将应用的log4j换成logback

考虑到log4j很久不更新、性能相对弱，以及一些项目本身的原因，经过较为谨慎的考虑，决定改用logback。迁移还是比较顺利的，花了1个小时左右就搞定了，做个简单的笔记。

(1) 首先去掉所有log4j相关的依赖，主要有：

<dependency>
  <groupId>log4j</groupId>
  <artifactId>log4j</artifactId>
</dependency>

以及：

<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-log4j12</artifactId>
</dependency>

(2) 为项目添加以下依赖：

<!-- logback日志配置开始 -->
<dependency>
  <groupId>ch.qos.logback</groupId>
  <artifactId>logback-core</artifactId>
</dependency>
<dependency>
  <groupId>ch.qos.logback</groupId>
  <artifactId>logback-access</artifactId>
</dependency>
<dependency>
  <groupId>ch.qos.logback</groupId>
  <artifactId>logback-classic</artifactId>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>log4j-over-slf4j</artifactId>
</dependency>
<!-- logback日志配置结束 -->

(3) 删除项目/src/main/resources目录下的log4j.properties，并在该目录添加logback.xml文件，logback.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
	<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
		<Target>System.out</Target>
		<encoder>
			<pattern>%date [%level] [%thread] %logger{80} [%file : %line] %msg%n</pattern>
		</encoder>
	</appender>
	<appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
		<encoder>
			<pattern>%date [%level] [%thread] %logger{80} [%file : %line] %msg%n</pattern>
		</encoder>
		<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
			<fileNamePattern>${catalina.home}/logs/yzf/sql%d{yyyy-MM-dd}.log</fileNamePattern>
			<!-- 保留 30天数据，默认无限-->
			<MaxHistory>30</MaxHistory>
		</rollingPolicy>
	</appender>
	<logger name="org.springframework" level="INFO" />
	<logger name="org.apache" level="INFO" />

	<logger name="com.itmuch" level="WARN" />
	<root level="INFO">
		<appender-ref ref="CONSOLE" />
		<appender-ref ref="FILE" />
	</root>
</configuration>

TIPS

(1) log4j-over-slf4j与slf4j-log4j12不能共存，可能会引发异常，详见http://www.tuicool.com/articles/INveIf 。

(2) slf4j-api、slf4j-log4j12以及log4j之间的关系http://blog.csdn.net/tengdazhang770960436/article/details/18006127

(3) 参考文档：http://blog.csdn.net/chenminghe271/article/details/38682493