SpringBoot Log4j

最好是使用SpringBoot默认支持的Logback, 但是也有其他的业务需要使用Log4j.
SpringBoot版本:2.1.7.RELEASE , 1.5.19.RELEASE

使用实例

添加依赖

 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter</artifactId>
     <exclusions>
         <exclusion>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-logging</artifactId>
         </exclusion>
     </exclusions>
 </dependency>
 <dependency>
     <groupId>log4j</groupId>
     <artifactId>log4j</artifactId>
     <version>1.2.17</version>
 </dependency>
 <dependency>
     <groupId>org.slf4j</groupId>
     <artifactId>slf4j-log4j12</artifactId>
 </dependency>
 <dependency>
     <groupId>commons-logging</groupId>
     <artifactId>commons-logging</artifactId>
     <version>1.2</version>
 </dependency>

log4j xml配置

log4j.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j='http://jakarta.apache.org/log4j/'>
    <appender name="DEBUG_LOGGER" class="org.apache.log4j.ConsoleAppender">
        <!-- 设置是否在重新启动服务时，在原有日志的基础添加新日志 test dev -->
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} %5p [%F:%L]  - %m%n"/>
        </layout>
    </appender>
    <appender name="DRUID_LOGGER" class="org.apache.log4j.DailyRollingFileAppender">
        <param name="File" value="${webapp.root}/logs2/druid/druid.log"/>
        <param name="DatePattern" value="'.'yyyy-MM-dd-HH"/>
        <param name="encoding" value="utf-8"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss} %5p [%F:%L]  - %m%n"/>
        </layout>
    </appender>
    <logger name="druid.sql" additivity="false">
        <level value="DEBUG"/>
        <appender-ref ref="DRUID_LOGGER"/>
    </logger>
    <root>
        <level value="DEBUG"/>
        <appender-ref ref="DEBUG_LOGGER"/>
    </root>
</log4j:configuration>

代码配置

@SpringBootApplication
public class DemoApplication {
    static {
        //这里只是一个例子，根据具体情况进行修改
        System.setProperty("user.home", "/Users/admin/open/demo");
        System.setProperty("webapp.root", System.getProperty("user.home") + "/code");
        System.setProperty("org.springframework.boot.logging.LoggingSystem", Log4jLoggingSystem.class.getName());
    }
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

Log4jLoggingSystem

package com.example.demo.log;
import org.apache.log4j.xml.DOMConfigurator;
import org.springframework.boot.logging.LogFile;
import org.springframework.boot.logging.LoggingInitializationContext;
import org.springframework.boot.logging.Slf4JLoggingSystem;
import org.springframework.util.ResourceUtils;
import java.io.FileNotFoundException;
import java.net.URL;
/**
 * @author chenshun00@gmail.com
 * @since 2019-09-24 13:44
 */
public class Log4jLoggingSystem extends Slf4JLoggingSystem {
    public Log4jLoggingSystem(ClassLoader classLoader) {
        super(classLoader);
    }
    @Override
    public void initialize(LoggingInitializationContext initializationContext, String configLocation, LogFile logFile) {
        super.initialize(initializationContext, configLocation, logFile);
    }
    @Override
    protected void reinitialize(LoggingInitializationContext initializationContext) {
        try {
            String selfInitializationConfig = getSelfInitializationConfig();
            URL url = ResourceUtils.getURL(selfInitializationConfig);
            DOMConfigurator.configure(url);
        } catch (FileNotFoundException e) {
            throw new IllegalArgumentException(e);
        }
    }
    @Override
    protected void loadConfiguration(LoggingInitializationContext initializationContext, String location, LogFile logFile) {
        try {
            URL url = ResourceUtils.getURL(location == null ? initializationContext.getEnvironment().getProperty("logging.config") : location);
            DOMConfigurator.configure(url);
        } catch (FileNotFoundException e) {
            throw new IllegalArgumentException(e);
        }
    }
    @Override
    protected String[] getStandardConfigLocations() {
        return new String[]{"log4j.xml", "log4j-prod.xml", "log4j-test.xml", "log4j-dev.xml"};
    }
    @Override
    protected void loadDefaults(LoggingInitializationContext initializationContext, LogFile logFile) {
        try {
            URL url = ResourceUtils.getURL(initializationContext.getEnvironment().getProperty("logging.config"));
            DOMConfigurator.configure(url);
        } catch (FileNotFoundException e) {
            throw new IllegalArgumentException(e);
        }
    }
}