java日志管理 - slf4j+log4j2

1 . 概述

1.1  日志框架实现

• log4j是apache实现的一个开源日志组件；
• logback同样是由log4j的作者设计完成的，拥有更好的特性，用来取代log4j的一个日志框架，是slf4j的原生实现；
• log4j2是log4j 1.x和logback的改进版，据说采用了一些新技术（无锁异步、等等），使得日志的吞吐量、性能比log4j 1.x提高10倍，并解决了一些死锁的bug，而且配置更加简单灵活，官网地址： http://logging.apache.org/log4j/2.x/manual/configuration.html

1.2  日志接口

　　slf4j是对所有日志框架制定的一种规范、标准、接口，并不是一个框架的具体的实现，需要和具体的日志框架实现配合使用（如log4j、logback）。

　　使用日志接口便于更换为其他日志框架。

　　

2. 使用log4j2

使用maven配置log4j2，pom.xml中引入log4j-api 和 log4j-core即可。

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>tdtech.practice</groupId>
    <artifactId>achitechture</artifactId>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <log4j.version>2.8.2</log4j.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>${log4j.version}</version>
        </dependency>

    </dependencies>
</project>

java代码示例：

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

public class LogUtil {
　　 //引入的是log4j自身的包
    static Logger log = LogManager.getLogger();

    public static void main(String[] args) {
        String param1 = "string1";
        String param2 = "string2";

        log.error("--占位符的方式拼接效率更高-- {} -- {}", param1, param2);
    }
}

output：
00:10:12.063 [main] ERROR eagle.log.LogUtil - --占位符的方式拼接效率更高-- string1 -- string2

 3. 使用slf4j+log4j2接口

pom.xml中除了引入上述log4j2的包，还需引入slf4j的包：

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>tdtech.practice</groupId>
    <artifactId>achitechture</artifactId>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <slf4j.version>1.7.25</slf4j.version>
        <log4j.version>2.8.2</log4j.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>${log4j.version}</version>
        </dependency>

        <!-- slf4j核心包-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
            <version>${slf4j.version}</version>
            <scope>runtime</scope>
        </dependency>

        <!--slf4j绑定log4j实现-->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-slf4j-impl</artifactId>
            <version>${log4j.version}</version>
        </dependency>

    </dependencies>
</project>

java代码示例：

package eagle.log;

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

public class LogUtil {
    //引入的是slf4j接口的包
    static Logger log = LoggerFactory.getLogger(LogUtil.class);

    public static void main(String[] args) {
        String param1 = "string1";
        String param2 = "string2";

        log.error("--占位符的方式拼接效率更高-- {} -- {}", param1, param2);
    }
}

4. log4j2的配置

classpath下添加log4j2.xml，示例：

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO" monitorInterval="300">
    <Appenders>
        <Console name="console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%t] [%file:%line] - %msg%n"/>
        </Console>

        <RollingRandomAccessFile name="gatekeeperFile"
                                 fileName="${bundle:gatekeeper:LOG_HOME}/gatekeeper.log"
                                 filePattern="${bundle:gatekeeper:LOG_HOME}/$${date:yyyy-MM-dd}/gatekeeper-%d{yyyy-MM-dd HH-mm}-%i.log.xz"
                                 immediateFlush="false">
            <PatternLayout
                    pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%t] [%file:%line] - %msg%n"/>
            <Policies>
                <TimeBasedTriggeringPolicy interval="60"/>
                <SizeBasedTriggeringPolicy size="20 MB"/>
            </Policies>
            <DefaultRolloverStrategy max="10">
                <!--
                Nested conditions: the inner condition is only evaluated on files
                for which the outer conditions are true.
                -->
                <Delete basePath="${bundle:gatekeeper:LOG_HOME}" maxDepth="2">
                    <IfFileName glob="*/gatekeeper-*.log.xz">
                        <IfLastModified age="30d">
                        </IfLastModified>
                    </IfFileName>
                </Delete>
            </DefaultRolloverStrategy>
        </RollingRandomAccessFile>
    </Appenders>

    <Loggers>
        <AsyncLogger name="org.springframework" level="info" additivity="false" includeLocation="true">
            <AppenderRef ref="springFile"/>
        </AsyncLogger>
        <AsyncLogger name="com.tdtech.eplatform.gatekeeper" level="info" additivity="false" includeLocation="true">
            <AppenderRef ref="gatekeeperFile"/>
        </AsyncLogger>
        <AsyncRoot level="info" includeLocation="false">
            <AppenderRef ref="console"/>
        </AsyncRoot>
　　</Loggers>
</Configuration>

https://blog.csdn.net/NEWCIH/article/details/76216606