日志文件自动删除功能必不可少，当然你可以让运维去做这事，只是这不地道。而日志组件是一个必备组件，让其多做一件删除的工作，无可厚非。本文就来探讨下 log4j 的日志文件自动删除实现吧。

0.自动删除配置参考样例: （log4j2.xml）

<?xml version="1.0" encoding="UTF-8" ?><Configuration status="warn" monitorInterval="30" strict="true" schema="Log4J-V2.2.xsd"> <Properties> <Property name="log_level">info</Property> </Properties> <Appenders> <!-- 输出到控制台 --> <Console name="Console" target="SYSTEM_OUT"> <ThresholdFilter level="${log_level}" onMatch="ACCEPT" onMismatch="DENY" /> <PatternLayout pattern="%d{yyyy-MM-dd'T'HH:mm:ss.SSS} [%t] %p - %c - %m%n" /> </Console> <!-- 与properties文件中位置存在冲突，如有问题，请注意调整 --> <RollingFile name="logFile" fileName="logs/app/test.log" filePattern="logs/app/history/test-%d{MM-dd-yyyy}-%i.log.gz"> <ThresholdFilter level="${log_level}" onMatch="ACCEPT" onMismatch="DENY" /> <PatternLayout pattern="%d{yyyy-MM-dd'T'HH:mm:ss.SSS} [%p] [%c:%L] -- %m%n" /> <Policies> <!-- 按天递计算频率 --> <TimeBasedTriggeringPolicy interval="1" /> <SizeBasedTriggeringPolicy size="500 MB" /> <OnStartupTriggeringPolicy /> </Policies> <!-- 删除策略配置 --> <DefaultRolloverStrategy max="5"> <Delete basePath="logs/app/history" maxDepth="1"> <IfFileName glob="*.log.gz"/> <IfLastModified age="7d"/> </Delete> <Delete basePath="logs/app/history" maxDepth="1"> <IfFileName glob="*.docx"/> </Delete> <Delete basePath="logs/app/history" maxDepth="1"> <IfFileName glob="*.vsdx"/> </Delete> </DefaultRolloverStrategy> </RollingFile> <Async name="Async" bufferSize="2000" blocking="false"> <AppenderRef ref="logFile"/> </Async> </Appenders> <Loggers> <Root level="${log_level}"> <AppenderRef ref="Console" /> <AppenderRef ref="Async" /> </Root> <!-- 配置个例 --> <Logger name="com.xx.filter" level="info" /> </Loggers></Configuration>

　　如果仅想停留在使用层面，如上log4j2.xml配置文件足矣！

　　不过，至少得注意一点，以上配置需要基于log4j2, 而如果你是 log4j1.x,则需要做下无缝升级：主要就是换下jar包版本，换个桥接包之类的,比如下参考配置：

<dependency> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> <version>1.2</version> </dependency> <!-- 桥接：告诉commons logging使用Log4j2 --> <dependency> <groupId>org.slf4j</groupId> <artifactId>jcl-over-slf4j</artifactId> <version>1.7.26</version> </dependency> <!-- 此处老版本，需注释掉 --> <!--<dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency>--> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-compress</artifactId> <version>1.10</version> </dependency> <dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-core</artifactId> <version>2.8.2</version> </dependency> <dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-slf4j-impl</artifactId> <version>2.8.2</version> </dependency> <dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-api</artifactId> <version>2.8.2</version> </dependency> <dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-web</artifactId> <version>2.8.2</version> </dependency>

　如果还想多了解一点其运行原理，就跟随本文的脚步吧:

1.自动清理大体运行流程

　　自动删除工作的运行原理大体流程如下。（大抵都是如此）

　　　　1. 加载log4j2.xml配置文件;
　　　　2. 读取appenders，并添加到log4j上下文中;
　　　　3. 加载 policy, 加载 rollover 配置;
　　　　4. 写入日志时判断是否满足rollover配置, 默认是一天运行一次, 可自行添加各种运行测试, 比如大小、启动时;

　　所以，删除策略的核心是每一次添加日志时。代码验证如下：

// 在每次添加日志时判定 // org.apache.logging.log4j.core.appender.RollingRandomAccessFileAppender#append /** * Write the log entry rolling over the file when required. * * @param event The LogEvent. */ @Override public void append(final LogEvent event) { final RollingRandomAccessFileManager manager = getManager(); // 重点：直接检查是否需要 rollover, 如需要直接进行 manager.checkRollover(event); // Leverage the nice batching behaviour of async Loggers/Appenders: // we can signal the file manager that it needs to flush the buffer // to disk at the end of a batch. // From a user's point of view, this means that all log events are // _always_ available in the log file, without incurring the overhead // of immediateFlush=true. manager.setEndOfBatch(event.isEndOfBatch()); // FIXME manager's EndOfBatch threadlocal can be deleted // LOG4J2-1292 utilize gc-free Layout.encode() method: taken care of in superclass super.append(event); } // org.apache.logging.log4j.core.appender.rolling.RollingFileManager#checkRollover /** * Determines if a rollover should occur. * @param event The LogEvent. */ public synchronized void checkRollover(final LogEvent event) { // 由各触发策略判定是否需要进行 rolling // 如需要, 则调用 rollover() if (triggeringPolicy.isTriggeringEvent(event)) { rollover(); } }

　　所以，何时进行删除？答案是在适当的时机，这个时机可以是任意时候。

2. log4j 日志滚动

　　日志滚动，可以是重命名，也可以是删除文件。但总体判断是否可触发滚动的前提是一致的。我们这里主要关注文件删除。我们以时间作为依据看下判断过程。

// 1. 判断是否是 触发事件时机 // org.apache.logging.log4j.core.appender.rolling.TimeBasedTriggeringPolicy#isTriggeringEvent /** * Determines whether a rollover should occur. * @param event A reference to the currently event. * @return true if a rollover should occur. */ @Override public boolean isTriggeringEvent(final LogEvent event) { if (manager.getFileSize() == 0) { return false; } final long nowMillis = event.getTimeMillis(); // TimeBasedTriggeringPolicy, 是基于时间判断的, 此处为每天一次 if (nowMillis >= nextRolloverMillis) { nextRolloverMillis = manager.getPatternProcessor().getNextTime(nowMillis, interval, modulate); return true; } return false; } // org.apache.logging.log4j.core.appender.rolling.RollingFileManager#rollover() public synchronized void rollover() { if (!hasOutputStream()) { return; } // strategy 是xml配置的策略 if (rollover(rolloverStrategy)) { try { size = 0; initialTime = System.currentTimeMillis(); createFileAfterRollover(); } catch (final IOException e) { logError("Failed to create file after rollover", e); } } } // RollingFileManager 统一管理触发器 // org.apache.logging.log4j.core.appender.rolling.RollingFileManager#rollover private boolean rollover(final RolloverStrategy strategy) { boolean releaseRequired = false; try { // Block until the asynchronous operation is completed. // 上锁保证线程安全 semaphore.acquire(); releaseRequired = true; } catch (final InterruptedException e) { logError("Thread interrupted while attempting to check rollover", e); return false; } boolean success = true; try { // 由各触发器运行 rollover 逻辑 final RolloverDescription descriptor = strategy.rollover(this); if (descriptor != null) { writeFooter(); closeOutputStream(); if (descriptor.getSynchronous() != null) { LOGGER.debug("RollingFileManager executing synchronous {}", descriptor.getSynchronous()); try { // 先使用同步方法，改名，然后再使用异步方法操作更多 success = descriptor.getSynchronous().execute(); } catch (final Exception ex) { success = false; logError("Caught error in synchronous task", ex); } } // 如果配置了异步器, 则使用异步进行 rollover if (success && descriptor.getAsynchronous() != null) { LOGGER.debug("RollingFileManager executing async {}", descriptor.getAsynchronous()); // CompositeAction, 使用异步线程池运行用户的 action asyncExecutor.execute(new AsyncAction(descriptor.getAsynchronous(), this)); // 在异步运行action期间，锁是不会被释放的，以避免线程安全问题 // 直到异步任务完成，再主动释放锁 releaseRequired = false; } return true; } return false; } finally { if (releaseRequired) { semaphore.release(); } } }

　　此处滚动有两个处理点，1. 每个滚动策略可以自行处理业务； 2. RollingFileManager 统一管理触发同步和异步的滚动action；

3. DefaultRolloverStrategy 默认滚动策略驱动

　　DefaultRolloverStrategy 作为一个默认的滚动策略实现，可以配置多个 Action, 然后处理删除操作。

　　删除有两种方式: 1. 当次滚动的文件数过多，会立即进行删除; 2. 配置单独的 DeleteAction, 根据配置的具体策略进行删除。（但该Action只会被返回给外部调用，自身则不会执行）

// org.apache.logging.log4j.core.appender.rolling.DefaultRolloverStrategy#rollover /** * Performs the rollover. * * @param manager The RollingFileManager name for current active log file. * @return A RolloverDescription. * @throws SecurityException if an error occurs. */ @Override public RolloverDescription rollover(final RollingFileManager manager) throws SecurityException { int fileIndex; // 默认 minIndex=1 if (minIndex == Integer.MIN_VALUE) { final SortedMap<Integer, Path> eligibleFiles = getEligibleFiles(manager); fileIndex = eligibleFiles.size() > 0 ? eligibleFiles.lastKey() + 1 : 1; } else { if (maxIndex < 0) { return null; } final long startNanos = System.nanoTime(); // 删除case1: 获取符合条件的文件数，同时清理掉大于 max 配置的日志文件 // 如配置 max=5, 当前只有4个满足时, 不会立即清理文件, 但也不会阻塞后续流程 // 只要没有出现错误, fileIndex 不会小于0 fileIndex = purge(minIndex, maxIndex, manager); if (fileIndex < 0) { return null; } if (LOGGER.isTraceEnabled()) { final double durationMillis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos); LOGGER.trace("DefaultRolloverStrategy.purge() took {} milliseconds", durationMillis); } } // 进入此区域即意味着，必然有文件需要滚动，重新命名了 final StringBuilder buf = new StringBuilder(255); manager.getPatternProcessor().formatFileName(strSubstitutor, buf, fileIndex); final String currentFileName = manager.getFileName(); String renameTo = buf.toString(); final String compressedName = renameTo; Action compressAction = null; FileExtension fileExtension = manager.getFileExtension(); if (fileExtension != null) { renameTo = renameTo.substring(0, renameTo.length() - fileExtension.length()); compressAction = fileExtension.createCompressAction(renameTo, compressedName, true, compressionLevel); } // 未发生文件重命名情况，即文件未被重命名未被滚动 // 该种情况应该不太会发生 if (currentFileName.equals(renameTo)) { LOGGER.warn("Attempt to rename file {} to itself will be ignored", currentFileName); return new RolloverDescriptionImpl(currentFileName, false, null, null); } // 新建一个重命令的 action, 返回待用 final FileRenameAction renameAction = new FileRenameAction(new File(currentFileName), new File(renameTo), manager.isRenameEmptyFiles()); // 异步处理器，会处理用户配置的异步action，如本文配置的 DeleteAction // 它将会在稍后被提交到异步线程池中运行 final Action asyncAction = merge(compressAction, customActions, stopCustomActionsOnError); // 封装Rollover返回, renameAction 是同步方法, 其他用户配置的动态action 则是异步方法 // 删除case2: 封装异步返回action return new RolloverDescriptionImpl(currentFileName, false, renameAction, asyncAction); } private int purge(final int lowIndex, final int highIndex, final RollingFileManager manager) { // 默认使用 accending 的方式进行清理文件 return useMax ? purgeAscending(lowIndex, highIndex, manager) : purgeDescending(lowIndex, highIndex, manager); } // org.apache.logging.log4j.core.appender.rolling.DefaultRolloverStrategy#purgeAscending /** * Purges and renames old log files in preparation for rollover. The oldest file will have the smallest index, the * newest the highest. * * @param lowIndex low index. Log file associated with low index will be deleted if needed. * @param highIndex high index. * @param manager The RollingFileManager * @return true if purge was successful and rollover should be attempted. */ private int purgeAscending(final int lowIndex, final int highIndex, final RollingFileManager manager) { final SortedMap<Integer, Path> eligibleFiles = getEligibleFiles(manager); final int maxFiles = highIndex - lowIndex + 1; boolean renameFiles = false; // 依次迭代 eligibleFiles, 删除 while (eligibleFiles.size() >= maxFiles) { try { LOGGER.debug("Eligible files: {}", eligibleFiles); Integer key = eligibleFiles.firstKey(); LOGGER.debug("Deleting {}", eligibleFiles.get(key).toFile().getAbsolutePath()); // 调用nio的接口删除文件 Files.delete(eligibleFiles.get(key)); eligibleFiles.remove(key); renameFiles = true; } catch (IOException ioe) { LOGGER.error("Unable to delete {}, {}", eligibleFiles.firstKey(), ioe.getMessage(), ioe); break; } } final StringBuilder buf = new StringBuilder(); if (renameFiles) { // 针对未完成删除的文件，继续处理 // 比如使用 匹配的方式匹配文件, 则不能被正常删除 // 还有些未超过maxFiles的文件 for (Map.Entry<Integer, Path> entry : eligibleFiles.entrySet()) { buf.setLength(0); // LOG4J2-531: directory scan & rollover must use same format manager.getPatternProcessor().formatFileName(strSubstitutor, buf, entry.getKey() - 1); String currentName = entry.getValue().toFile().getName(); String renameTo = buf.toString(); int suffixLength = suffixLength(renameTo); if (suffixLength > 0 && suffixLength(currentName) == 0) { renameTo = renameTo.substring(0, renameTo.length() - suffixLength); } Action action = new FileRenameAction(entry.getValue().toFile(), new File(renameTo), true); try { LOGGER.debug("DefaultRolloverStrategy.purgeAscending executing {}", action); if (!action.execute()) { return -1; } } catch (final Exception ex) { LOGGER.warn("Exception during purge in RollingFileAppender", ex); return -1; } } } // 此处返回的 findIndex 一定是 >=0 的 return eligibleFiles.size() > 0 ? (eligibleFiles.lastKey() < highIndex ? eligibleFiles.lastKey() + 1 : highIndex) : lowIndex; }

4. 符合过滤条件的文件查找

　　当配置了 max 参数，这个参数是如何匹配的呢？比如我某个文件夹下有很历史文件，是否都会匹配呢？

// 文件查找规则 // org.apache.logging.log4j.core.appender.rolling.AbstractRolloverStrategy#getEligibleFiles protected SortedMap<Integer, Path> getEligibleFiles(final RollingFileManager manager) { return getEligibleFiles(manager, true); } protected SortedMap<Integer, Path> getEligibleFiles(final RollingFileManager manager, final boolean isAscending) { final StringBuilder buf = new StringBuilder(); // 此处的pattern 即是在appender上配置的 filePattern, 一般会受限于 MM-dd-yyyy-$i.log.gz String pattern = manager.getPatternProcessor().getPattern(); // 此处会将时间替换为当前, 然后按照此规则进行匹配要处理的文件 manager.getPatternProcessor().formatFileName(strSubstitutor, buf, NotANumber.NAN); return getEligibleFiles(buf.toString(), pattern, isAscending); } // 细节匹配要处理的文件 protected SortedMap<Integer, Path> getEligibleFiles(String path, String logfilePattern, boolean isAscending) { TreeMap<Integer, Path> eligibleFiles = new TreeMap<>(); File file = new File(path); File parent = file.getParentFile(); if (parent == null) { parent = new File("."); } else { parent.mkdirs(); } if (!logfilePattern.contains("%i")) { return eligibleFiles; } Path dir = parent.toPath(); String fileName = file.getName(); int suffixLength = suffixLength(fileName); if (suffixLength > 0) { fileName = fileName.substring(0, fileName.length() - suffixLength) + ".*"; } String filePattern = fileName.replace(NotANumber.VALUE, "(\\d+)"); Pattern pattern = Pattern.compile(filePattern); try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) { for (Path entry: stream) { // 该匹配相当精确 // 只会删除当天或者在时间交替的时候删除上一天的数据咯 // 如果在这个时候进行了重启操作，就再也不会删除此文件了 Matcher matcher = pattern.matcher(entry.toFile().getName()); if (matcher.matches()) { Integer index = Integer.parseInt(matcher.group(1)); eligibleFiles.put(index, entry); } } } catch (IOException ioe) { throw new LoggingException("Error reading folder " + dir + " " + ioe.getMessage(), ioe); } return isAscending? eligibleFiles : eligibleFiles.descendingMap(); } // 此处会将 各种格式的文件名，替换为当前时间或者最后一次滚动的文件的时间。所以匹配的时候，并不会匹配超时当前认知范围的文件 /** * Formats file name. * @param subst The StrSubstitutor. * @param buf string buffer to which formatted file name is appended, may not be null. * @param obj object to be evaluated in formatting, may not be null. */ public final void formatFileName(final StrSubstitutor subst, final StringBuilder buf, final boolean useCurrentTime, final Object obj) { // LOG4J2-628: we deliberately use System time, not the log4j.Clock time // for creating the file name of rolled-over files. final long time = useCurrentTime && currentFileTime != 0 ? currentFileTime : prevFileTime != 0 ? prevFileTime : System.currentTimeMillis(); formatFileName(buf, new Date(time), obj); final LogEvent event = new Log4jLogEvent.Builder().setTimeMillis(time).build(); final String fileName = subst.replace(event, buf); buf.setLength(0); buf.append(fileName); }

　　AsyncAction 是一个 Runnable 的实现, 被直接提交到线程池运行. AsyncAction -> AbstractAction -> Action -> Runnable

　　它是一个统一管理异步Action的包装，主要是管理锁和异常类操作。

// org.apache.logging.log4j.core.appender.rolling.RollingFileManager.AsyncAction /** * Performs actions asynchronously. */ private static class AsyncAction extends AbstractAction { private final Action action; private final RollingFileManager manager; /** * Constructor. * @param act The action to perform. * @param manager The manager. */ public AsyncAction(final Action act, final RollingFileManager manager) { this.action = act; this.manager = manager; } /** * Executes an action. * * @return true if action was successful. A return value of false will cause * the rollover to be aborted if possible. * @throws java.io.IOException if IO error, a thrown exception will cause the rollover * to be aborted if possible. */ @Override public boolean execute() throws IOException { try { // 门面调用 action.execute(), 一般是调用 CompositeAction, 里面封装了多个 action return action.execute(); } finally { // 任务执行完成，才会释放外部的锁 // 虽然不是很优雅，但是很准确很安全 manager.semaphore.release(); } } ... } // CompositeAction 封装了多个 action 处理 // org.apache.logging.log4j.core.appender.rolling.action.CompositeAction#run /** * Execute sequence of actions. * * @return true if all actions were successful. * @throws IOException on IO error. */ @Override public boolean execute() throws IOException { if (stopOnError) { // 依次调用action for (final Action action : actions) { if (!action.execute()) { return false; } } return true; } boolean status = true; IOException exception = null; for (final Action action : actions) { try { status &= action.execute(); } catch (final IOException ex) { status = false; if (exception == null) { exception = ex; } } } if (exception != null) { throw exception; } return status; }

　　DeleteAction是我们真正关心的动作。

// CompositeAction 封装了多个 action 处理 // org.apache.logging.log4j.core.appender.rolling.action.CompositeAction#run /** * Execute sequence of actions. * * @return true if all actions were successful. * @throws IOException on IO error. */ @Override public boolean execute() throws IOException { if (stopOnError) { // 依次调用action for (final Action action : actions) { if (!action.execute()) { return false; } } return true; } boolean status = true; IOException exception = null; for (final Action action : actions) { try { status &= action.execute(); } catch (final IOException ex) { status = false; if (exception == null) { exception = ex; } } } if (exception != null) { throw exception; } return status; } // DeleteAction 做真正的删除动作 // org.apache.logging.log4j.core.appender.rolling.action.DeleteAction#execute() @Override public boolean execute() throws IOException { // 如果没有script配置，则直接委托父类处理 return scriptCondition != null ? executeScript() : super.execute(); } org.apache.logging.log4j.core.appender.rolling.action.AbstractPathAction#execute() @Override public boolean execute() throws IOException { // 根据指定的basePath, 和过滤条件，选择相关文件 // 调用 DeleteAction 的 createFileVisitor(), 返回 DeletingVisitor return execute(createFileVisitor(getBasePath(), pathConditions)); } // org.apache.logging.log4j.core.appender.rolling.action.DeleteAction#execute(java.nio.file.FileVisitor<java.nio.file.Path>) @Override public boolean execute(final FileVisitor<Path> visitor) throws IOException { // 根据maxDepth设置，遍历所有可能的文件路径 // 使用 Files.walkFileTree() 实现, 添加到 collected 中 final List<PathWithAttributes> sortedPaths = getSortedPaths(); trace("Sorted paths:", sortedPaths); for (final PathWithAttributes element : sortedPaths) { try { // 依次调用 visitFile, 依次判断是否需要删除 visitor.visitFile(element.getPath(), element.getAttributes()); } catch (final IOException ioex) { LOGGER.error("Error in post-rollover Delete when visiting {}", element.getPath(), ioex); visitor.visitFileFailed(element.getPath(), ioex); } } // TODO return (visitor.success || ignoreProcessingFailure) return true; // do not abort rollover even if processing failed }

　　最终，即和想像的一样：找到要查找的文件夹，遍历各文件，用多个条件判断是否满足。删除符合条件的文件。

　　只是这其中注意的点：如何删除文件的线程安全性；如何保证删除工作不影响业务线程；很常见的锁和多线程的应用。

5.真正的删除

　　真正的删除动作就是在DeleteAction中配置的，但上面可以看它是调用visitor的visitFile方法，所以有必要看看是如何真正处理删除的。（实际上前面在purge时已经做过一次删除操作了，所以别被两个点迷惑了，建议尽量只依赖于Delete配置，可以将外部max设置很大以避免两处生效）

// org.apache.logging.log4j.core.appender.rolling.action.DeletingVisitor#visitFile @Override public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs) throws IOException { for (final PathCondition pathFilter : pathConditions) { final Path relative = basePath.relativize(file); // 遍历所有条件，只要有一个不符合，即不进行删除。 // 所以，所以条件是 AND 关系， 没有 OR 关系 // 如果想配置 OR 关系，只能配置多个DELETE if (!pathFilter.accept(basePath, relative, attrs)) { LOGGER.trace("Not deleting base={}, relative={}", basePath, relative); return FileVisitResult.CONTINUE; } } // 直接删除文件 if (isTestMode()) { LOGGER.info("Deleting {} (TEST MODE: file not actually deleted)", file); } else { delete(file); } return FileVisitResult.CONTINUE; }

　　删除策略配置比如:

<RollingFile name="logFile" fileName="logs/app/test.log" filePattern="logs/app/history/test-%d{MM-dd-yyyy}-%i.log.gz"> <ThresholdFilter level="${log_level}" onMatch="ACCEPT" onMismatch="DENY" /> <PatternLayout pattern="%d{yyyy-MM-dd'T'HH:mm:ss.SSS} [%p] [%c:%L] -- %m%n" /> <Policies> <!-- 按天递计算频率 --> <TimeBasedTriggeringPolicy interval="1" /> <SizeBasedTriggeringPolicy size="500 MB" /> <OnStartupTriggeringPolicy /> </Policies> <!-- 删除策略配置 --> <DefaultRolloverStrategy max="5000"> <Delete basePath="logs/app/history" maxDepth="1"> <!-- 配置且关系 --> <IfFileName glob="*.log.gz"/> <IfLastModified age="7d"/> </Delete> <!-- 配置或关系 --> <Delete basePath="logs/app/history" maxDepth="1"> <IfFileName glob="*.docx"/> </Delete> <Delete basePath="logs/app/history" maxDepth="1"> <IfFileName glob="*.vsdx"/> </Delete> </DefaultRolloverStrategy> </RollingFile>

　　另外说明，之所以能够无缝替换，是因为利用了不同实现版本的 org/slf4j/impl/StaticLoggerBinder.class, 而外部都使用 slf4j 接口定义实现的，比如 org.apache.logging.log4j:log4j-slf4j-impl 包的实现。

总结

到此这篇关于log4j2 自动删除过期日志文件的配置及实现原理解析的文章就介绍到这了,更多相关log4j2自动删除过期日志文件内容请搜索以前的文章或继续浏览下面的相关文章希望大家以后多多支持！