Spring Boot 3.5.3 集成 Log4j2 日志系统

发布于：2025-09-03 ⋅ 阅读:(15) ⋅ 点赞:(0)

在 Spring Boot 3.5.3 中，要将默认的 Logback 替换为 Log4j2，需要以下步骤：

1. 添加 Log4j2 依赖

在 pom.xml中排除默认的 Logback 依赖并添加 Log4j2 依赖：

<dependencies>
    <!-- 排除默认的 Logback -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-logging</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    
    <!-- 添加 Log4j2 Starter -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-log4j2</artifactId>
    </dependency>
    
    <!-- 可选：日志配置刷新支持 -->
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-liquibase</artifactId>
    </dependency>
</dependencies>

2. 创建 Log4j2 配置文件

在 src/main/resources目录下创建 log4j2.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" monitorInterval="30">
    <Appenders>
        <!-- 控制台输出 -->
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
        </Console>
        
        <!-- 文件输出 -->
        <RollingFile name="File" fileName="logs/application.log"
                     filePattern="logs/application-%d{yyyy-MM-dd}-%i.log">
            <PatternLayout>
                <Pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n</Pattern>
            </PatternLayout>
            <Policies>
                <!-- 每天滚动 -->
                <TimeBasedTriggeringPolicy />
                <!-- 文件大小达到100MB时滚动 -->
                <SizeBasedTriggeringPolicy size="100 MB"/>
            </Policies>
            <!-- 保留最近7天的日志 -->
            <DefaultRolloverStrategy max="7"/>
        </RollingFile>
        
        <!-- 异步日志配置 -->
        <Async name="Async" bufferSize="262144">
            <AppenderRef ref="File"/>
        </Async>
    </Appenders>
    
    <Loggers>
        <!-- Spring Boot 核心日志 -->
        <Logger name="org.springframework" level="INFO"/>
        <Logger name="org.apache" level="WARN"/>
        
        <!-- Hibernate 日志 -->
        <Logger name="org.hibernate.SQL" level="DEBUG" additivity="false">
            <AppenderRef ref="Console"/>
        </Logger>
        <Logger name="org.hibernate.type.descriptor.sql" level="TRACE" additivity="false">
            <AppenderRef ref="Console"/>
        </Logger>
        
        <!-- 自定义包日志级别 -->
        <Logger name="com.myapp" level="DEBUG"/>
        
        <!-- Root 日志设置 -->
        <Root level="INFO">
            <AppenderRef ref="Console"/>
            <AppenderRef ref="Async"/> <!-- 使用异步文件输出 -->
        </Root>
    </Loggers>
</Configuration>

3. 添加 application.yml 配置

在 application.yml中添加 Log4j2 相关配置：

spring:
  application:
    name: my-application
  
logging:
  config: classpath:log4j2.xml
  level:
    root: info
    org.springframework.web: debug
    com.myapp.service: trace
  
  # 启用日志配置热更新
  log4j2:
    watch: true
    shutdown-hook: disable
    shutdown-timeout: 30

4. 添加日志工具类

创建日志工具类以简化使用：

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class LogUtil {
    private LogUtil() {}
    
    public static Logger getLogger() {
        // 获取调用此方法的上层类名
        return LogManager.getLogger(Thread.currentThread().getStackTrace()[2].getClassName());
    }
    
    // 方法入参日志（使用MDC添加上下文信息）
    public static void logMethodEntry(Object... params) {
        Logger logger = getLogger();
        if(logger.isTraceEnabled()) {
            String methodName = Thread.currentThread().getStackTrace()[2].getMethodName();
            logger.trace("Entering: {} with params: {}", methodName, params);
        }
    }
}

5. 高级功能配置

5.1 日志脱敏配置

添加敏感信息脱敏配置类：

import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.pattern.ConverterKeys;
import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;

@Plugin(name = "SafeConverter", category = "Converter")
@ConverterKeys({"safe"})
public class SafeConverter extends LogEventPatternConverter {
    // 敏感信息正则匹配
    private static final String SENSITIVE_PATTERN = 
        "\\b(?:password|passwd|pwd|secret|token|key|card|ccn|phone|tel|id)\\b[^=]*=\\s*['\"]?([^'\",\\s]+)";
    
    protected SafeConverter() {
        super("safe", "safe");
    }
    
    public static SafeConverter newInstance(String[] options) {
        return new SafeConverter();
    }
    
    @Override
    public void format(LogEvent event, StringBuilder toAppendTo) {
        String message = event.getMessage().getFormattedMessage();
        toAppendTo.append(message.replaceAll(SENSITIVE_PATTERN, "$1=***"));
    }
}

在 log4j2.xml中使用：

<PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{36} - %safe{%msg}%n"/>

5.2 日志指标监控

添加 Log4j2 指标采集：

import io.micrometer.core.instrument.MeterRegistry;
import org.apache.logging.log4j.LogManager;
import org.springframework.context.annotation.Configuration;

import javax.annotation.PostConstruct;

@Configuration
public class LogMetricsConfig {
    private final MeterRegistry meterRegistry;
    
    public LogMetricsConfig(MeterRegistry meterRegistry) {
        this.meterRegistry = meterRegistry;
    }
    
    @PostConstruct
    public void init() {
        // 采集ERROR级别的日志计数
        meterRegistry.gauge("log.error.count", 
            LogManager.getRootLogger(), 
            logger -> logger instanceof org.apache.logging.log4j.core.Logger 
                ? ((org.apache.logging.log4j.core.Logger) logger).getCount().get() 
                : 0
        );
    }
}

5.3 日志集中式管理

添加 Logstash 或 ELK 支持：

<!-- pom.xml 添加依赖 -->
<dependency>
    <groupId>net.logstash.logback</groupId>
    <artifactId>logstash-logback-encoder</artifactId>
    <version>7.3</version>
</dependency>

配置 Logstash Appender：

<Appenders>
    <!-- Logstash TCP 输出 -->
    <LogstashTcpSocket name="Logstash" host="logstash.mycompany.com" port="5000">
        <JsonLayout compact="true" eventEol="true">
            <KeyValuePair key="appName" value="${spring:spring.application.name}"/>
            <KeyValuePair key="environment" value="${spring:spring.profiles.active}"/>
        </JsonLayout>
    </LogstashTcpSocket>
</Appenders>

<Loggers>
    <Root level="INFO">
        <AppenderRef ref="Logstash"/>
    </Root>
</Loggers>

6. Spring Boot 配置类

添加日志相关的配置管理：

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.core.LoggerContext;
import org.springframework.boot.context.event.ApplicationStartedEvent;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.event.EventListener;

import java.net.URI;

@Configuration
public class LogConfig {
    
    /**
     * 应用启动后重新加载日志配置
     */
    @EventListener(ApplicationStartedEvent.class)
    public void reloadLogConfig() {
        LoggerContext context = (LoggerContext) LogManager.getContext(false);
        context.setConfigLocation(URI.create("classpath:log4j2.xml"));
        context.reconfigure();
    }
}

7. 日志性能优化

7.1 异步日志配置优化

<!-- log4j2.xml -->
<AsyncLogger name="com.myapp" level="debug" additivity="false">
    <AppenderRef ref="Console"/>
    <AppenderRef ref="File"/>
    <!-- 队列大小 -->
    <AsyncQueueSize>262144</AsyncQueueSize>
    <!-- 等待策略 -->
    <AsyncWaitStrategy type="Block"/>
</AsyncLogger>

7.2 日志开关控制器

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.config.Configurator;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class LogController {
    
    @GetMapping("/log/level")
    public String changeLogLevel(String logger, String level) {
        LoggerContext context = (LoggerContext) LogManager.getContext(false);
        
        // 设置特定日志级别
        if ("root".equalsIgnoreCase(logger)) {
            Configurator.setRootLevel(Level.valueOf(level));
        } else {
            Configurator.setLevel(logger, Level.valueOf(level));
        }
        
        context.reconfigure();
        return "Log level updated: " + logger + " -> " + level;
    }
}

8. 验证日志配置

创建测试控制器验证日志输出：

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class LogTestController {
    private static final Logger logger = LogManager.getLogger(LogTestController.class);
    
    @GetMapping("/test/log")
    public String testLog() {
        logger.trace("This is a TRACE message");
        logger.debug("This is a DEBUG message");
        logger.info("This is an INFO message");
        logger.warn("This is a WARN message");
        logger.error("This is an ERROR message");
        
        return "Log messages generated!";
    }
}

访问 http://localhost:8080/test/log后，检查控制台和日志文件验证输出。

配置总结

功能

配置位置

说明

基础配置

log4j2.xml

定义日志格式、输出目的地等

级别控制

application.yml

设置不同包的日志级别

热更新

logging.log4j2.watch

配置自动检测配置变化

异步日志

Async Appender

提高日志性能

日志脱敏

SafeConverter

保护敏感信息

日志监控

Micrometer

采集日志指标

远程日志

LogstashTcpSocket

集成ELK栈

此配置提供了：

  1. 灵活的日志级别控制

  2. 高性能的异步日志处理

  3. 敏感信息保护

  4. 监控和管理功能

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