log4 slf4j使用（一）

• 目标
  ·slf4j接口+log4j实现，完成记录日志
  ·lombok 使用@Slf4j注解，快速开发，免写 private static final Logger log = LoggerFactory.getLogger(MainTest.class);

• code
  测试程序

package com.mvp.www;

import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @classDesc: 功能描述: slf4j和log4j/log4j2的结合，
 * log4j使用log4j.properties，log4j2使用log4j2.yml/log4j2-test.xml(正式项目中使用一种，同时调试两种，文件冲突，clean一下)
 */
@Slf4j
public class MainTest {
//    private static final Logger log = LoggerFactory.getLogger(MainTest.class);

    @Test
    public void test() {
        log.info("MainTest.test,Hello={}", "Hello");
        log.error("MainTest.test,Num={}", 100);
        log.warn("MainTest.test,Clear={}", "This error is clear");
    }
}

lombok maven依赖

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.12</version>
        </dependency>

junit单元测试maven依赖

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
        </dependency>

一) slf4j + log4j
maven依赖

        <!--slf4j + log4j-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.30</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <!--2020稳定版本1.7.30, 2.0在测试，和slf4j-api保持一致-->
            <version>1.7.30</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <!--1.x版本到1.2.17不再更新-->
            <version>1.2.17</version>
        </dependency>

log4j的配置文件log4j.properties

# Set root logger level to DEBUG and its only appender to A1.
log4j.rootLogger=DEBUG, A1

# A1 is set to be a ConsoleAppender.
log4j.appender.A1=org.apache.log4j.ConsoleAppender

# A1 uses PatternLayout.
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

1.2.17， 1.x的截止版本

二）slf4j + log4j2
maven依赖

        <!--slf4j + log4j2-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.30</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.12.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.12.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-slf4j-impl</artifactId>
            <version>2.12.1</version>
        </dependency>

配置文件log4j2-test.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
        </Console>
    </Appenders>
    <Loggers>
        <Root level="info">
            <AppenderRef ref="Console"/>
        </Root>
    </Loggers>
</Configuration>

读取默认配置文件

• 官方文档
  ·http://logging.apache.org/log4j/2.x/
  ·http://logging.apache.org/log4j/1.2/