Log4j2调用setThreshold关闭指定Appender报错如何解决

• 你混用了Log4j 1.x和Log4j 2.x的API：setThreshold()是Log4j 1.x的AppenderSkeleton类的方法，Log4j 2.x的org.apache.logging.log4j.core.Appender接口没有这个方法
• 代码中还错误引入了org.apache.log4j.Level，Log4j 2.x的级别类是org.apache.logging.log4j.Level

如果你只是需要完全关闭指定Appender的输出，直接从RootLogger上移除对应Appender的引用即可，需要恢复时再加回来就行：

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.LoggerConfig;

private static Logger logger = LoggerFactory.getLogger(UserOptions.class);

public void adjustAppenderStatus() {
    // 类加载器隔离场景（如Spring Boot、Web容器）建议传false获取当前应用的上下文
    LoggerContext loggerContext = (LoggerContext) LogManager.getContext(false);
    Configuration configuration = loggerContext.getConfiguration();
    LoggerConfig rootLoggerConfig = configuration.getRootLogger();

    // 控制控制台输出
    if (!getOptionsAdditionalLoggingIsToConsole()) {
        rootLoggerConfig.removeAppender("Console");
    } else {
        // 需要恢复时添加引用，Level传null表示继承RootLogger的级别
        rootLoggerConfig.addAppender(configuration.getAppender("Console"), null, null);
    }

    // 控制文件输出
    if (!getOptionsAdditionalLoggingIsToFile()) {
        rootLoggerConfig.removeAppender("File");
    } else {
        rootLoggerConfig.addAppender(configuration.getAppender("File"), null, null);
    }

    // 必须调用该方法让修改后的配置生效
    loggerContext.updateLoggers(configuration);
}

如果后续需要灵活调整Appender的输出级别，而不是仅完全关闭，可以给Appender添加ThresholdFilter动态修改阈值：

import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.appender.AbstractAppender;
import org.apache.logging.log4j.core.filter.ThresholdFilter;
import org.apache.logging.log4j.Level;

// 调整Console Appender阈值为OFF，完全关闭输出
if (!getOptionsAdditionalLoggingIsToConsole()) {
    AbstractAppender consoleAppender = (AbstractAppender) configuration.getAppender("Console");
    // 新建阈值过滤器，匹配级别等于及高于OFF的日志全部拒绝
    ThresholdFilter offFilter = ThresholdFilter.createFilter(Level.OFF, Filter.Result.DENY, Filter.Result.ACCEPT);
    consoleAppender.addFilter(offFilter);
}

// 修改后要更新配置生效
loggerContext.updateLoggers(configuration);

• 项目中建议排除Log4j 1.x的传递依赖，避免两类API混用冲突
• 所有配置修改完成后必须调用loggerContext.updateLoggers(configuration)才能生效

内容的提问来源于stack exchange，提问作者Alexei