码迷，mamicode.com
首页 > 其他好文 > 详细

Slf4j初探

时间：2020-05-30 10:49:53      阅读：50      评论：0      收藏：0      [点我收藏+]

标签：factor   enc   bridge   依赖   snapshot   绑定   测试   ring   tar   

1.新建module,slf4j-demo

2.pom.xml添加依赖

<?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">
    <parent>
        <artifactId>log-study</artifactId>
        <groupId>com.lxcourse</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>sfl4j-demo</artifactId>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.28</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.28</version>
        </dependency>
    </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

3.编写测试类Slf4jDemo.java

package com.lxcourse.slf4j;

import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author doubledumbao
 * Slf4j快速入门
 */
public class Slf4jDemo {

    public static final Logger LOGGER = LoggerFactory.getLogger(Slf4jDemo.class);

    @Test
    public  void testQuick(){
        LOGGER.error("error");
        LOGGER.warn("warn");
        LOGGER.info("info");
        LOGGER.debug("debug");
        LOGGER.trace("trace");
        String name = "lxcourse";
        String url = "https://www.lxcourse.cn";
        LOGGER.info("网站:{}，网址:{}",name,url);

        try {
            int a = 10/0;
        } catch (Exception e) {
            LOGGER.error("发生异常{}","hello",e);
        }
    }

}

技术图片

4.slf4j绑定logback

pom.xml

<?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">
    <parent>
        <artifactId>log-study</artifactId>
        <groupId>com.lxcourse</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>sfl4j-demo</artifactId>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.28</version>
        </dependency>
        <!--
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.28</version>
        </dependency>
        -->
        <!--   logback日志     -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
    </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

5.slf4j绑定slf4j-nop

<?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">
    <parent>
        <artifactId>log-study</artifactId>
        <groupId>com.lxcourse</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>sfl4j-demo</artifactId>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.28</version>
        </dependency>
        <!-- slf4j 内置简单日志
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.27</version>
        </dependency>
        -->
        <!--   logback日志
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
        -->
        <!-- 绑定为NOP，静默丢弃所有日志记录。       -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-nop</artifactId>
            <version>1.7.28</version>
        </dependency>

    </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

6.slf4j绑定log4j

pom.xml

<?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">
    <parent>
        <artifactId>log-study</artifactId>
        <groupId>com.lxcourse</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>sfl4j-demo</artifactId>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.28</version>
        </dependency>
        <!-- slf4j 内置简单日志
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.27</version>
        </dependency>
        -->
        <!--   logback日志
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
        -->
        <!-- 绑定为NOP，静默丢弃所有日志记录。
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-nop</artifactId>
            <version>1.7.28</version>
        </dependency>
         -->
        <!--  绑定log4j 1.2版（一种广泛使用的日志记录框架）。您还需要将log4j.jar放在类路径上。      -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.28</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

添加log4j.properties

log4j.rootLogger=trace,console

# 指定控制台日志输出的appender
log4j.appender.console = org.apache.log4j.ConsoleAppender
log4j.appender.console.layout = org.apache.log4j.PatternLayout
log4j.appender.console.layout.conversionPattern = [%-5p] %r %C %M %d{yyyy-MM-dd HH:mm:ss} %m%n

7.slf4j绑定jdk14

<?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">
    <parent>
        <artifactId>log-study</artifactId>
        <groupId>com.lxcourse</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>sfl4j-demo</artifactId>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.28</version>
        </dependency>
        <!-- slf4j 内置简单日志
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.27</version>
        </dependency>
        -->
        <!--   logback日志
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
        -->
        <!-- 绑定为NOP，静默丢弃所有日志记录。
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-nop</artifactId>
            <version>1.7.28</version>
        </dependency>
         -->
        <!--  绑定log4j 1.2版（一种广泛使用的日志记录框架）。您还需要将log4j.jar放在类路径上。
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.28</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
         -->
        <!-- 绑定JUL日志 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-jdk14</artifactId>
            <version>1.7.28</version>
        </dependency>

    </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

8.使用slf4j的日志绑定流程:

  1. 添加slf4j-api的依赖

  2. 使用slf4j的API在项目中进行统一的日志记录

  3. 绑定具体的日志实现框架

    3.1 绑定已经实现了slf4j的日志框架,直接添加对应依赖

    3.2 绑定没有实现slf4j的日志框架,先添加日志的适配器,再添加实现类的依赖

  4. slf4j有且仅有一个日志实现框架的绑定(如果出现多个默认使用第一个依赖日志实现)

9.slf4j桥接器

比如原来项目中使用的log4j，依赖如下：

<?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">
    <parent>
        <artifactId>log-study</artifactId>
        <groupId>com.lxcourse</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>slf4j-bridge-demo</artifactId>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>


</project>

log4j.properties

log4j.rootLogger=trace,console

# 指定控制台日志输出的appender
log4j.appender.console = org.apache.log4j.ConsoleAppender
log4j.appender.console.layout = org.apache.log4j.PatternLayout
log4j.appender.console.layout.conversionPattern = [%-5p] %r %C %M %d{yyyy-MM-dd HH:mm:ss} %m%n

测试代码：

package com.lxcourse.log4j;

import org.apache.log4j.Logger;
import org.junit.Test;

/**
 * @author doubledumbao
 */
public class Log4jDemo {

    public static Logger LOGGER = Logger.getLogger(Log4jDemo.class);

    @Test
    public void testQuick(){
        LOGGER.error("error");
        LOGGER.warn("warn");
        LOGGER.info("info");
        LOGGER.debug("debug");
        LOGGER.trace("trace");
    }
}

现在将日志框架替换为slf4j+logback

pom.xml

<?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">
    <parent>
        <artifactId>log-study</artifactId>
        <groupId>com.lxcourse</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>slf4j-bridge-demo</artifactId>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!-- 注释掉log4j的依赖
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        -->
        <!--  slf4j的依赖  -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.28</version>
        </dependency>
        <!--  logback的依赖      -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
        <!--   log4j桥接器     -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>log4j-over-slf4j</artifactId>
            <version>1.7.28</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

注意问题:

  1. jcl-over-slf4j.jar和 slf4j-jcl.jar不能同时部署。前一个jar文件将导致JCL将日志系统的选择委托给 SLF4J，后一个jar文件将导致SLF4J将日志系统的选择委托给JCL，从而导致无限循环。

  2. log4j-over-slf4j.jar和slf4j-log4j12.jar不能同时出现

  3. jul-to-slf4j.jar和slf4j-jdk14.jar不能同时出现

  4. 所有的桥接都只对Logger日志记录器对象有效，如果程序中调用了内部的配置类或者是Appender,Filter等对象，将无法产生效果。

10.SLF4J原理解析

  1. SLF4J通过LoggerFactory加载日志具体的实现对象。
  2. LoggerFactory在初始化的过程中，会通过performInitialization()方法绑定具体的日志实现。
  3. 在绑定具体实现的时候，通过类加载器，加载org/slf4j/impl/StaticLoggerBinder.class
  4. 所以，只要是一个日志实现框架，在org.slf4j.impl包中提供一个自己的StaticLoggerBinder类，在其中提供具体日志实现的LoggerFactory就可以被SLF4J所加载

Slf4j初探

标签：factor   enc   bridge   依赖   snapshot   绑定   测试   ring   tar   

原文地址：https://www.cnblogs.com/zhaoran8775/p/12990755.html
踩
(0)
赞
(0)
   
举报
评论 一句话评论（0）
登录后才能评论！
分享档案
更多>
2021年07月29日 (22)
2021年07月28日 (40)
2021年07月27日 (32)
2021年07月26日 (79)
2021年07月23日 (29)
2021年07月22日 (30)
2021年07月21日 (42)
2021年07月20日 (16)
2021年07月19日 (90)
2021年07月16日 (35)
周排行
mamicode.com排行更多图片
更多
友情链接
兰亭集智   国之画   百度统计   站长统计   阿里云   chrome插件   新版天听网
关于我们 - 联系我们 - 留言反馈
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码！