最通俗易懂的 JAVA slf4j,log4j,log4j2,logback 关系与区别以及完整集成案例

 <!--slf4j 依赖-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.25</version>
        </dependency>
        <!-- logback依赖 -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <!--通用格式配置-->
    <property name="pattern" value="[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} %c %M %L %thread %m%n"/>
    <!-- 配置文件的输出路径 -->
    <property name="logDir" value="E:/code/log"/>

    <!-- 配置文件的appender 普通文件-->
    <appender name="fileAppender" class="ch.qos.logback.core.FileAppender">
        <!-- 引入文件位置 -->
        <file>${logDir}/test_logback.log</file>
        <!-- 配置日志输出格式 -->
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <!-- 格式引用通用属性配置 -->
            <pattern>${pattern}</pattern>
        </encoder>
    </appender>

    <!-- 配置控制台appender -->
    <appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender">
        <!--默认：System.out 表示以黑色字体输出日志-->
        <!--设置：System.err 表示以红色字体输出日志-->
        <target>
            System.err
        </target>
        <!--配置日志输出格式-->
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <!-- 格式引用通用属性配置 -->
            <pattern>${pattern}</pattern>
        </encoder>
    </appender>
    <!--
        日志记录器
        配置root logger
        level：配置日志级别
        可以同时配置多个appender，做日志的多方向输出
    -->
    <root level="ALL">
        <!-- 引入控制台appender -->
        <appender-ref ref="consoleAppender"/>
        <!-- 引入普通文件appender -->
        <appender-ref ref="fileAppender"/>
    </root>
</configuration>

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @Author alan.wang
 */
public class LogTester {

    private static Logger logger = LoggerFactory.getLogger(LogTester.class);

    public static void main(String[] args){
        logger.debug("这是Log4j2 debug");
        logger.info("这是Log4j2 info");
        logger.warn("这是Log4j2 warn");
        logger.error("这是Log4j2 error");
    }

}

 <!--log4j2 依赖-->
        <!-- Slf4j的核心包，只有日志的接口，整合log4j2并没有实现 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.25</version>
        </dependency>
        <!-- 桥接器，将JCL的日志输出重定向到Slf4j中 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
            <version>1.7.25</version>
            <scope>runtime</scope>
        </dependency>
        <!-- 导入日志框架核心包与接口包 -->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.9.1</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.9.1</version>
            <scope>runtime</scope>
        </dependency>
        <!--用于slf4j与log4j2保持桥接 -->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-slf4j-impl</artifactId>
            <version>2.9.1</version>
            <scope>runtime</scope>
        </dependency>
        <!--用于解决web环境下关闭服务器时可能出现的log4j线程无法及时关闭的warn，web工程需要包含log4j-web，非web工程不需要 -->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-web</artifactId>
            <version>2.9.1</version>
            <scope>runtime</scope>
        </dependency>
        <!--使用log4j2的AsyncLogger时需要包含disruptor -->
        <dependency>
            <groupId>com.lmax</groupId>
            <artifactId>disruptor</artifactId>
            <scope>runtime</scope>
            <version>3.4.2</version>
        </dependency>

<Configuration status="warn" monitorInterval="30">

    <Properties>
        <!-- 需要配置日志目录 -->
        <Property name="baseDir">E:/code/log</Property>
        <Property name="appName">test_log4j2</Property>
        <Property name="pattern">%d %-5p [%t] [%c{1.}] %.-300m%n</Property>
    </Properties>

    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="${pattern}"/>
        </Console>

        <RollingFile name="File" fileName="${baseDir}/${appName}/${appName}.log" filePattern="${baseDir}/${appName}/%d{yyyyMMdd}-%i.${appName}.log">
            <PatternLayout pattern="${pattern}"/>

            <Policies>
                <TimeBasedTriggeringPolicy/>
                <SizeBasedTriggeringPolicy size="2048 MB"/>
            </Policies>

            <DefaultRolloverStrategy max="30">
                <Delete basePath="${baseDir}/${appName}" maxDepth="1">
                    <IfFileName glob="*/*.log"/>
                    <IfLastModified age="20d"/>
                </Delete>
            </DefaultRolloverStrategy>
        </RollingFile>

    </Appenders>

    <Loggers>

        <Root level="debug" includeLocation="false" additivity="false">
            <AppenderRef ref="Console"/>
            <AppenderRef ref="File"/>
        </Root>
    </Loggers>
</Configuration>

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @Author alan.wang
 */
public class LogTester {

    private static Logger logger = LoggerFactory.getLogger(LogTester.class);

    public static void main(String[] args){
        logger.debug("这是Log4j2 debug");
        logger.info("这是Log4j2 info");
        logger.warn("这是Log4j2 warn");
        logger.error("这是Log4j2 error");
    }

}