spring boot 调用 thymeleaf 模板失败

我遇到了这个错误，我在堆栈上搜索了与我相同的问题，我发现我不应该在调用它时放置 .html 但我遇到了同样的错误：

`Caused by: org.thymeleaf.exceptions.TemplateInputException: Error resolving template "orderConfirmationEmailTemplate", template might not exist or might not be accessible by any of the configured Template Resolver`s

我的邮件构造函数：

@Component
public class MailConstructor {

    @Autowired
    private Environment env;

    @Autowired
    private TemplateEngine templateEngine;

    public SimpleMailMessage constructNewUserEmail(User user, String password) {
        String message="\nPlease use the following credentials to log in and edit your personal information including your own password."
                + "\nUsername:"+user.getUsername()+"\nPassword:"+password;

        SimpleMailMessage email = new SimpleMailMessage();
        email.setTo(user.getEmail());
        email.setSubject("Le's Bookstore - New User");
        email.setText(message);
        email.setFrom(env.getProperty("support.email"));
        return email;
    }

    public MimeMessagePreparator constructOrderConfirmationEmail (User user, Order order, Locale locale) {
        Context context = new Context();
        context.setVariable("order", order);
        context.setVariable("user", user);
        context.setVariable("cartItemList", order.getCartItemList());
        String text = templateEngine.process("orderConfirmationEmailTemplate.html", context);

        MimeMessagePreparator messagePreparator = new MimeMessagePreparator() {
            @Override
            public void prepare(MimeMessage mimeMessage) throws Exception {
                MimeMessageHelper email = new MimeMessageHelper(mimeMessage);
                email.setTo(user.getEmail());
                email.setSubject("Order Confirmation - "+order.getId());
                email.setText(text,true);
                email.setFrom(new InternetAddress("[email protected]"));
            }
        };

        return messagePreparator;
    }

我从休息服务中调用它：

mailSender.send(mailConstructor.constructOrderConfirmationEmail(user, order, Locale.ENGLISH));

    shoppingCartService.clearShoppingCart(shoppingCart);

我将文件 .html 放在项目中的包下