spring配置日志

参考:http://spring.io/blog/2009/12/04/logging-dependencies-in-spring


spring默认使用了commons-logging,在集成其它日志框架,slf4j使用了编译时绑定来代替运行时发现.它注定是更高效的(当然slf4j还可以使用占位符绑定等功能).下文介绍spring三种常用方案记录日志,推荐第三种
方案一:commons-logging+Log4J

1.依赖:

<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-context</artifactId>
	<version>${spring.version}</version>
</dependency>
<dependency>
	<groupId>log4j</groupId>
	<artifactId>log4j</artifactId>
	<version>1.2.17</version>
</dependency>

2.在classpath根目录添加log4j.properties或log4j.xml,关于开发的日志级别配置,调得太高,会漏到一些信息看不见,调得太低,输出得太多,看得眼花缭乱,在产品阶段甚至影响应用性能.我觉得开发时,默认(一般依赖也是用默认appender)给WARN,项目本身编写的代码可以给DEBUG,其它另外特别指定,以下是log4j.properties的一个例子:

log4j.rootCategory=WARN, stdout

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %t %c{2}:%L - %m%n

log4j.category.org.exam=DEBUG
log4j.category.org.springframework.beans.factory=INFO

根据log4j API(http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Category.html),Category已经过时,应使用Logger代替.而Logger是Category的子类,在Category的所有操作都可以在Logger上执行.以上的properties文件内容应改为

log4j.rootLogger=WARN, stdout

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %t %c{2}:%L - %m%n

log4j.logger.org.exam=DEBUG
log4j.logger.org.springframework.beans.factory=INFO

3.代码用法:

import org.apache.log4j.Logger;
public class UserService {
    final Logger logger = Logger.getLogger(UserService.class);
    public boolean save(){
        logger.error("虽然A喜欢我,但是我喜欢B");
        return true;
    }
}

方案二:slf4j+Log4J
1.先在spring排除commons-logging.再引入4个包:桥接包jcl-over-slf4j,SLF4J API包slf4j-api,绑定到Log4J的包slf4j-log4j12,Log4J实现包log4j12. 

<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>jcl-over-slf4j</artifactId>
	<version>1.7.7</version>
</dependency>
<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-log4j12</artifactId>
	<version>1.7.7</version>
</dependency>
<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-context</artifactId>
	<version>${spring.version}</version>
	<exclusions>
		<exclusion>
			<groupId>commons-logging</groupId>
			<artifactId>commons-logging</artifactId>
		</exclusion>
	</exclusions>
</dependency>

2.log4j配置同上.
3.代码用法:

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class UserService {
    final Logger logger = LoggerFactory.getLogger(UserService.class);
    public boolean save(){
        logger.error("虽然{}喜欢我,但是我喜欢{}","A","B");
        return true;
    }
}

方案三:slf4j+logback.其中,logback是slf4j原生的实现.

1.先引入logback-classic依赖,它会将其它依赖引入,再在spring排除commons-logging.

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.1.3</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>commons-logging</groupId>
                    <artifactId>commons-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

2.logback配置:查找顺序logback.groovy-->logback-test.xml-->logback.xml,详细配置还是参考文档http://logback.qos.ch/documentation.html.下面是logback.xml例子

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <appender name="console" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{yy.MM.dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>
    <logger name="org.exam" level="debug" />
    <logger name="org.springframework.beans.factory" level="info" />
    <root level="warn">
        <appender-ref ref="console"/>
    </root>
</configuration>

3.代码用法:同方案二一样