java.lang.NoClassDefFoundError: org/codehaus/jackson/map/ObjectMapper

异常描述：项目中已经导入jacksonmapper 的jar ，访问项目依然报如下异常。

HTTP Status 500 -javax.servlet.ServletException: Servlet.init() for servlet tool threw exceptionroot causeorg.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jacksonMessageConverter' defined in ServletContext resource [/WEB-INF/tool-servlet.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springframework.http.converter.json.MappingJacksonHttpMessageConverter]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: org/codehaus/jackson/map/ObjectMapper

解决方法：因为项目中引用的其他依赖中也有该jar，产生冲突导致（排除法解决，spring的相关依赖就有该jar）。