条件判断 在程序运行中动态选择日志存储目录

Question

比如我有两个用户A和B，我需要记录这两个用户的操作信息：add和del。

我希望把A的日志存放到logs/A/**目录下，比如
logs/A/add/add.log
logs/A/add/del.log

我希望把B的日志存放到logs/B/**目录下，比如
logs/B/add/add.log
logs/B/add/del.log

当程序在记录日志时,知道用户是谁。
如何在记录日志时，让程序根据用户来选择日志存放目录？

log4j支持这样的功能吗，能否给出简明的log4j配置。
在此谢谢各位~

Answer 1

可以的：
[code="java"]
package com.ljn.others;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;
import org.apache.log4j.RollingFileAppender;
import org.apache.log4j.varia.LevelRangeFilter;

/**

• @author lijinnan

• @date:2014-5-7
  */
  public class LoggerFactory {

  private static final String SEPARATOR = "/";
  private static final Map logMap = new HashMap();

  public static Logger getLogger(String baseDir, String userName,
  String fileName) {
  if (StringUtils.isEmpty(baseDir) || StringUtils.isEmpty(userName) || StringUtils.isEmpty(fileName)) {
  throw new IllegalArgumentException("cannot be empty");
  }
  String key = findKey(userName, fileName);
  Logger logger = logMap.get(key);
  if (logger == null)
  try {
  String logFilePath = baseDir + SEPARATOR + key;
  logger = Logger.getLogger(key);
  PatternLayout playout = new PatternLayout();
  playout.setConversionPattern("%d{[yyyy-MM-dd HH:mm:ss.SSS]}:[%p] %m%n");
  RollingFileAppender fAppender = new RollingFileAppender(playout, logFilePath);
  fAppender.setMaxFileSize("500MB");
  fAppender.setMaxBackupIndex(3);
  fAppender.setAppend(true);
  fAppender.setThreshold(Level.INFO);
  fAppender.setLayout(playout);
  LevelRangeFilter filterInfo = new LevelRangeFilter();
  filterInfo.setLevelMin(Level.INFO);
  filterInfo.setLevelMax(Level.ERROR);
  fAppender.addFilter(filterInfo);
  logger.addAppender(fAppender);
  logMap.put(key, logger);
  } catch (IOException e) {
  logger.error(Thread.currentThread().getName(), e);
  }
  return logger;
  }

  private static String findKey(String userName, String fileName) {
  return userName + SEPARATOR + fileName;
  }

}

package com.ljn.others;

import java.util.Random;

import org.apache.log4j.Logger;

/**

• @author lijinnan
  */
  public class UserService {

  private static final String BASE_DIR = "d:/odd/log";

  public static void main(String[] args) {
  while(true) {
  add();
  del();
  System.out.println("ok");
  }
  }

  public static void add() {
  String user = getCurrentUser();
  Logger logger = LoggerFactory.getLogger(BASE_DIR, user, "add.log");
  logger.info(user + " add");
  }

  public static void del() {
  String user = getCurrentUser();
  Logger logger = LoggerFactory.getLogger(BASE_DIR, user, "del.log");
  logger.info(user + " del");
  }

  private static String getCurrentUser() {
  Random random = new Random();
  int i = random.nextInt(10);
  if (i % 2 == 0) {
  return "A" ;
  }
  return "B";
  }
  }

[/code]