Problem Description:
@ requestmapping always reports an error when returning to the view: unable to parse MVC view “index”

reason:
unable to parse because the pre suffix of splicing cannot be found, so it cannot jump. Forget to import template engine dependencies

Solution:
Add dependency in POM

    <dependency>
        <groupId>org.thymeleaf</groupId>
        <artifactId>thymeleaf-spring5</artifactId>
    </dependency>
    <dependency>
        <groupId>org.thymeleaf.extras</groupId>
        <artifactId>thymeleaf-extras-java8time</artifactId>
    </dependency>