系统复习Java日志体系

一，我们采用硬编码体验一下几个使用比较多的日志

分别导入几种日志的 jar 包

XML 复制代码

<?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>com.fll</groupId>
  <artifactId>log-system-study</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>log-system-study</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <!--  ===  log4j1 相关jar包  ====  -->

    <!-- 单独导入 log4j1 -->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>

    <!--  ===  log4j2 相关jar包  ===  -->

    <!-- 单独导入 log4j2 -->
    <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-core</artifactId>
      <version>2.13.3</version>
    </dependency>

    <!--  === logback 相关jar包  ====  -->

    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.2.4</version>
    </dependency>

    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-core</artifactId>
      <version>1.2.4</version>
    </dependency>

  </dependencies>

  <build>

  </build>

</project>

java 复制代码

package com.fll;


import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.util.ContextInitializer;
import ch.qos.logback.core.joran.spi.JoranException;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.spi.ExtendedLogger;
import org.junit.Test;

import java.net.URL;
import java.util.logging.Logger;


public class LoggerTest {

    /**
     * java自带的日志工具 
     * java.util.logging.Logger
     */
    @Test
    public void julLogger() {
        Logger logger = Logger.getLogger("julLogger");
        //System.setProperty("-Djava.util.logging.config.file", "classpath:/logging.properties");
        //logger.setLevel(Level.FINE);
        logger.info("julLogger Hello World!");
//运行结果  显示红色
//七月 30, 2024 10:51:38 上午 com.fll.LoggerTest julLogger
//信息: julLogger Hello World!
    }

    /**
     * log4j1
     */
    @Test
    public void log4JLogger(){
        org.apache.log4j.Logger log4JLogger = org.apache.log4j.Logger.getLogger("log4JLogger");
        log4JLogger.info("log4J_1_Logger Hello World!");
//运行结果
//[log4j_1] 2024-07-30 10:55:29,017 INFO [log4J_1_Logger] - log4J_1_Logger Hello World!
    }

    /**
     * log4j2
     */
    @Test
    public void log4J_2_Logger(){
        ExtendedLogger logger= LogManager.getContext().getLogger("log4J_2_Logger");
        logger.info("log4J_2_Logger Hello World!");
//运行结果
//[log4j_2] line=41 10:55:50.050 [main]INFO  - log4J_2_Logger Hello World!
    }

    /**
     * logback
     */
    @Test
    public void logBackLogger(){

        // Here we create context
        LoggerContext loggerContext = new LoggerContext();

        //创建一个LoggerContext的初始化器,该初始化器可以通过configureByResource()方法,
        //使用指定的配置(xml，或者 properties)对LoggerContext实例进行初始化
        // Initializer is used to enrich context with details
        ContextInitializer contextInitializer = new ContextInitializer(loggerContext);
        try {
            //获取我们的配置文件
            // Get a configuration file from classpath
            URL configurationUrl = Thread.currentThread()
                        .getContextClassLoader().getResource("logback.xml");

            if (configurationUrl == null) {
                throw new IllegalStateException
                          ("Unable to find custom logback configuration file");
            }

            // 解析配置文件，将解析到的配置设置给 LoggerContext
            // Ask context initializer to load configuration into context
            contextInitializer.configureByResource(configurationUrl);

            // Here we get logger from context
            ch.qos.logback.classic.Logger logger = 
                          loggerContext.getLogger("logBackLogger");

            logger.info("logBackLogger Hello World!");
//运行结果
//[logback] 2024-07-30 10:57:03 [main] INFO  logBackLogger - logBackLogger Hello World!

        } catch (JoranException e) {
            throw new RuntimeException("Unable to configure logger", e);
        }


    }

    @Test
    public void logBackLogger1(){

        // Here we create context
        LoggerContext loggerContext = new LoggerContext();
        // Initializer is used to enrich context with details
        ContextInitializer contextInitializer = new ContextInitializer(loggerContext);
        try {

            //autoConfig 方法中 会先调用 findURLOfDefaultConfigurationFile()
            //获取一个默认的配置文件，

            // 然后调用configureByResource 对 loggerContext进行初始化
            // findURLOfDefaultConfigurationFile 逻辑是先获取环境变量 
            //logback.configurationFile

            // 配置的文件，找不到再找 logback-test.xml ，logback.groovy ， logback.xml
            contextInitializer.autoConfig();

            // Here we get logger from context
            ch.qos.logback.classic.Logger logger =     
                         loggerContext.getLogger("logBackLogger");
            logger.info("logBackLogger Hello World!");

//运行结果
//[logback] 2024-07-30 10:57:51 [main] INFO  logBackLogger - logBackLogger Hello World!
        } catch (JoranException e) {
            throw new RuntimeException("Unable to configure logger", e);
        }


    }

}

log4j的配置文件 log4j.properties

java 复制代码

log4j.rootLogger=info, stdout

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=[log4j_1] %d %p [%c] - %m%n

log4j2的配置文件 log4j2.xml

XML 复制代码

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

	<appenders>
	
		<Console name="Console" target="SYSTEM_OUT">
			<PatternLayout pattern="[log4j_2] line=%L %d{HH:mm:ss.sss} [%t]%highlight{%-5level} - %msg%n"/>
		</Console>
		
		<!-- <Console name="Console" target="SYSTEM_0UT"> -->
		<!-- <PatternLayout pattern="file=%c line=%L %dHH:mm:ss.sss}[%t]%highlight{%-5level} %logger{36}-%msg%n"/> -->
		<!-- </Console> -->
	</appenders>
	
	<loggers>
		<root level="debug">
			<appender-ref ref="Console"/>
		</root>
	</loggers>
	
</configuration>

java.util.logging.Logger 配置文件 logging.properties

java 复制代码

.level=WARNING

handlers=java.util.logging.ConsoleHandler

java.util.logging.ConsoleHandler.level=WARNING
java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter

logback的配置文件 logback.xml

XML 复制代码

<configuration>

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

    <root level="debug">
        <appender-ref ref="STDOUT" />
    </root>

</configuration>

二、采用 commons-logging 动态选用日志

<!--  ===  commons-logging 相关jar包  ==  -->
<dependency>
  <groupId>commons-logging</groupId>
  <artifactId>commons-logging</artifactId>
  <version>1.2</version>
</dependency>

先只导入commons-logging.jar不导入其他的日志包

java 复制代码

package com.fll;

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

public class CommonLoggingTest {

    @Test
    public void commonLogging(){
        Log logger = LogFactory.getLog("commonLogging");
        logger.info("commonLogging Hello World!");
    }

}

可以看到运行结果：日志打印采用的是

class org.apache.commons.logging.impl.Jdk14Logger

内部封装的是 java.util.logging.Logger

除了commons-logging之外再导入 log4j1的 jar 包

XML 复制代码

<!--  ===  commons-logging 相关jar包  ==  -->
<dependency>
  <groupId>commons-logging</groupId>
  <artifactId>commons-logging</artifactId>
  <version>1.2</version>
</dependency>

<!-- 单独导入 log4j1 -->
<dependency>
  <groupId>log4j</groupId>
  <artifactId>log4j</artifactId>
  <version>1.2.17</version>
</dependency>

可以看到运行结果：日志打印采用的是

class org.apache.commons.logging.impl.Log4JLogger