Log4j2 在运行时添加记录器——这段代码有什么问题？

Question

在将项目从 log4j 迁移到 log4j2 时，我遇到了这样一种情况：必须在运行时添加将事件记录到单独文件（我们称之为 uu.log）的记录器 - 所有其他记录器都配置在属性文件。下面的代码几乎完成了这项工作——即 uu.log 包含来自所有现有记录器的事件，而不仅仅是来自新记录器的事件。到目前为止，这是我尝试过的：如何修复下面的代码以最简单的方式达到所需的状态？

public class MultipleLoggersExample {

    public static void main(String[] args) throws InterruptedException {

        // this logger is configured in properties file and is logging to own file
        Logger aud = LogManager.getLogger("aud");

        // class B is logging to separate file (logger also defined in properties)
        B b = new B();

        // below classes should log to common file NormalLog.log defined in properties
        C c = new C();
        D d = new D();
        E e = new E();

        addLoggerAtRuntime();

        // this logger needs to log only its OWN messages to uu.log file
        Logger runtimeLogger = LogManager.getLogger("my runtime logger");

        int counter = 2;
        while(true) {
            if(counter % 2 == 0){
                aud.info("message from \"aud\" logger no. "+ (counter-1));
            } else{
                b.logger.info("message from class B no. " + (counter-1));
            }
            c.logger.info("message from class C");
            e.logger.info("message from class E");

            if(counter % 4 == 0) {
                runtimeLogger.info("message from logger added at runtime");
            }
            counter++;
            Thread.sleep(5_000);
        }
    }

    private static void addLoggerAtRuntime() {
        final String fileName = "C:\Users\Damian\Desktop\uu.log";

        LoggerContext lc = (LoggerContext) LogManager.getContext(false);
        RollingFileAppender rfa = RollingFileAppender.newBuilder()
                .withName("my runtime logger").withAppend(true)
                .withFileName(fileName)
                .withLayout(PatternLayout.newBuilder().withPattern("%-5p %d [%t] %C{2} - %m%n").build())
                .withPolicy(TimeBasedTriggeringPolicy.newBuilder().withModulate(true).withInterval(2).build())
                .withFilePattern(fileName + "." + "%d{yyyy-MM-dd-HH-mm}")
                .setConfiguration(lc.getConfiguration()).build();
        rfa.start();
        lc.getConfiguration().addAppender(rfa);
        lc.getRootLogger().addAppender(lc.getConfiguration().getAppender(rfa.getName()));
        lc.updateLoggers();
    }

}

Answer 1

Appender 名称与记录器名称没有关系，因此：

.withName("my runtime logger")

毫无意义。你还不如用"My appender"什么的。

问题是这样的：

lc.getRootLogger().addAppender(

您正在将 Appender 添加到根记录器，所有其他记录器都继承自该根记录器，因此当然所有记录器都在使用它。尝试将 Appender 添加到您的记录器中：

lc.getLogger("my runtime logger").addAppender(

Log4j2 在运行时添加记录器——这段代码有什么问题？

Log4j2 add logger at runtime - what's wrong with this code?

java

logging

log4j2