This may be the result of an unspecified view, due to default view name generation 报错解决

启动SpringBoot项目报以下错误：

javax.servlet.ServletException: Circular view path [index]: would
dispatch back to the current handler URL [/index] again. Check your View Resolver setup! (Hint: This may be the result of an unspecified view, due to default view name generation.)

可能原因：

1. pom文件里缺少thymeleaf依赖

   <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
   </dependency>

2. @controller上面缺少 @ResonseBody