log4j2动态修改日志级别及拓展性使用详解

<?xml version="1.0" encoding="UTF-8"?>

<!-- 配置LoggerConfig，即Appenders的日志级别为WARN -->
<Configuration status="WARN">

  <!-- 定义下面的引用名 -->
  <Properties>
    <property name="basePath">${sys:vmparam}</property>
    <property name="filePath">${basePath}/app.log</property>
  </Properties>

  <!-- Appenders支持配置多个Appender，支持向不同的目标输送日志，本例为配置向控制台输出 -->
  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
    </Console>

    <!-- 将日志输出到指定位置的文件中 -->
    <RollingFile name="RollingFile" fileName="${filePath}"
      filePattern="logs/$${date:yyyy-MM}/app-%d{yyyy-MM-dd-HH}-%i.log.gz">
      <Policies>
        <!-- interval单位为filePattern最后一个单位，此处为6小时，modulate若为true，
        则日志时间将以0点为边界进行偏移计算，由于加了.gz策略，所以此处意思为每隔6小时，便会新生成一个
        log4j2的压缩文件，当每个文件超过250M时，也会新生成一个log4j2的压缩文件 -->
        <TimeBasedTriggeringPolicy interval="6" modulate="true"/>
        <SizeBasedTriggeringPolicy size="250 MB"/>
      </Policies>
      <!-- 滚动策略，日志文件最多保留20个 -->
      <DefaultRolloverStrategy max="20"/>

      <!-- 最多备份30天以内||日志文件大小达到100GB的日志||文件数量超过十个
      此处为策略限制，Delete中可以按自己需要用正则表达式编写 -->
      <DefaultRolloverStrategy>
        <Delete basePath="${filePath}" maxDepth="1">
          <IfFileName glob="logs_*.log" />
          <IfLastModified age="30d" />
          <IfAccumulatedFileSize exceeds="100 GB" />
          <IfAccumulatedFileCount exceeds="10" />
        </Delete>
      </DefaultRolloverStrategy>
    </RollingFile>
  </Appenders>

  <!-- Loggers支持配置多个Logger，可引用不同的目标Appender，也可根据业务需求定制特定要求的Appender -->
  <Loggers>
    
    <AsyncLogger name="AsyncLogger" level="trace">
      <appender-ref ref="Console" />
      <appender-ref ref="RollingFile" />
    </AsyncLogger>
 
    <asyncRoot level="trace">
      <appender-ref ref="Console" />
    </asyncRoot> 
    
    <Root level="info">
      <!-- <AppenderRef ref="Console" /> -->
      <AppenderRef ref="RollingFile" />
    </Root>
    
    <!-- 第三方日志系统 -->
    <logger name="org.springframework" level="INFO" additivity="false">
      <appender-ref ref="Console" />
    </logger>
    <logger name="io.netty" level="warn"/>
    <logger name="org.apache.http" level="warn"/>
    <logger name="org.mongodb.driver" level="INFO"/>
    <logger name="org.jboss.netty" level="warn"/>
    <logger name="org.springframework.data.redis" level="INFO"/>
  </Loggers>
</Configuration>

Collection<org.apache.logging.log4j.core.Logger> current = LoggerContext.getContext(false).getLoggers();
Collection<org.apache.logging.log4j.core.Logger> notcurrent = LoggerContext.getContext().getLoggers();
Collection<org.apache.logging.log4j.core.Logger> allConfig = current;
allConfig.addAll(notcurrent);
for (org.apache.logging.log4j.core.Logger log:allConfig){
  log.setLevel(Level.DEBUG);
}　

package com.jyk.log4j2.log4j2_test;

import java.io.Serializable;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.appender.AbstractAppender;
import org.apache.logging.log4j.core.appender.AppenderLoggingException;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.layout.PatternLayout;
 
@Plugin(name = "MyAppender", category = "Core", elementType = "appender", printObject = true)
public class MyAppender extends AbstractAppender {
 
  /**
   * @fields serialVersionUID
   */
  private static final long serialVersionUID = -830237775522429777L;
  private final ReadWriteLock rwLock = new ReentrantReadWriteLock();
  private final Lock readLock = rwLock.readLock();
 
  //需要实现的构造方法，直接使用父类就行
  protected MyAppender(final String name, final Filter filter, final Layout<? extends Serializable> layout,
      final boolean ignoreExceptions) {
    super(name, filter, layout, ignoreExceptions);
  }
 
  @Override
  public void append(LogEvent event) {
    readLock.lock();
    try {
      final byte[] bytes = getLayout().toByteArray(event);//日志二进制文件，输出到指定位置就行
      
      //拿到每次打印的日志，写自己的业务逻辑
      System.out.println("enter my append...");
    } catch (Exception ex) {
      if (!ignoreExceptions()) {
        throw new AppenderLoggingException(ex);
      }
    } finally {
      readLock.unlock();
    }
  }
 
  // 下面这个方法可以接收配置文件中的参数信息
  @PluginFactory
  public static MyAppender createAppender(@PluginAttribute("name") String name,
      @PluginElement("Filter") final Filter filter,
      @PluginElement("Layout") Layout<? extends Serializable> layout,
      @PluginAttribute("ignoreExceptions") boolean ignoreExceptions) {
    if (name == null) {
      LOGGER.error("No name provided for MyCustomAppenderImpl");
      return null;
    }
    if (layout == null) {
      layout = PatternLayout.createDefaultLayout();
    }
    return new MyAppender(name, filter, layout, ignoreExceptions);
  }
}

<Configuration status="WARN" packages="com.jyk.log4j2.log4j2_test">

<MyAppender name="textarea">
      <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
</MyAppender>