springboot___addViewController配置不生效的问题及原因

问题：

1）前提

springboot项目通过实现WebMvcConfigurer并重写addViewControllers方法添加视图控制器：

registry.addViewController("/admin/index.html").setViewName("admin/index");
registry.addViewController("/student/index-stu.html").setViewName("student/index-stu");

登录判断密码正确后重定向首页：

2）测试报错

用户成功登录添加到session中，但是页面跳转失败：

报错内容：
There was an unexpected error (type=Bad Request, status=400).
Failed to convert value of type 'java.lang.String' to required type 'java.lang.Integer'; nested exception is java.lang.NumberFormatException: For input string: "index.html"
org.springframework.web.method.annotation.MethodArgumentTypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Integer'; nested exception is java.lang.NumberFormatException: For input string: "index.html"

但是自己在controller里写一个请求映射就可以访问，这个是为什么呢？

    @RequestMapping("/admin/index.html")
    public String toAdminIndex(){
        return "admin/index";
    }

    @RequestMapping("/student/index-stu.html")
    public String toStudentIndex(){
        return "student/index-stu";
    }

原因

thymeleaf的版本和springboot版本有冲突

我的pom.xml：

        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.3</version>

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

把springboot版本换成2.2.5.RELEASE应该能行

参考链接： https://blog.csdn.net/weixin_40118894/article/details/104567518 https://blog.csdn.net/weixin_43849277/article/details/107867736