Java 日志 Log4j2

环境

jdk：1.7.0_79
cpu：i5-4570@3.20GHz 4核
eclipse：3.7
操作系统：win7

准备

1.log4j:1.7.21

  1. <dependency>
  2.         <groupId>org.slf4j</groupId>
  3.     <artifactId>slf4j-log4j12</artifactId>
  4.     <version>1.7.21</version>
  5. </dependency>

log4j.xml

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
  3. <log4j:configuration xmlns:log4j='http://jakarta.apache.org/log4j/'>
  5.     <appender name="myConsole" class="org.apache.log4j.ConsoleAppender">
  6.         <layout class="org.apache.log4j.PatternLayout">
  7.             <param name="ConversionPattern" value="[%d{dd HH:mm:ss,SSS\} %-5p] [%t] %c{2\} - %m%n" />
  8.         </layout>
  10.         <!--过滤器设置输出的级别 -->
  11.         <filter class="org.apache.log4j.varia.LevelRangeFilter">
  12.             <param name="levelMin" value="debug" />
  13.             <param name="levelMax" value="warn" />
  14.             <param name="AcceptOnMatch" value="true" />
  15.         </filter>
  16.     </appender>
  18.     <appender name="myFile" class="org.apache.log4j.DailyRollingFileAppender">
  19.         <param name="File" value="log4jTest.log" />
  20.         <param name="Append" value="true" />
  21.         <param name="DatePattern" value="'.'yyyy-MM-dd'.log'" />
  22.         <layout class="org.apache.log4j.PatternLayout">
  23.             <param name="ConversionPattern" value="[%t] - %m%n" />
  24.         </layout>
  25.     </appender>
  27.     <appender name="async_file" class="org.apache.log4j.AsyncAppender">
  28.         <param name="BufferSize" value="32" />
  29.         <appender-ref ref="myFile" />
  30.     </appender>
  32.     <logger name="org.logTest" additivity="false">
  33.         <level value="info" />
  34.         <appender-ref ref="async_file" /> <!-- 同步:FILE 异步:async_file -->
  35.     </logger>
  37. </log4j:configuration>

2.logback:1.1.7

  1. <dependency>
  2.     <groupId>ch.qos.logback</groupId>
  3.     <artifactId>logback-classic</artifactId>
  4.     <version>1.1.7</version>
  5. </dependency>

logback.xml

  1. <configuration>
  2.     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
  3.         <!-- encoder 默认配置为PatternLayoutEncoder -->
  4.         <encoder>
  5.             <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
  6.             </pattern>
  7.         </encoder>
  8.     </appender>
  10.     <appender name="FILE" class="ch.qos.logback.core.FileAppender">
  11.         <file>testFile.log</file>
  12.         <append>true</append>
  13.         <encoder>
  14.             <pattern>[%t] - %m%n
  15.             </pattern>
  16.         </encoder>
  17.     </appender>
  19.     <!-- 异步输出 -->
  20.     <appender name="ASYNC" class="ch.qos.logback.classic.AsyncAppender">
  21.         <discardingThreshold>0</discardingThreshold>
  22.         <appender-ref ref="FILE" />
  23.     </appender>
  25.     <logger name="org.logTest" level="INFO"
  26.         additivity="false">
  27.         <appender-ref ref="ASYNC" />  <!-- 同步:FILE 异步:ASYNC-->
  28.     </logger>
  30.     <root level="ERROR">
  31.         <appender-ref ref="STDOUT" />
  32.     </root>
  33. </configuration>

3.log4j2:2.6.2

  1. <dependency>
  2.     <groupId>org.apache.logging.log4j</groupId>
  3.     <artifactId>log4j-core</artifactId>
  4.     <version>2.6.2</version>
  5. </dependency>
  6. <dependency>
  7.     <groupId>org.apache.logging.log4j</groupId>
  8.     <artifactId>log4j-slf4j-impl</artifactId>
  9.     <version>2.6.2</version>
  10. </dependency>
  11. <dependency>
  12.     <groupId>com.lmax</groupId>
  13.     <artifactId>disruptor</artifactId>
  14.     <version>3.3.4</version>
  15. </dependency>

log4j2.xml

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <!--设置log4j2的自身log级别为warn -->
  3. <configuration status="warn">
  5.     <appenders>
  6.          <console name="Console" target="SYSTEM_OUT">
  7.             <PatternLayout pattern="[%d{HH:mm:ss:SSS}] [%p] - %l - %m%n" />
  8.         </console>
  10.         <RollingFile name="RollingFileInfo" fileName="info.log"
  11.             filePattern="${sys:user.home}/logs/hpaasvc/$${date:yyyy-MM}/info-%d{yyyy-MM-dd}-%i.log">
  12.             <Filters>
  13.                 <ThresholdFilter level="INFO" />
  14.                 <ThresholdFilter level="WARN" onMatch="DENY"
  15.                     onMismatch="NEUTRAL" />
  16.             </Filters>
  17.             <PatternLayout pattern="[%t] - %m%n" />
  18.             <Policies>
  19.                 <TimeBasedTriggeringPolicy />
  20.                 <SizeBasedTriggeringPolicy size="100 MB" />
  21.             </Policies>
  22.         </RollingFile>
  24.         <RandomAccessFile name="RandomAccessFile" fileName="asyncWithLocation.log"
  25.             immediateFlush="false" append="true">
  26.             <PatternLayout>
  27.                 <Pattern>[%t] - %m%n</Pattern>
  28.             </PatternLayout>
  29.         </RandomAccessFile>
  31.     </appenders>
  33.     <loggers>
  34.         <!-- <AsyncLogger name="asynLogger" level="trace"
  35.             includeLocation="true">
  36.             <AppenderRef ref="RandomAccessFile" />
  37.         </AsyncLogger> -->
  38.         <Root level="info" includeLocation="true">
  39.             <AppenderRef ref="RollingFileInfo" />
  40.         </Root>
  41.     </loggers>
  43. </configuration>

测试

准备50条线程同时记录1000000条数据，然后统计时间，详细代码如下：

  1. import java.util.concurrent.CountDownLatch;
  2. import org.slf4j.Logger;
  3. import org.slf4j.LoggerFactory;
  5. public class App {
  6.     private static Logger log = LoggerFactory.getLogger(App.class);
  8.     public static void main(String[] args) throws InterruptedException {
  9.         int messageSize = 1000000;
  10.         int threadSize = 50;
  11.         final int everySize = messageSize / threadSize;
  13.         final CountDownLatch cdl = new CountDownLatch(threadSize);
  14.         long startTime = System.currentTimeMillis();
  15.         for (int ts = 0; ts < threadSize; ts++) {
  16.             new Thread(new Runnable() {
  18.                 @Override
  19.                 public void run() {
  20.                     for (int es = 0; es < everySize; es++) {
  21.                         log.info("======info");
  22.                     }
  23.                     cdl.countDown();
  24.                 }
  25.             }).start();
  26.         }
  28.         cdl.await();
  29.         long endTime = System.currentTimeMillis();
  30.         System.out.println("log4j1:messageSize = " + messageSize
  31.                 + ",threadSize = " + threadSize + ",costTime = "
  32.                 + (endTime - startTime) + "ms");
  33.     }
  34. }

log4j1和logback的同步和异步分别修改为对应的appender就行了
log4j2的异步方式提供了2中模式：

1.全局开启

设置Log4jContextSelector系统属性为： 

  1. org.apache.logging.log4j.core.async.AsyncLoggerContextSelector
  2. System.setProperty("Log4jContextSelector", "org.apache.logging.log4j.core.async.AsyncLoggerContextSelector");

2.混合同步异步模式

不需要设置Log4jContextSelector，但是需要使用AsyncLogger标签
更多详细参考官方文档：http://logging.apache.org/log4j/2.x/manual/async.html#AllAsync
结果
分别测试完以后统计成表格如下：
2021-09-09-16-40-35-815318.png
log4j2的异步模式表现了绝对的性能优势，优势主要得益于Disruptor框架的使用

LMAX Disruptor technology. Asynchronous Loggers internally use the Disruptor, a lock-free inter-thread communication library, instead of queues, resulting in higher throughput and lower latency.

一个无锁的线程间通信库代替了原来的队列。