在SpringBoot2.0及Spring 5.0 WebMvcConfigurerAdapter已被废弃，目前找到解决方案就有两种

1 直接实现WebMvcConfigurer （官方推荐）

例如：

@Configuration
public class WebMvcConfg implements WebMvcConfigurer {
    //todo
}

2 直接继承WebMvcConfigurationSupport

例如：

@Configuration
public class WebMvcConfg extends WebMvcConfigurationSupport {
        //todo
}

今天查了下官方api 
Deprecated. 
as of 5.0 WebMvcConfigurer has default methods (made possible by a Java 8 baseline) and can be implemented directly without the need for this adapter 
An implementation of WebMvcConfigurer with empty methods allowing subclasses to override only the methods they’re interested in. 
因此推荐第一种方式