如何在log4j中自动折叠重复日志输出

<filter class="com.example.DuplicateFilter" />

package com.example;

import org.apache.log4j.spi.Filter;
import org.apache.log4j.spi.LoggingEvent;

import java.util.HashMap;
import java.util.Map;

public class DuplicateFilter extends Filter {
    private Map<String, Integer> logCountMap = new HashMap<>();

    @Override
    public int decide(LoggingEvent event) {
        String logMessage = event.getRenderedMessage();
        if (logCountMap.containsKey(logMessage)) {
            int count = logCountMap.get(logMessage);
            count++;
            logCountMap.put(logMessage, count);
            return Filter.DENY;
        } else {
            logCountMap.put(logMessage, 1);
            return Filter.NEUTRAL;
        }
    }
}

<appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender">
    <layout class="org.apache.log4j.PatternLayout">
        <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n" />
    </layout>
    <filter class="com.example.DuplicateFilter" />
</appender>