Spring Boot使用log4j2管理日志

1 参考网站

# 开发文档
https://github.com/apache/logging-log4j2

# xml配置文档
https://logging.apache.org/log4j/2.x/manual/appenders.html

2 工程布局

3 log4j2配置

log4j2.xml文件，此文件不需要在application.yml文件中配置。

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" monitorInterval="60">
    <Properties>
        <!-- 设置应用的英文名称 -->
        <Property name="App">mylog</Property>
        <!-- 设置日志目录 -->
        <Property name="logDir">mylog/logs</Property>
        <Property name="splitSize">10 MB</Property>
        <property name="pattern">%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level  %msg \t %logger{36} %F %M %L %n </property>
    </Properties>

    <Appenders>
        <!-- 输出控制台日志的配置 -->
        <Console name="console" target="SYSTEM_OUT">
            <!-- 记录info和warn级别信息 -->
            <ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>
            <!-- 输出日志的格式 -->
            <PatternLayout pattern="${pattern}"/>
        </Console>

        <!-- 打印出所有的信息 -->
        <RollingFile name="info"
                     fileName="${logDir}/${App}-info.log"
                     filePattern="${logDir}/${App}-info-%d{yyyy-MM-dd}-%i.log.gz">
            <PatternLayout pattern="${pattern}"/>
            <Policies>
                <TimeBasedTriggeringPolicy interval="1" modulate="true"/>
                <SizeBasedTriggeringPolicy size="${splitSize}"/>
            </Policies>
            <Filters>
                <ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>
            </Filters>
            <DefaultRolloverStrategy max="20"/>
        </RollingFile>

        <!-- 存储所有error信息 -->
        <RollingFile name="error"
                     fileName="${logDir}/${App}-error.log"
                     filePattern="${logDir}/${App}-error-%d{yyyy-MM-dd}-%i.log.gz">
            <PatternLayout pattern="${pattern}" />
            <Policies>
                <TimeBasedTriggeringPolicy interval="1" modulate="true"/>
                <SizeBasedTriggeringPolicy size="${splitSize}"/>
            </Policies>
            <Filters>
                <ThresholdFilter level="error" onMatch="ACCEPT" onMismatch="DENY"/>
            </Filters>
            <DefaultRolloverStrategy max="20"/>
        </RollingFile>
    </Appenders>

    <Loggers>
        <Root level="info">
            <AppenderRef ref="console"/>
            <AppenderRef ref="info"/>
            <AppenderRef ref="error"/>
        </Root>
    </Loggers>
</Configuration>

4 pom.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.2.5.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>mylog</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>mylog</name>
	<description>Mylog project for Spring Boot</description>
	<properties>
		<java.version>11</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<!-- Init the entity -->
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<version>1.18.20</version>
			<scope>provided</scope>
		</dependency>

		<!-- Import the log4j2 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-log4j2</artifactId>
		</dependency>

		<!-- Remove the internal dependency log spring-boot-starter-logging  -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-logging</artifactId>
			<exclusions>
				<exclusion>
					<groupId>*</groupId>
					<artifactId>*</artifactId>
				</exclusion>
			</exclusions>
		</dependency>


		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>

	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<version>2.3.1.RELEASE</version>
			</plugin>
		</plugins>
	</build>

</project>

5 SpringBoot使用Log4j2

5.1 使用LoggerFactory采集日志

TestLogController.java。

package com.example.mylog.controller;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@RequestMapping("/log")
@ResponseBody
public class TestLogController {

    @GetMapping("/test")
    public String test(){

        Logger logger = LoggerFactory.getLogger(TestLogController.class);

        logger.trace("trace level");
        logger.debug("debug level");
        logger.info("info level");
        logger.warn("warn level");
        logger.error("error level");

        return "1";
    }

}

5.2 使用lombok采集日志

TestLogLombokController.java

package com.example.mylog.controller;

import lombok.extern.log4j.Log4j2;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@RequestMapping("/lomlog")
@ResponseBody
@Log4j2
public class TestLogLombokController {

    @GetMapping("/test")
    public String test(){

        log.trace("Lombok trace level");
        log.debug("Lombok debug level");
        log.info("Lombok info level");
        log.warn("Lombok warn level");
        log.error("Lombok error level");

        return "1";
    }
}