spring-boot-starter-thymeleaf dependency cannot be introduced

The instructional video let us introduce this dependency

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

Then it kept being marked red, and then I couldn’t find a solution through various Baidus.
I thought about creating a new module to try, and then I found New World

In this way, the introduction of the dependency is directly completed in the project

summary of the issue:

1. I personally think this is a version issue. The instructional video uses 1.5, but now it is 2.3

2. If the jar package download fails, go to the jar package download directory of maven found, delete it, and download it again. The default
directory is the user under the c drive.m2\repository\org\springframework

3. Link: thymeleaf version issue .

4. The controller layer
must use Controller annotations; not RestController because it is a rest interface (json format) and cannot parse html

5. HTML files should be placed in the resource\templates folder

It's another day to step on the pit~

Link: The pom.xml file always reports errors, always prompting Dependency'xxxx' not found . Pro-test is valid