桥接器：用于将第三方库中的日志系统由JCL，log4j和JUL重定向到slf4j中，以便日志的统一管理。

实例：将spring的日志由JCL重定向到slf4j

1）spring配置JCL+log4j

-pom.xml

    <dependencies><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>3.2.13.RELEASE</version></dependency><dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>1.2.17</version></dependency></dependencies>

-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="console" class="org.apache.log4j.ConsoleAppender"><layout class="org.apache.log4j.PatternLayout"><param name="ConversionPattern"value="[%d{yyyy-MM-dd HH:mm:ss,SSS\} %-5p] [%t] %c{2\} - %m%n" />       </layout></appender><root><priority value="INFO"/><appender-ref ref="console"/></root></log4j:configuration>

-ApplicationContext-Bean.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsd"><bean id="person" class="com.siyuan.test.slf4j.entity.Person"><property name="name" value="siyuan"/></bean></beans>

-Person.java

package com.siyuan.test.slf4j.entity;public class Person {private String name;public Person() {}public String getName() {return name;}public void setName(String name) {this.name = name;}}

-BridgeTest.java

package com.siyuan.test.slf4j.bridge;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import com.siyuan.test.slf4j.entity.Person;public class BridgeTest {public static void main(String[] args) {ApplicationContext ctxt = new ClassPathXmlApplicationContext("ApplicationContext-Bean.xml");System.out.println(ctxt.getBean("person"));System.out.println(((Person) ctxt.getBean("person")).getName());}}

-运行结果

[2015-06-03 00:01:40,221 INFO ] [main] support.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@19c247a0: startup date [Wed Jun 03 00:01:40 CST 2015]; root of context hierarchy
[2015-06-03 00:01:40,272 INFO ] [main] xml.XmlBeanDefinitionReader - Loading XML bean definitions from class path resource [ApplicationContext-Bean.xml]
[2015-06-03 00:01:40,397 INFO ] [main] support.DefaultListableBeanFactory - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@420f9c40: defining beans [person]; root of factory hierarchy
com.siyuan.test.slf4j.entity.Person@276a38b5
siyuan

2）重定向到slf4j

-去除JCL+log4j，加入桥接器+logback

pom.xml

<dependencies><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>3.2.13.RELEASE</version><exclusions><exclusion><artifactId>commons-logging</artifactId><groupId>commons-logging</groupId></exclusion></exclusions></dependency><dependency><groupId>org.slf4j</groupId><artifactId>jcl-over-slf4j</artifactId><version>1.7.12</version></dependency><dependency><groupId>ch.qos.logback</groupId><artifactId>logback-classic</artifactId><version>1.1.3</version></dependency></dependencies>

logback-test.xml

<?xml version="1.0" encoding="UTF-8"?>
<configuration><appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"><encoder><pattern>%date %level [%thread] %logger{10} [%file:%line] %msg%n</pattern></encoder></appender><root level="debug"><appender-ref ref="STDOUT" /></root></configuration>

BridgeTest运行结果

2015-06-03 00:07:14,556 DEBUG [main] o.s.c.e.StandardEnvironment [MutablePropertySources.java:108] Adding [systemProperties] PropertySource with lowest search precedence
2015-06-03 00:07:14,563 DEBUG [main] o.s.c.e.StandardEnvironment [MutablePropertySources.java:108] Adding [systemEnvironment] PropertySource with lowest search precedence
2015-06-03 00:07:14,564 DEBUG [main] o.s.c.e.StandardEnvironment [AbstractEnvironment.java:126] Initialized StandardEnvironment with PropertySources [systemProperties,systemEnvironment]
2015-06-03 00:07:14,568 INFO [main] o.s.c.s.ClassPathXmlApplicationContext [AbstractApplicationContext.java:512] Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@b6e39f: startup date [Wed Jun 03 00:07:14 CST 2015]; root of context hierarchy
2015-06-03 00:07:14,606 DEBUG [main] o.s.c.e.StandardEnvironment [MutablePropertySources.java:108] Adding [systemProperties] PropertySource with lowest search precedence
2015-06-03 00:07:14,607 DEBUG [main] o.s.c.e.StandardEnvironment [MutablePropertySources.java:108] Adding [systemEnvironment] PropertySource with lowest search precedence
2015-06-03 00:07:14,607 DEBUG [main] o.s.c.e.StandardEnvironment [AbstractEnvironment.java:126] Initialized StandardEnvironment with PropertySources [systemProperties,systemEnvironment]
2015-06-03 00:07:14,617 INFO [main] o.s.b.f.x.XmlBeanDefinitionReader [XmlBeanDefinitionReader.java:316] Loading XML bean definitions from class path resource [ApplicationContext-Bean.xml]
2015-06-03 00:07:14,620 DEBUG [main] o.s.b.f.x.DefaultDocumentLoader [DefaultDocumentLoader.java:72] Using JAXP provider [com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl]
2015-06-03 00:07:14,644 DEBUG [main] o.s.b.f.x.PluggableSchemaResolver [PluggableSchemaResolver.java:140] Loading schema mappings from [META-INF/spring.schemas]
2015-06-03 00:07:14,648 DEBUG [main] o.s.b.f.x.PluggableSchemaResolver [PluggableSchemaResolver.java:146] Loaded schema mappings: {http://www.springframework.org/schema/util/spring-util.xsd=org/springframework/beans/factory/xml/spring-util-3.2.xsd, http://www.springframework.org/schema/jee/spring-jee-3.2.xsd=org/springframework/ejb/config/spring-jee-3.2.xsd, http://www.springframework.org/schema/beans/spring-beans-3.1.xsd=org/springframework/beans/factory/xml/spring-beans-3.1.xsd, http://www.springframework.org/schema/task/spring-task.xsd=org/springframework/scheduling/config/spring-task-3.2.xsd, http://www.springframework.org/schema/cache/spring-cache.xsd=org/springframework/cache/config/spring-cache-3.2.xsd, http://www.springframework.org/schema/aop/spring-aop-3.0.xsd=org/springframework/aop/config/spring-aop-3.0.xsd, http://www.springframework.org/schema/task/spring-task-3.1.xsd=org/springframework/scheduling/config/spring-task-3.1.xsd, http://www.springframework.org/schema/aop/spring-aop-2.0.xsd=org/springframework/aop/config/spring-aop-2.0.xsd, http://www.springframework.org/schema/tool/spring-tool-2.5.xsd=org/springframework/beans/factory/xml/spring-tool-2.5.xsd, http://www.springframework.org/schema/beans/spring-beans.xsd=org/springframework/beans/factory/xml/spring-beans-3.2.xsd, http://www.springframework.org/schema/jee/spring-jee-2.5.xsd=org/springframework/ejb/config/spring-jee-2.5.xsd, http://www.springframework.org/schema/tool/spring-tool-3.1.xsd=org/springframework/beans/factory/xml/spring-tool-3.1.xsd, http://www.springframework.org/schema/jee/spring-jee-3.1.xsd=org/springframework/ejb/config/spring-jee-3.1.xsd, http://www.springframework.org/schema/aop/spring-aop.xsd=org/springframework/aop/config/spring-aop-3.2.xsd, http://www.springframework.org/schema/context/spring-context-3.2.xsd=org/springframework/context/config/spring-context-3.2.xsd, http://www.springframework.org/schema/util/spring-util-3.2.xsd=org/springframework/beans/factory/xml/spring-util-3.2.xsd, http://www.springframework.org/schema/beans/spring-beans-2.0.xsd=org/springframework/beans/factory/xml/spring-beans-2.0.xsd, http://www.springframework.org/schema/lang/spring-lang-3.2.xsd=org/springframework/scripting/config/spring-lang-3.2.xsd, http://www.springframework.org/schema/beans/spring-beans-3.0.xsd=org/springframework/beans/factory/xml/spring-beans-3.0.xsd, http://www.springframework.org/schema/cache/spring-cache-3.2.xsd=org/springframework/cache/config/spring-cache-3.2.xsd, http://www.springframework.org/schema/task/spring-task-3.0.xsd=org/springframework/scheduling/config/spring-task-3.0.xsd, http://www.springframework.org/schema/context/spring-context-2.5.xsd=org/springframework/context/config/spring-context-2.5.xsd, http://www.springframework.org/schema/tool/spring-tool-3.0.xsd=org/springframework/beans/factory/xml/spring-tool-3.0.xsd, http://www.springframework.org/schema/util/spring-util-2.5.xsd=org/springframework/beans/factory/xml/spring-util-2.5.xsd, http://www.springframework.org/schema/tool/spring-tool-2.0.xsd=org/springframework/beans/factory/xml/spring-tool-2.0.xsd, http://www.springframework.org/schema/lang/spring-lang.xsd=org/springframework/scripting/config/spring-lang-3.2.xsd, http://www.springframework.org/schema/lang/spring-lang-2.5.xsd=org/springframework/scripting/config/spring-lang-2.5.xsd, http://www.springframework.org/schema/aop/spring-aop-3.2.xsd=org/springframework/aop/config/spring-aop-3.2.xsd, http://www.springframework.org/schema/jee/spring-jee-3.0.xsd=org/springframework/ejb/config/spring-jee-3.0.xsd, http://www.springframework.org/schema/jee/spring-jee-2.0.xsd=org/springframework/ejb/config/spring-jee-2.0.xsd, http://www.springframework.org/schema/context/spring-context-3.1.xsd=org/springframework/context/config/spring-context-3.1.xsd, http://www.springframework.org/schema/util/spring-util-3.1.xsd=org/springframework/beans/factory/xml/spring-util-3.1.xsd, http://www.springframework.org/schema/lang/spring-lang-3.1.xsd=org/springframework/scripting/config/spring-lang-3.1.xsd, http://www.springframework.org/schema/cache/spring-cache-3.1.xsd=org/springframework/cache/config/spring-cache-3.1.xsd, http://www.springframework.org/schema/context/spring-context.xsd=org/springframework/context/config/spring-context-3.2.xsd, http://www.springframework.org/schema/jee/spring-jee.xsd=org/springframework/ejb/config/spring-jee-3.2.xsd, http://www.springframework.org/schema/aop/spring-aop-2.5.xsd=org/springframework/aop/config/spring-aop-2.5.xsd, http://www.springframework.org/schema/beans/spring-beans-3.2.xsd=org/springframework/beans/factory/xml/spring-beans-3.2.xsd, http://www.springframework.org/schema/aop/spring-aop-3.1.xsd=org/springframework/aop/config/spring-aop-3.1.xsd, http://www.springframework.org/schema/task/spring-task-3.2.xsd=org/springframework/scheduling/config/spring-task-3.2.xsd, http://www.springframework.org/schema/context/spring-context-3.0.xsd=org/springframework/context/config/spring-context-3.0.xsd, http://www.springframework.org/schema/tool/spring-tool.xsd=org/springframework/beans/factory/xml/spring-tool-3.2.xsd, http://www.springframework.org/schema/util/spring-util-3.0.xsd=org/springframework/beans/factory/xml/spring-util-3.0.xsd, http://www.springframework.org/schema/util/spring-util-2.0.xsd=org/springframework/beans/factory/xml/spring-util-2.0.xsd, http://www.springframework.org/schema/lang/spring-lang-3.0.xsd=org/springframework/scripting/config/spring-lang-3.0.xsd, http://www.springframework.org/schema/lang/spring-lang-2.0.xsd=org/springframework/scripting/config/spring-lang-2.0.xsd, http://www.springframework.org/schema/tool/spring-tool-3.2.xsd=org/springframework/beans/factory/xml/spring-tool-3.2.xsd, http://www.springframework.org/schema/beans/spring-beans-2.5.xsd=org/springframework/beans/factory/xml/spring-beans-2.5.xsd}
2015-06-03 00:07:14,650 DEBUG [main] o.s.b.f.x.PluggableSchemaResolver [PluggableSchemaResolver.java:118] Found XML schema [http://www.springframework.org/schema/beans/spring-beans.xsd] in classpath: org/springframework/beans/factory/xml/spring-beans-3.2.xsd
2015-06-03 00:07:14,719 DEBUG [main] o.s.b.f.x.DefaultBeanDefinitionDocumentReader [DefaultBeanDefinitionDocumentReader.java:99] Loading bean definitions
2015-06-03 00:07:14,739 DEBUG [main] o.s.b.f.x.XmlBeanDefinitionReader [AbstractBeanDefinitionReader.java:216] Loaded 1 bean definitions from location pattern [ApplicationContext-Bean.xml]
2015-06-03 00:07:14,739 DEBUG [main] o.s.c.s.ClassPathXmlApplicationContext [AbstractApplicationContext.java:542] Bean factory for org.springframework.context.support.ClassPathXmlApplicationContext@b6e39f: org.springframework.beans.factory.support.DefaultListableBeanFactory@67eb366: defining beans [person]; root of factory hierarchy
2015-06-03 00:07:14,756 DEBUG [main] o.s.c.s.ClassPathXmlApplicationContext [AbstractApplicationContext.java:809] Unable to locate MessageSource with name 'messageSource': using default [org.springframework.context.support.DelegatingMessageSource@2c09505f]
2015-06-03 00:07:14,760 DEBUG [main] o.s.c.s.ClassPathXmlApplicationContext [AbstractApplicationContext.java:833] Unable to locate ApplicationEventMulticaster with name 'applicationEventMulticaster': using default [org.springframework.context.event.SimpleApplicationEventMulticaster@205ddb6e]
2015-06-03 00:07:14,761 INFO [main] o.s.b.f.s.DefaultListableBeanFactory [DefaultListableBeanFactory.java:603] Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@67eb366: defining beans [person]; root of factory hierarchy
2015-06-03 00:07:14,762 DEBUG [main] o.s.b.f.s.DefaultListableBeanFactory [DefaultSingletonBeanRegistry.java:215] Creating shared instance of singleton bean 'person'
2015-06-03 00:07:14,762 DEBUG [main] o.s.b.f.s.DefaultListableBeanFactory [AbstractAutowireCapableBeanFactory.java:432] Creating instance of bean 'person'
2015-06-03 00:07:14,781 DEBUG [main] o.s.b.f.s.DefaultListableBeanFactory [AbstractAutowireCapableBeanFactory.java:506] Eagerly caching bean 'person' to allow for resolving potential circular references
2015-06-03 00:07:14,816 DEBUG [main] o.s.b.f.s.DefaultListableBeanFactory [AbstractAutowireCapableBeanFactory.java:460] Finished creating instance of bean 'person'
2015-06-03 00:07:14,817 DEBUG [main] o.s.c.s.ClassPathXmlApplicationContext [AbstractApplicationContext.java:860] Unable to locate LifecycleProcessor with name 'lifecycleProcessor': using default [org.springframework.context.support.DefaultLifecycleProcessor@3801318b]
2015-06-03 00:07:14,817 DEBUG [main] o.s.b.f.s.DefaultListableBeanFactory [AbstractBeanFactory.java:243] Returning cached instance of singleton bean 'lifecycleProcessor'
2015-06-03 00:07:14,821 DEBUG [main] o.s.c.e.PropertySourcesPropertyResolver [PropertySourcesPropertyResolver.java:81] Searching for key 'spring.liveBeansView.mbeanDomain' in [systemProperties]
2015-06-03 00:07:14,821 DEBUG [main] o.s.c.e.PropertySourcesPropertyResolver [PropertySourcesPropertyResolver.java:81] Searching for key 'spring.liveBeansView.mbeanDomain' in [systemEnvironment]
2015-06-03 00:07:14,822 DEBUG [main] o.s.c.e.PropertySourcesPropertyResolver [PropertySourcesPropertyResolver.java:103] Could not find key 'spring.liveBeansView.mbeanDomain' in any property source. Returning [null]
2015-06-03 00:07:14,822 DEBUG [main] o.s.b.f.s.DefaultListableBeanFactory [AbstractBeanFactory.java:243] Returning cached instance of singleton bean 'person'
com.siyuan.test.slf4j.entity.Person@26d66426
2015-06-03 00:07:14,822 DEBUG [main] o.s.b.f.s.DefaultListableBeanFactory [AbstractBeanFactory.java:243] Returning cached instance of singleton bean 'person'
siyuan

log4j和JUL的重定向也类似

参考资料

http://www.slf4j.org/legacy.html