4.log4j2实现日志脱敏

• 日志基础研究脑图

• 日志基础框架图

• 主要参考资料：

package com.zxy.demo.config;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.google.common.base.Objects;
import org.apache.commons.lang3.StringUtils;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.appender.rewrite.RewritePolicy;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.impl.Log4jLogEvent;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.message.ParameterizedMessage;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Set;

/**
 * DataMaskingRewritePolicy
 *
 * @author zhouxy
 * @date 2022/2/23
 **/
@Plugin(name = "DataMaskingRewritePolicy", category = "Core", elementType = "rewritePolicy", printObject = true)
public class DataMaskingRewritePolicy implements RewritePolicy {
    //使用静态内部类创建对象，节省空间
    private static class StaticDataMaskingRewritePolicy {
        private static final DataMaskingRewritePolicy dataMaskingRewritePolicy = new DataMaskingRewritePolicy();
    }

    //需要加密的字段配置数组
    private static final String[] encryptionKeyArrays = {"password"};
    //将数组转换为集合，方便查找
    private static final List<String> encryptionKeys = new ArrayList<>();

    public DataMaskingRewritePolicy() {
        if (CollectionUtils.isEmpty(encryptionKeys)) {
            encryptionKeys.addAll(Arrays.asList(encryptionKeyArrays));
        }
    }

    /**
     * 日志修改方法，可以对日志进行过滤，修改
     *
     * @param logEvent
     * @return
     */
    @Override
    public LogEvent rewrite(LogEvent logEvent) {
        if (!(logEvent instanceof Log4jLogEvent)) {
            return logEvent;
        }

        Log4jLogEvent log4jLogEvent = (Log4jLogEvent) logEvent;

        Message message = log4jLogEvent.getMessage();
        if (!(message instanceof ParameterizedMessage)) {
            return logEvent;
        }

        ParameterizedMessage parameterizedMessage = (ParameterizedMessage) message;

        Object[] params = parameterizedMessage.getParameters();
        if (params == null || params.length <= 0) {
            return logEvent;
        }
        Object[] newParams = new Object[params.length];
        for (int i = 0; i < params.length; i++) {
            try {
                JSONObject jsonObject = JSON.parseObject(params[i].toString());
                //处理json格式的日志
                newParams[i] = encryption(jsonObject, encryptionKeys);
            } catch (Exception e) {
                newParams[i] = params[i];
            }
        }

        ParameterizedMessage m = new ParameterizedMessage(parameterizedMessage.getFormat(), newParams, parameterizedMessage.getThrowable());
        Log4jLogEvent.Builder builder = log4jLogEvent.asBuilder().setMessage(m);
        return builder.build();
    }

    /**
     * 单例模式创建(静态内部类模式)
     *
     * @return
     */
    @PluginFactory
    public static DataMaskingRewritePolicy createPolicy() {
        return StaticDataMaskingRewritePolicy.dataMaskingRewritePolicy;
    }

    /**
     * 处理日志，递归获取值
     *
     * @Author zhouxy
     */
    private Object encryption(Object object, List<String> encryptionKeys) {
        String jsonString = JSON.toJSONString(object);
        if (object instanceof JSONObject) {
            JSONObject json = JSON.parseObject(jsonString);
            boolean isContain = encryptionKeys.stream().anyMatch(key -> StringUtils.contains(jsonString, key));
            if (isContain) {
                //判断当前字符串中有没有key值
                Set<String> keys = json.keySet();
                keys.forEach(key -> {
                    boolean result = encryptionKeys.stream().anyMatch(ekey -> Objects.equal(ekey, key));
                    if (result) {
                        String value = json.getString(key);
                        //加密
                        json.put(key, "****");
                    } else {
                        json.put(key, encryption(json.get(key), encryptionKeys));
                    }
                });
            }
            return json;
        } else if (object instanceof JSONArray) {
            JSONArray jsonArray = JSON.parseArray(jsonString);
            for (int i = 0; i < jsonArray.size(); i++) {
                JSONObject jsonObject = jsonArray.getJSONObject(i);
                //转换
                jsonArray.set(i, encryption(jsonObject, encryptionKeys));
            }
            return jsonArray;
        }
        return object;
    }
}

　　2.log4j2.xml配置，将重写类配置到log4j2.xml中，使用<Rewrite>标签。

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" monitorInterval="30">
    <Properties>
        <!-- 日志文件存放目录 -->
        ······
    </Properties>

    <Appenders>
        <!-- 控制台输出日志 -->
        <Console name="Console" target="SYSTEM_OUT" follow="true">
            ······
        </Console>
        <!-- 配置重写日志 -->
        <Rewrite name="rewrite">
            <DataMaskingRewritePolicy/>
            <AppenderRef ref="Console"/>
            <!-- 将catalina日志重写 -->
            <AppenderRef ref="Catalina"/>
        </Rewrite>

        <!-- Catalina日志 -->
        <RollingFile name="Catalina" fileName="${LOG_HOME}/catalina/catalina.log"
                     filePattern="${LOG_HOME}/catalina/catalina-%d{yyyy-MM-dd}-%i.log.gz">
           ······
        </RollingFile>
    </Appenders>

    <Loggers>
        ······

        <Root level="INFO">
            <AppenderRef ref="Catalina"/>
        <!-- 打印重写日志 -->
            <AppenderRef ref="rewrite"/>
        </Root>
    </Loggers>
</Configuration>

过程中遇到的问题：