log4j2动态修改日志级别及拓展性使用

系统管理员 2021-10-18 14:56 636阅读 0赞

# 一、供参考的完整日志配置 #

<?xml version="1.0" encoding="UTF-8"?>
    
    
    <Configuration status="WARN">
    
        
        <Properties>
            <property name="basePath">${sys:vmparam}</property>
            <property name="filePath">${basePath}/app.log</property>
        </Properties>
    
        
        <Appenders>
            <Console name="Console" target="SYSTEM_OUT">
                <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
            </Console>
    
            
            <RollingFile name="RollingFile" fileName="${filePath}"
                filePattern="logs/$${date:yyyy-MM}/app-%d{yyyy-MM-dd-HH}-%i.log.gz">
                <Policies>
                    
                    <TimeBasedTriggeringPolicy interval="6" modulate="true"/>
                    <SizeBasedTriggeringPolicy size="250 MB"/>
                </Policies>
                
                <DefaultRolloverStrategy max="20"/>
    
                
                <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>
            
            <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="RollingFile" />
            </Root>
            
            
            <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>

# 二、动态修改日志级别 #

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);
    }

# 三、自定义appender #

以上介绍，均依赖于log4j2提供的官方配置，当对日志的业务逻辑复杂时，光靠配置也许满足不了需要，此时我们会想自己能操控打印的日志，做日志的路由，或保存等操作，这个时候就需要有自定义的appender，可以配置的就靠配置完成，不能的就自己写代码干预，而log4j2刚好提供了这样的拓展性。

如下代码即是自定义的Appender，通过实现AbstractAppender接口，配置@Plugin注解对应的信息并在eppend方法中写自己的业务逻辑，从而实现了对日志更大自由度的控制，如下展示的log4j配置文件中的配置节点名称要和注解中配置的name属性一致，并在Configuration节点配置好自定义Appender所在的包路径即可。  
　　Appender的自定义，可以参考log4j-core源码中org.apache.logging.log4j.core.appender.mom包中其它的扩展appender的实现。主要是实现AbstractAppender和AbstractManager。

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);
        }
    }

自定义appender配置