Spring Boot 启动出现 requestMappingHandlerAdapter 错误

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerAdapter' defined in class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter]: Factory method 'requestMappingHandlerAdapter' threw exception; nested exception is java.lang.AbstractMethodError:

因为在pom.xml文件中写了2个启动类，只需要写一个就可以了

    org.springframework
    spring-webmvc
    4.0.0.RELEASE

      org.springframework.boot
      spring-boot-starter-web