log4j1 修改FileAppender解决当天的文件没有日期后缀

直接上代码：

/*
 * 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 org.apache.log4j;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.Writer;

import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.helpers.QuietWriter;
import org.apache.log4j.spi.ErrorCode;

import reyo.sdk.utils.DateTimeUtils;
import reyo.sdk.utils.StringUtils;

// Contibutors: Jens Uwe Pipka <jens.pipka@gmx.de>
//              Ben Sandee

/**
 *  FileAppender appends log events to a file.
 *
 *  <p>Support for <code>java.io.Writer</code> and console appending
 *  has been deprecated and then removed. See the replacement
 *  solutions: {@link WriterAppender} and {@link ConsoleAppender}.
 *
 * @author Ceki Gülcü
 * */
public class FileAppender extends WriterAppender {

	/** Controls file truncatation. The default value for this variable
	 * is <code>true</code>, meaning that by default a
	 * <code>FileAppender</code> will append to an existing file and not
	 * truncate it.
	 *
	 * <p>This option is meaningful only if the FileAppender opens the
	 * file.
	 */
	protected boolean fileAppend = true;

	/**
	 The name of the log file. */
	protected String fileName = null;

	/**
	 Do we do bufferedIO? */
	protected boolean bufferedIO = false;

	/**
	 * Determines the size of IO buffer be. Default is 8K.
	 */
	protected int bufferSize = 8 * 1024;

	/**
	 The default constructor does not do anything.
	*/
	public FileAppender() {
	}

	/**
	Instantiate a <code>FileAppender</code> and open the file
	designated by <code>filename</code>. The opened filename will
	become the output destination for this appender.

	<p>If the <code>append</code> parameter is true, the file will be
	appended to. Otherwise, the file designated by
	<code>filename</code> will be truncated before being opened.

	<p>If the <code>bufferedIO</code> parameter is <code>true</code>,
	then buffered IO will be used to write to the output file.

	*/
	public FileAppender(Layout layout, String filename, boolean append, boolean bufferedIO, int bufferSize)
			throws IOException {
		this.layout = layout;
		this.setFile(filename, append, bufferedIO, bufferSize);
	}

	/**
	Instantiate a FileAppender and open the file designated by
	<code>filename</code>. The opened filename will become the output
	destination for this appender.

	<p>If the <code>append</code> parameter is true, the file will be
	appended to. Otherwise, the file designated by
	<code>filename</code> will be truncated before being opened.
	*/
	public FileAppender(Layout layout, String filename, boolean append) throws IOException {
		this.layout = layout;
		this.setFile(filename, append, false, bufferSize);
	}

	/**
	 Instantiate a FileAppender and open the file designated by
	<code>filename</code>. The opened filename will become the output
	destination for this appender.

	<p>The file will be appended to.  */
	public FileAppender(Layout layout, String filename) throws IOException {
		this(layout, filename, true);
	}

	/**
	 The <b>File</b> property takes a string value which should be the
	 name of the file to append to.

	 <p><font color="#DD0044"><b>Note that the special values
	 "System.out" or "System.err" are no longer honored.</b></font>

	 <p>Note: Actual opening of the file is made when {@link
	 #activateOptions} is called, not when the options are set.  */
	public void setFile(String file) {
		// Trim spaces from both ends. The users probably does not want
		// trailing spaces in file names.
		String val = file.trim();
		fileName = val;
	}

	/**
	  Returns the value of the <b>Append</b> option.
	 */
	public boolean getAppend() {
		return fileAppend;
	}

	/** Returns the value of the <b>File</b> option. */
	public String getFile() {
		return fileName;
	}

	/**
	 If the value of <b>File</b> is not <code>null</code>, then {@link
	 #setFile} is called with the values of <b>File</b>  and
	 <b>Append</b> properties.

	 @since 0.8.1 */
	@Override
	public void activateOptions() {

		String filetype = fileName.substring(fileName.lastIndexOf(".") + 1, fileName.length());
		if (StringUtils.isEmpty(filetype)) {
			fileName = fileName + DateTimeUtils.getCurrentDate() + ".log";
		}

		if (fileName != null) {
			try {
				setFile(fileName, fileAppend, bufferedIO, bufferSize);
			} catch (java.io.IOException e) {
				errorHandler.error("setFile(" + fileName + "," + fileAppend + ") call failed.", e,
						ErrorCode.FILE_OPEN_FAILURE);
			}
		} else {
			//LogLog.error("File option not set for appender ["+name+"].");
			LogLog.warn("File option not set for appender [" + name + "].");
			LogLog.warn("Are you using FileAppender instead of ConsoleAppender?");
		}
	}

	/**
	 Closes the previously opened file.
	 */
	protected void closeFile() {
		if (this.qw != null) {
			try {
				this.qw.close();
			} catch (java.io.IOException e) {
				if (e instanceof InterruptedIOException) {
					Thread.currentThread().interrupt();
				}
				// Exceptionally, it does not make sense to delegate to an
				// ErrorHandler. Since a closed appender is basically dead.
				LogLog.error("Could not close " + qw, e);
			}
		}
	}

	/**
	 Get the value of the <b>BufferedIO</b> option.

	 <p>BufferedIO will significatnly increase performance on heavily
	 loaded systems.

	*/
	public boolean getBufferedIO() {
		return this.bufferedIO;
	}

	/**
	 Get the size of the IO buffer.
	*/
	public int getBufferSize() {
		return this.bufferSize;
	}

	/**
	 The <b>Append</b> option takes a boolean value. It is set to
	 <code>true</code> by default. If true, then <code>File</code>
	 will be opened in append mode by {@link #setFile setFile} (see
	 above). Otherwise, {@link #setFile setFile} will open
	 <code>File</code> in truncate mode.

	 <p>Note: Actual opening of the file is made when {@link
	 #activateOptions} is called, not when the options are set.
	 */
	public void setAppend(boolean flag) {
		fileAppend = flag;
	}

	/**
	 The <b>BufferedIO</b> option takes a boolean value. It is set to
	 <code>false</code> by default. If true, then <code>File</code>
	 will be opened and the resulting {@link java.io.Writer} wrapped
	 around a {@link BufferedWriter}.

	 BufferedIO will significatnly increase performance on heavily
	 loaded systems.

	*/
	public void setBufferedIO(boolean bufferedIO) {
		this.bufferedIO = bufferedIO;
		if (bufferedIO) {
			immediateFlush = false;
		}
	}

	/**
	 Set the size of the IO buffer.
	*/
	public void setBufferSize(int bufferSize) {
		this.bufferSize = bufferSize;
	}

	/**
	<p>Sets and <i>opens</i> the file where the log output will
	go. The specified file must be writable.

	<p>If there was already an opened file, then the previous file
	is closed first.

	<p><b>Do not use this method directly. To configure a FileAppender
	or one of its subclasses, set its properties one by one and then
	call activateOptions.</b>

	@param fileName The path to the log file.
	@param append   If true will append to fileName. Otherwise will
	    truncate fileName.  */
	public synchronized void setFile(String fileName, boolean append, boolean bufferedIO, int bufferSize)
			throws IOException {
		LogLog.debug("setFile called: " + fileName + ", " + append);

		// It does not make sense to have immediate flush and bufferedIO.
		if (bufferedIO) {
			setImmediateFlush(false);
		}

		reset();
		FileOutputStream ostream = null;
		try {
			//
			//   attempt to create file
			//
			ostream = new FileOutputStream(fileName, append);
		} catch (FileNotFoundException ex) {
			//
			//   if parent directory does not exist then
			//      attempt to create it and try to create file
			//      see bug 9150
			//
			String parentName = new File(fileName).getParent();
			if (parentName != null) {
				File parentDir = new File(parentName);
				if (!parentDir.exists() && parentDir.mkdirs()) {
					ostream = new FileOutputStream(fileName, append);
				} else {
					throw ex;
				}
			} else {
				throw ex;
			}
		}
		Writer fw = createWriter(ostream);
		if (bufferedIO) {
			fw = new BufferedWriter(fw, bufferSize);
		}
		this.setQWForFiles(fw);
		this.fileName = fileName;
		this.fileAppend = append;
		this.bufferedIO = bufferedIO;
		this.bufferSize = bufferSize;
		writeHeader();
		LogLog.debug("setFile ended");
	}

	/**
	 Sets the quiet writer being used.

	 This method is overriden by {@link RollingFileAppender}.
	 */
	protected void setQWForFiles(Writer writer) {
		this.qw = new QuietWriter(writer, errorHandler);
	}

	/**
	 Close any previously opened file and call the parent's
	 <code>reset</code>.  */
	@Override
	protected void reset() {
		closeFile();
		this.fileName = null;
		super.reset();
	}
}

运行效果：