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：
