大家好，我是烤鸭：

最近遇到一个问题，想把logback框架本身的日志级别修改，需要 logstash-logback-encoder 6.1 以上的版本才可以。

直接上代码

这里修改的不是业务日志级别，是 logback 框架本身(确切地说是 logstash-logback-encoder)这个包的日志级别，源码默认的是 WARN 级别，现在想改成只有ERROR的日志输出。

初始化加载类：

package com.xxx.reporter.flume;
​
import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.joran.JoranConfigurator;
import ch.qos.logback.core.joran.spi.JoranException;
import ch.qos.logback.core.status.OnConsoleStatusListener;
import ch.qos.logback.core.status.Status;
import ch.qos.logback.core.util.StatusPrinter;
import com.xxx.log.LogUtil;
import net.logstash.logback.status.LevelFilteringStatusListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
​
import java.net.URL;
​
/**
​* 自定义加载logback配置。*
​* @author 
​* @date 2020/7/23*/public class LogbackConfigLoader {
​private static final String LOGBACK_CONFIG = "logback.xml";
​/**
​* 重新加载logback 配置文件*/public static void load() {LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();try {// assume SLF4J is bound to logback in the current environmentURL url = LogbackConfigLoader.class.getClassLoader().getResource(LOGBACK_CONFIG);JoranConfigurator configurator = new JoranConfigurator();configurator.setContext(context);// Call context.reset() to clear any previous configuration, e.g. default// configuration. For multi-step configuration, omit calling context.reset().context.reset();// 初始化filter,并设置级别 ERRORaddDefaultFilter(context);configurator.doConfigure(url);} catch (JoranException je) {// StatusPrinter will handle thisLogUtil.log("LogbackConfigLoader error=" + je);}StatusPrinter.printIfErrorsOccured(context);
​}
​private static void addDefaultFilter(LoggerContext context) {context.getStatusManager().getCopyOfStatusListenerList();LevelFilteringStatusListener statusListener = new LevelFilteringStatusListener();statusListener.setLevelValue(Status.ERROR);statusListener.setDelegate(new OnConsoleStatusListener());statusListener.setContext(context);statusListener.start();context.getStatusManager().add(statusListener);}}

在项目启动的时候调一下这个方法就好了。

修改前以下的warn日志会打印，修改后就没了：

11:17:06,337 |-WARN in net.logstash.logback.appender.LogstashTcpSocketAppender[LOGSTASH] - Log destination xxx.com : 1234: Waiting 27476ms before attempting reconnection. 11:17:13,302 |-WARN in net.logstash.logback.appender.LogstashAccessTcpSocketAppender[logstash] - Log destination xxx.com : 1234: connection failed. java.net.ConnectException: Connection refused: connect at java.net.ConnectException: Connection refused: connect at at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) at at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:81) at at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:476) at at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:218) at at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:200) at at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:162) at at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:394) at at java.net.Socket.connect(Socket.java:606) at at net.logstash.logback.appender.AbstractLogstashTcpSocketAppender$TcpSendingEventHandler.openSocket(AbstractLogstashTcpSocketAppender.java:721) at at net.logstash.logback.appender.AbstractLogstashTcpSocketAppender$TcpSendingEventHandler.onStart(AbstractLogstashTcpSocketAppender.java:640) at at net.logstash.logback.appender.AsyncDisruptorAppender$EventClearingEventHandler.onStart(AsyncDisruptorAppender.java:351) at at com.xxx.arch.encoder.com.lmax.disruptor.BatchEventProcessor.notifyStart(BatchEventProcessor.java:224) at at com.xxx.arch.encoder.com.lmax.disruptor.BatchEventProcessor.run(BatchEventProcessor.java:120) at at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at at java.util.concurrent.FutureTask.run(FutureTask.java:266) at at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) at at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) at at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at at java.lang.Thread.run(Thread.java:748)

11:17:13,303 |-WARN in net.logstash.logback.appender.LogstashAccessTcpSocketAppender[logstash] - Log destination xxx.com : 1234: Waiting 27662ms before attempting reconnection.
 

根据自己的实际业务场景使用，有些 warn 还是有必要的 。建议能不改尽量不改。