将log4j版本更新到1.1.5后未创建日志文件

Question

使用log4j library 1.1.4和slf4j-api 1.7.25在我的应用程序中进行日志记录可以很好地工作。

但是在将log4j库从1.1.4版本更新到1.1.5（或更高版本）之后，日志文件只会停止创建，不会产生任何异常或警告。即使是1.1.5版本也相当老，所以我宁愿使用更新的版本。配置的工作方式一定发生了变化，但我找不到是什么。

这段简单的代码将在Log4J1.1.4中创建滚动日志文件，但不会生成更新版本的日志文件。少了什么？

Maven依赖项包括：

    <dependencies>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jul-to-slf4j</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.1.4</version>
        </dependency>
    </dependencies>

代码：

package com.scratch.mylogtest;

import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.rolling.*;
import static java.nio.charset.StandardCharsets.UTF_8;

/**
 * A test of log file configuration and roll-over. It should simply create a log file then write enough data to it to cause the
 * file to roll-over to a new log file.
 */
public class LogbackTest1 {

  public static void main(String[] args) {
    final String LOG_LAYOUT = "%-5level \\(%logger{0}\\) [%date]: %m%n";

    final org.slf4j.Logger rootLogger = org.slf4j.LoggerFactory.getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
    rootLogger.info("Test of root logger prior to initialization");

    ((ch.qos.logback.classic.Logger) rootLogger).setLevel(ch.qos.logback.classic.Level.DEBUG);

    //set up the logging
    SLF4JBridgeHandler.removeHandlersForRootLogger(); //remove normal JUL logging...
    SLF4JBridgeHandler.install(); //...and route JUL logging to SLF4J

    LoggerContext loggerContext = ((ch.qos.logback.classic.Logger) rootLogger).getLoggerContext();

    //appender
    RollingFileAppender rollingFileAppender = new RollingFileAppender();
    rollingFileAppender.setContext(loggerContext);
    rollingFileAppender.setFile("C:\\ProgramData\\LogTest\\log-test.log");

    //encoder
    PatternLayoutEncoder patternLayoutEncoder = new PatternLayoutEncoder();
    patternLayoutEncoder.setContext(loggerContext);
    patternLayoutEncoder.setCharset(UTF_8);
    patternLayoutEncoder.setPattern(LOG_LAYOUT);
    patternLayoutEncoder.start();

    //rolling policy
    FixedWindowRollingPolicy fixedWindowRollingPolicy = new FixedWindowRollingPolicy();
    fixedWindowRollingPolicy.setContext(loggerContext);
    fixedWindowRollingPolicy.setParent(rollingFileAppender);
    fixedWindowRollingPolicy.setFileNamePattern("C:\\ProgramData\\LogTest\\log-test.log.%i");
    fixedWindowRollingPolicy.setMaxIndex(3);
    fixedWindowRollingPolicy.start();

    //triggering policy
    SizeBasedTriggeringPolicy triggeringPolicy = new SizeBasedTriggeringPolicy();
    triggeringPolicy.setMaxFileSize("100KB");

    //start appender
    rollingFileAppender.setEncoder(patternLayoutEncoder);
    rollingFileAppender.setRollingPolicy(fixedWindowRollingPolicy);
    rollingFileAppender.setTriggeringPolicy(triggeringPolicy);

    rollingFileAppender.start();

    //add appender
    ((ch.qos.logback.classic.Logger) rootLogger).addAppender(rollingFileAppender);

    final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(LogbackTest1.class);


    // Write some data into the logs.  Write enough data that it should cause the log file to roll-over to a new file
    logger.info("Starting");
    int logTestLines = 5000;
    for (int i = logTestLines; i > 0; i--) {
      logger.info("Log test line: " + i);
    }
    logger.info("Exiting");
  }

}

Answer 1

找到解决办法了！

在logback版本1.1.5中启动时，需要调用SizeBasedTriggeringPolicy.start()。在1.1.3版本中，这是不必要的。

从1.1.9版本开始，设置最大文件大小的方法也会发生变化，因此代码应该如下所示：

SizeBasedTriggeringPolicy<ILoggingEvent> triggeringPolicy = new SizeBasedTriggeringPolicy<>();
triggeringPolicy.setMaxFileSize(FileSize.valueOf("100KB"));
triggeringPolicy.start();

我用调试的方法发现了问题

StatusPrinter.print(loggerContext);

打印此信息的：

15:47:22,788 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[null] - TriggeringPolicy has not started. RollingFileAppender will not start

但如果不使用statusprinter，则不会打印任何警告。