sl4j的一个版本冲突

在tomcat启动时报错：
严重: Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in file [D:\lvlf\workspace\ssh\target\ssh\WEB-INF\classes\applicationContext.xml]: Invocation of init method failed; nested exception is java.lang.IllegalAccessError: tried to access field org.slf4j.impl.StaticLoggerBinder.SINGLETON from class org.slf4j.LoggerFactory
...
Caused by: java.lang.IllegalAccessError: tried to access field org.slf4j.impl.StaticLoggerBinder.SINGLETON from class org.slf4j.LoggerFactory
...

原因分析:
jar文件版本冲突.从网上查询得知类: org.slf4j.impl.StaticLoggerBinder在slf4j-api 中是类的公有静态变量,而在slf4j-log4j12（slf4j-nop.jar, slf4j-simple.jar, slf4j-log4j12.jar, slf4j-jdk14.jar or logback-classic.jar其中之一）中确是私有变量
解决办法：
在类路径先将slf4j-api.jar 删除，再导入同版本的slf4j-api-1.5.6.jar 和slf4j-log4j12-1.5.6.jar