因為swagger版本與knife4j不兼容
<dependency>
<groupId>com.github.xiaoymin</groupId>
<artifactId>knife4j-spring-boot-starter</artifactId>
<version>3.0.3</version>
</dependency>
3.0.3版本太高可以降成2.0.4或2.0.9都行
<dependency>
<groupId>com.github.xiaoymin</groupId>
<artifactId>knife4j-spring-boot-starter</artifactId>
<version>2.0.4</version>
</dependency>