java_spring boot 中使用 log4j2 及自定义layout设置示例

1. log4j2对比原始Logback 优势

对于 Spring Boot 3.x，Logback 是默认日志框架，但在高并发、异步日志场景下，Log4j2 通常表现更优。当业务百万级用户、微服务、日志量大时：

✅ 1. Logback（默认 Spring Boot 集成）

优势：

Spring Boot 原生支持：无需额外配置即可使用。
生态成熟：有 logstash-logback-encoder，方便输出 JSON 日志。
简单易用：配置相对直观，官方支持全面。
性能稳定：同步写日志表现很好。

劣势：

异步性能略弱于 Log4j2：需要借助 AsyncAppender，但整体吞吐比 Log4j2 略低。
无内建 LMAX Disruptor：在极端高并发下性能不如 Log4j2。

✅ 2. Log4j2

优势：

异步日志性能极强：基于 LMAX Disruptor，比 Logback AsyncAppender 快 10 倍以上。
支持异步安全：IO 密集型日志收集（比如发送到 Kafka）更高效。
灵活的 JSON Layout：自带 JsonTemplateLayout，不依赖第三方包。
热加载配置文件：支持修改日志级别而不重启服务。

劣势：

非默认框架：需要额外依赖，Spring Boot starter 需要 spring-boot-starter-log4j2 替换。
生态稍弱于 Logback：但主流场景完全足够。

2. 使用版本信息

spring boot 3.3.2
log4j2：跟随 spring boot版本，不必特意指定（spring boot 3.3.2 默认对应log4j2 版本是 2.24.0）
jackson： 2.17.2 （参考官网 https://github.com/apache/logging-log4j2/blob/rel/2.24.0/src/changelog/2.24.0/update_com_fasterxml_jackson_jackson_bom.xml）
win11下

父pom配置

    <!-- https://github.com/spring-projects/spring-boot/releases?page=4 --><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>3.3.2</version> <!--对应 mybatis-plus.version 3.5.8--><relativePath/></parent><properties><log4j2.version>2.24.0</log4j2.version> <!--spring boot 3.3.2 默认对应log4j2--><!--https://github.com/apache/logging-log4j2/blob/rel/2.24.0/src/changelog/2.24.0/update_com_fasterxml_jackson_jackson_bom.xml--><jackson.version>2.17.2</jackson.version><dependencyManagement><dependencies><!-- 核心 Spring Boot Starter，但排除默认日志框架 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><!-- 强制所有 commons-logging 排除 --><dependency><groupId>commons-logging</groupId><artifactId>commons-logging</artifactId><version>1.2</version> <!-- 任意真实存在的版本 --><!--标记 scope 为 provided，这样 Maven 会认为依赖存在，但不会打包--><scope>provided</scope></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-annotations</artifactId><version>${jackson.version}</version></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>${jackson.version}</version></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-core</artifactId><version>${jackson.version}</version></dependency></dependencies></dependencyManagement>

子使用模块 service-user 配置

pom配置：

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-log4j2</artifactId></dependency><!-- 可选：Log4j2 JSON Layout --><dependency><groupId>org.apache.logging.log4j</groupId><artifactId>log4j-layout-template-json</artifactId></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-annotations</artifactId></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-core</artifactId></dependency>

resources 中的 log4j2-spring.xml 配置

log4j2-spring.xml 必须放到 resources 目录下，不能再加一层目录。

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="TRACE" monitorInterval="30" messageFactory="org.apache.logging.log4j.message.ParameterizedMessageFactory"><Properties><Property name="LOG_PATH">C:/Data/logs</Property><Property name="LOG_FILE_NAME">log_${spring:spring.application.name:-unknown}</Property><Property name="service.name">${spring:spring.application.name:-unknown}</Property></Properties><Appenders><!-- 控制台输出（原始格式） --><Console name="Console" target="SYSTEM_OUT"><PatternLayout pattern="jjj %d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/></Console><!-- JSON 文件输出 --><RollingFile name="JsonFile" fileName="${LOG_PATH}/${LOG_FILE_NAME}.json"filePattern="${LOG_PATH}/${LOG_FILE_NAME}-%d{yyyy-MM-dd}-%i.json"><!-- <PatternLayout pattern="%d %p %C{1.} [%t] %m%n"/>--><JsonTemplateLayout eventTemplateUri="classpath:johnlogging/Log4j2JsonLayoutV4.json"/><Policies><TimeBasedTriggeringPolicy interval="1" modulate="true"/><SizeBasedTriggeringPolicy size="10MB"/></Policies><DefaultRolloverStrategy max="10"/></RollingFile></Appenders><Loggers><!--additivity 属性为“false”，表示在这个日志记录器中，日志不会被发送到它的父级日志记录器中--><Logger name="com.johnsport" level="info" additivity="false"><AppenderRef ref="Console" /><AppenderRef ref="JsonFile" /></Logger><Root level="INFO"><AppenderRef ref="Console"/><AppenderRef ref="JsonFile"/></Root></Loggers>
</Configuration>

Log4j2JsonLayout 自定义

resources 中的 johnlogging目录下 Log4j2JsonLayoutV4.json 配置如下，这个里面的内容不能随便写，需要参考官方文档中的定义，才能正确解析：JSON Template Layout :: Apache Log4j

{"timestamp": {"$resolver": "timestamp","pattern": {"format": "yyyy-MM-dd HH:mm:ss.SSS","timeZone": "Asia/Shanghai"}},"host": "${hostName:-unknown}","service": "${sys:service.name:-unknown}","level": {"$resolver": "level","field": "name"},"logger": {"$resolver": "logger","field": "name"},"source": {"$resolver": "source","field": "methodName"},"thread": {"$resolver": "thread","field": "name"},"message": {"$resolver": "message","stringified": true},"exception": {"$resolver": "exception","field": "stackTrace","stackTrace": {"stringified": {"truncation": {"suffix": "... [truncated]","pointMatcherStrings": ["servlet.http.HttpServlet"]}}}}
}

子使用模块service-user的 application.yml 相关定义：

spring:application:name: service-user# ...logging:config:- classpath:log4j2-spring.xmllevel:root: info

3. 输出样例

在指定的目录生成了log文件，名称为 log_service-user.json

示例内容（手动格式化了下）如下：

{"timestamp": "2025-08-17 19:29:43.094","host": "johnwang","service": "service-user","level": "INFO","logger": "com.yourcompanyname.projname.ServiceUserApplication","thread": "main","message": "Starting ServiceUserApplication v1.0-SNAPSHOT using Java 17.0.15 with PID 41056 (E:\\Data\\code_dir\\v0\\projname_back\\service\\service-user\\target\\service-user-1.0-SNAPSHOT.jar started by jopc in E:\\Data\\code_dir\\v0\\projname_back)"
}
{"timestamp": "2025-08-17 19:29:43.103","host": "johnwang","service": "service-user","level": "DEBUG","logger": "com.yourcompanyname.projname.ServiceUserApplication","thread": "main","message": "Running with Spring Boot v3.3.2, Spring v6.1.11"
}
{"timestamp": "2025-08-17 19:29:43.105","host": "johnwang","service": "service-user","level": "INFO","logger": "com.yourcompanyname.projname.ServiceUserApplication","thread": "main","message": "The following 1 profile is active: \"dev\""
}
{"timestamp": "2025-08-17 19:29:43.184","host": "johnwang","service": "service-user","level": "WARN","logger": "com.alibaba.cloud.nacos.configdata.NacosConfigDataLoader","thread": "main","message": "[Nacos Config] config[dataId=service-user.yaml, group=DEFAULT_GROUP] is empty"
}
{"timestamp": "2025-08-17 19:29:46.083","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.data.repository.config.RepositoryConfigurationDelegate","thread": "main","message": "Multiple Spring Data modules found, entering strict repository configuration mode"
}
{"timestamp": "2025-08-17 19:29:46.087","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.data.repository.config.RepositoryConfigurationDelegate","thread": "main","message": "Bootstrapping Spring Data Redis repositories in DEFAULT mode."
}
{"timestamp": "2025-08-17 19:29:46.128","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.data.repository.config.RepositoryConfigurationDelegate","thread": "main","message": "Finished Spring Data repository scanning in 19 ms. Found 0 Redis repository interfaces."
}
{"timestamp": "2025-08-17 19:29:46.538","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.cloud.context.scope.GenericScope","thread": "main","message": "BeanFactory id=5e73db5d-3847-3fef-bba4-62fff8906613"
}
{"timestamp": "2025-08-17 19:29:48.414","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.boot.web.embedded.tomcat.TomcatWebServer","thread": "main","message": "Tomcat initialized with port 7203 (http)"
}
{"timestamp": "2025-08-17 19:29:48.451","host": "johnwang","service": "service-user","level": "INFO","logger": "org.apache.coyote.http11.Http11NioProtocol","thread": "main","message": "Initializing ProtocolHandler [\"http-nio-7203\"]"
}
{"timestamp": "2025-08-17 19:29:48.457","host": "johnwang","service": "service-user","level": "INFO","logger": "org.apache.catalina.core.StandardService","thread": "main","message": "Starting service [Tomcat]"
}
{"timestamp": "2025-08-17 19:29:48.458","host": "johnwang","service": "service-user","level": "INFO","logger": "org.apache.catalina.core.StandardEngine","thread": "main","message": "Starting Servlet engine: [Apache Tomcat/10.1.26]"
}
{"timestamp": "2025-08-17 19:29:48.560","host": "johnwang","service": "service-user","level": "INFO","logger": "org.apache.catalina.core.ContainerBase.[Tomcat].[localhost].[/]","thread": "main","message": "Initializing Spring embedded WebApplicationContext"
}
{"timestamp": "2025-08-17 19:29:48.563","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext","thread": "main","message": "Root WebApplicationContext: initialization completed in 5369 ms"
}
{"timestamp": "2025-08-17 19:29:49.451","host": "johnwang","service": "service-user","level": "DEBUG","logger": "com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean","thread": "main","message": "Registered plugin: 'MybatisPlusInterceptor{interceptors=[PaginationInnerInterceptor(logger=org.apache.ibatis.logging.slf4j.Slf4jImpl@2adce412, overflow=false, maxLimit=null, dbType=MYSQL, dialect=null, optimizeJoin=true), com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor@629cf53c]}'"
}
{"timestamp": "2025-08-17 19:29:49.456","host": "johnwang","service": "service-user","level": "DEBUG","logger": "com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean","thread": "main","message": "Property 'mapperLocations' was not specified."
}
{"timestamp": "2025-08-17 19:29:51.897","host": "johnwang","service": "service-user","level": "INFO","logger": "com.alibaba.cloud.sentinel.SentinelWebMvcConfigurer","thread": "main","message": "[Sentinel Starter] register SentinelWebInterceptor with urlPatterns: [/**]."
}
{"timestamp": "2025-08-17 19:29:56.239","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.boot.actuate.endpoint.web.EndpointLinksResolver","thread": "main","message": "Exposing 1 endpoint beneath base path '/actuator'"
}
{"timestamp": "2025-08-17 19:29:56.414","host": "johnwang","service": "service-user","level": "INFO","logger": "org.apache.coyote.http11.Http11NioProtocol","thread": "main","message": "Starting ProtocolHandler [\"http-nio-7203\"]"
}
{"timestamp": "2025-08-17 19:29:56.439","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.boot.web.embedded.tomcat.TomcatWebServer","thread": "main","message": "Tomcat started on port 7203 (http) with context path '/'"
}
{"timestamp": "2025-08-17 19:29:56.771","host": "johnwang","service": "service-user","level": "INFO","logger": "com.alibaba.cloud.nacos.registry.NacosServiceRegistry","thread": "main","message": "nacos registry, DEFAULT_GROUP service-user 192.168.171.1:7203 register finished"
}
{"timestamp": "2025-08-17 19:29:57.606","host": "johnwang","service": "service-user","level": "INFO","logger": "com.yourcompanyname.projname.ServiceUserApplication","thread": "main","message": "Started ServiceUserApplication in 20.963 seconds (process running for 23.326)"
}
{"timestamp": "2025-08-17 19:29:57.724","host": "johnwang","service": "service-user","level": "INFO","logger": "com.alibaba.cloud.nacos.refresh.NacosContextRefresher","thread": "main","message": "[Nacos Config] Listening config: dataId=service-user.yaml, group=DEFAULT_GROUP"
}
{"timestamp": "2025-08-17 19:30:10.982","host": "johnwang","service": "service-user","level": "INFO","logger": "org.apache.catalina.core.ContainerBase.[Tomcat].[localhost].[/]","thread": "http-nio-7203-exec-1","message": "Initializing Spring DispatcherServlet 'dispatcherServlet'"
}
{"timestamp": "2025-08-17 19:30:10.982","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.web.servlet.DispatcherServlet","thread": "http-nio-7203-exec-1","message": "Initializing Servlet 'dispatcherServlet'"
}
{"timestamp": "2025-08-17 19:30:10.986","host": "johnwang","service": "service-user","level": "INFO","logger": "org.springframework.web.servlet.DispatcherServlet","thread": "http-nio-7203-exec-1","message": "Completed initialization in 3 ms"
}
{"timestamp": "2025-08-17 19:30:11.581","host": "johnwang","service": "service-user","level": "INFO","logger": "com.zaxxer.hikari.HikariDataSource","thread": "http-nio-7203-exec-1","message": "HikariCP - Starting..."
}
{"timestamp": "2025-08-17 19:30:12.007","host": "johnwang","service": "service-user","level": "INFO","logger": "com.zaxxer.hikari.pool.HikariPool","thread": "http-nio-7203-exec-1","message": "HikariCP - Added connection com.mysql.cj.jdbc.ConnectionImpl@d123cb8"
}
{"timestamp": "2025-08-17 19:30:12.014","host": "johnwang","service": "service-user","level": "INFO","logger": "com.zaxxer.hikari.HikariDataSource","thread": "http-nio-7203-exec-1","message": "HikariCP - Start completed."
}
{"timestamp": "2025-08-17 19:30:12.314","host": "johnwang","service": "service-user","level": "INFO","logger": "com.yourcompanyname.projname.guess.controller.GuessUserController","thread": "http-nio-7203-exec-1","message": "This is an info log test"
}
{"timestamp": "2025-08-17 19:30:12.314","host": "johnwang","service": "service-user","level": "WARN","logger": "com.yourcompanyname.projname.guess.controller.GuessUserController","thread": "http-nio-7203-exec-1","message": "This is a warn log test"
}
{"timestamp": "2025-08-17 19:30:41.521","host": "johnwang","service": "service-user","level": "INFO","logger": "com.yourcompanyname.projname.guess.controller.LogTestController","thread": "http-nio-7203-exec-2","message": "This is an info message"
}
{"timestamp": "2025-08-17 19:30:41.523","host": "johnwang","service": "service-user","level": "ERROR","logger": "com.yourcompanyname.projname.guess.controller.LogTestController","thread": "http-nio-7203-exec-2","message": "Division error occurred","exception": "java.lang.ArithmeticException: / by zero\r\n\tat com.yourcompanyname.projname.guess.controller.LogTestController.testLog(LogTestController.java:40)\r\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\r\n\tat java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)\r\n\tat java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\r\n\tat java.base/java.lang.reflect.Method.invoke(Method.java:568)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:255)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:188)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:926)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:831)\r\n\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:979)\r\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014)\r\n\tat org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903)\r\n\tat jakarta.servlet.http.HttpServlet\r\n... [truncated]"
}