在 application.properties 文件中定义设置

spring.thymeleaf.templateResolverOrder=1 

现在在创建 ITemplateResolver 的自定义 Bean 中，将 order 以及前缀和后缀设置为 0.这样spring boot会同时监听两个地方

Now in your custom Bean which creates ITemplateResolver set order to 0 along with prefix and suffix. This way spring boot will listen to both places

将 order 设置为 0 很重要

Setting order to 0 is important

bean 创建的一个例子可以是

An example of bean creation can be

@Bean
public ClassLoaderTemplateResolver emailTemplateResolver() {
    ClassLoaderTemplateResolver emailTemplateResolver = new ClassLoaderTemplateResolver();
    emailTemplateResolver.setPrefix("mails/");
    emailTemplateResolver.setSuffix(".html");
    emailTemplateResolver.setTemplateMode(TemplateMode.HTML);
    emailTemplateResolver.setCharacterEncoding("UTF-8");
    emailTemplateResolver.setOrder(0);
    emailTemplateResolver.setCheckExistence(true);

    return emailTemplateResolver;
}

我的例子