log4j2分层输出日志

在java mvc框架开发过程中，我们经常的将代码分为类似controller（控制层）、service（业务层）、rpc（远程接口调用层）、dao（数据层）等层级，如果将所有层级的日志全部都打到一个文件，一个是导致单个日志文件过大，另外不方便查看，所以下面考虑用log4j2根据不同层级生成对应的log文件：

1. maven配置

<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
		</dependency>
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-log4j12</artifactId>
		</dependency>
		<dependency>
			<groupId>org.apache.logging.log4j</groupId>
			<artifactId>log4j-1.2-api</artifactId>
			<version>2.10.0</version>
		</dependency>		    

2. log4j2配置文件

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" monitorInterval="30">
	<Properties>
		<!-- 文件输出格式 -->
		<Property name="pattern">%d{yyyy-MM-dd HH:mm:ss.SSS} |-%-5level [LOGID:%X{logId}] [%thread] %C#%M [%L] -| %msg%n</Property>
		<Property name="filePath">/export/Logs/Domains/myapp</Property>
	</Properties>

	<Appenders>
		<Console name="console" target="system_out">
			<PatternLayout pattern="${pattern}" />
		</Console>
		<RollingRandomAccessFile name="rpcFile" fileName="${filePath}/rpc.log" filePattern="${filePath}/rpc-%d{yyyy-MM-dd}.log">
			<PatternLayout pattern="${pattern}"/>
			<Policies>
				<TimeBasedTriggeringPolicy modulate="true" interval="1"/>
			</Policies>
		</RollingRandomAccessFile>

		<RollingRandomAccessFile name="serviceFile" fileName="${filePath}/service.log" filePattern="${filePath}/service-%d{yyyy-MM-dd}.log">
			<PatternLayout pattern="${pattern}"/>
			<Policies>
				<TimeBasedTriggeringPolicy modulate="true" interval="1"/>
			</Policies>
		</RollingRandomAccessFile>
		<RollingRandomAccessFile name="controllerFile" fileName="${filePath}/controller.log" filePattern="${filePath}/controller-%d{yyyy-MM-dd}.log">
			<PatternLayout pattern="${pattern}"/>
			<Policies>
				<TimeBasedTriggeringPolicy modulate="true" interval="1"/>
			</Policies>
		</RollingRandomAccessFile>

	</Appenders>

	<Loggers>
		<!--过滤信息-->
		<logger name="org.springframework" level="WARN"></logger>
		<logger name="RPC" level="INFO" >
			<AppenderRef ref="rpcFile" />
		</logger>
		<logger name="SERVICE" level="INFO" >
			<AppenderRef ref="serviceFile" />
		</logger>
		<logger name="CONTROLLER" level="INFO" >
			<AppenderRef ref="controllerFile" />
		</logger>
		<Root level="INFO">
			<AppenderRef ref="console" />
			<AppenderRef ref="exceptionFile" />
		</Root>
	</Loggers>

</Configuration>

3. 输出日志工具类

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

public class LogUtil {

	/**
	 * RPC层日志记录
	 */
	public static final Logger RPC = LoggerFactory.getLogger("RPC");

	/**
	 * Service业务层日志记录
	 */
	public static final Logger SERVICE = LoggerFactory.getLogger("SERVICE");

	/**
	 * Controller业务层日志记录
	 */
	public static final Logger CONTROLLER = LoggerFactory.getLogger("CONTROLLER");

}

4. 输出日志

LogUtil.CONTROLLER.error("error message={}", e);
LogUtil.SERVICE.warn("warn message={}", msg);
....