Java：日志輸出JDK Logging、commons-logging、log4j、SLF4J、Logback

目錄

• • 使用 JDK Logging
  • 使用 commons-logging
  • 使用 log4j
  • SLF4J和Logback

package com.demo;

import java.util.logging.Logger;

public class Main {
    public static void main(String[] args) {
        Logger logger = Logger.getLogger(Main.class.getName());
        logger.info("info");
    }
}      

輸出

八月 06, 2020 5:39:42 下午 com.demo.Main main
資訊: info      

依賴

<dependency>
    <groupId>commons-logging</groupId>
    <artifactId>commons-logging</artifactId>
    <version>1.2</version>
</dependency>      

示例

package com.demo;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class Main {
    public static void main(String[] args) {
        Log log = LogFactory.getLog(Main.class);
        log.info("info");
    }
}
      

關系：

• Commons Logging 日志接口
• Log4j 日志實作

<!--commons-logging-->
<dependency>
    <groupId>commons-logging</groupId>
    <artifactId>commons-logging</artifactId>
    <version>1.2</version>
</dependency>

<!--log4j-->
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.13.3</version>
</dependency>

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.13.3</version>
</dependency>

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-jcl</artifactId>
    <version>2.13.3</version>
</dependency>      

日志配置 log4j2.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
    <Properties>
        <!-- 定義日志格式 -->
        <Property name="log.pattern">%d{MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{36}%n%msg%n%n</Property>
        <!-- 定義檔案名變量 -->
        <Property name="file.err.filename">log/err.log</Property>
        <Property name="file.err.pattern">log/err.%i.log.gz</Property>
    </Properties>

    <!-- 定義Appender，即目的地 -->
    <Appenders>
        <!-- 定義輸出到螢幕 -->
        <Console name="console" target="SYSTEM_OUT">
            <!-- 日志格式引用上面定義的log.pattern -->
            <PatternLayout pattern="${log.pattern}" />
        </Console>

        <!-- 定義輸出到檔案,檔案名引用上面定義的file.err.filename -->
        <RollingFile name="err" bufferedIO="true" fileName="${file.err.filename}" filePattern="${file.err.pattern}">
            <PatternLayout pattern="${log.pattern}" />
            <Policies>
                <!-- 根據檔案大小自動切割日志 -->
                <SizeBasedTriggeringPolicy size="1 MB" />
            </Policies>
            <!-- 保留最近10份 -->
            <DefaultRolloverStrategy max="10" />
        </RollingFile>
    </Appenders>

    <Loggers>
        <Root level="info">
            <!-- 對info級别的日志，輸出到console -->
            <AppenderRef ref="console" level="info" />
            <!-- 對error級别的日志，輸出到err，即上面定義的RollingFile -->
            <AppenderRef ref="err" level="error" />
        </Root>
    </Loggers>
</Configuration>      

使用示例

package com.demo;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class Main {
    public static void main(String[] args) {
        Log log = LogFactory.getLog(Main.class);
        log.info("info");
        log.error("error");
    }
}
      

關系

• SLF4J 日志接口
• Logback 日志的實作

Simple Logging Facade for Java (SLF4J)

<!--logback-->
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.7.30</version>
</dependency>

<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>1.2.3</version>
</dependency>

<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-core</artifactId>
    <version>1.2.3</version>
</dependency>      

配置檔案logback.xml

<?xml version="1.0" encoding="UTF-8"?>
<configuration>

    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
            <charset>utf-8</charset>
        </encoder>
        <file>log/output.log</file>
        <rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
            <fileNamePattern>log/output.log.%i</fileNamePattern>
        </rollingPolicy>
        <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
            <MaxFileSize>1MB</MaxFileSize>
        </triggeringPolicy>
    </appender>

    <root level="INFO">
        <appender-ref ref="CONSOLE" />
        <appender-ref ref="FILE" />
    </root>
</configuration>      

package com.demo;


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

public class Main {
    public static void main(String[] args) {
        Logger log = LoggerFactory.getLogger(Main.class);
        log.info("info");
        log.error("error");
    }
}
      

參考

https://www.liaoxuefeng.com/wiki/1252599548343744/1264738568571776