如何解决Java中的spring temlateInput异常？

我正在使用 spring boot、thymleaf、spring MVC、gradlebuild 工具。我想用 thymleaf 模板附件实现 spring 邮件。当我在这个方法中调用 web 服务（restful）来发送电子邮件和这个方法时，我正在调用一个 spring 模板引擎来生成一个 thymleaf 模板来发送电子邮件附件。

为了进一步说明，我附上了一个流程结构。

休息控制器

@RequestMapping(value= "/completeBatchUpload")
public Map<String,String>completeBatchShipmentUpload() throws Exception {

Map<String, String> resp = new HashMap<>();
 String s = emailService.sendmail();

//----some code here based on result of emailService.sendmail method.----
 return resp;    
}

电子邮件服务.java

public String sendmail(){
     try {
        MimeMessage message = javaMail.createMimeMessage();

         try {
          MimeMessageHelper helper = new MimeMessageHelper(message, true);
          helper.setFrom(new InternetAddress("[email protected]"));
          helper.setTo(new InternetAddress("[email protected]"));
          helper.setSubject("subject here");                                                  helper.setText(attachmentUtile.buildContentUsingTemplate();

                } catch (Exception e) {
                    throw new MailParseException(e);
                }

                javaMail.send(message);
            }
    }

@Service
public class AttachmentUtile {

    private SpringTemplateEngine templateEngine;

    @Autowired
    public AttachmentUtile (SpringTemplateEngine templateEngine) {
        this.templateEngine = templateEngine;
    }

    public String buildContentUsingTemplate(List<Map<String, String>>     templateContent, String recipientName) {
        final Context ctx = new Context();
        ctx.setVariable("recipientName", "ritesh");
        String s = templateEngine.process("send", ctx);
        return s;

    }
}

发送.html

使用 Thymeleaf HTML 模板示例发送电子邮件

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>



<!-- use the font -->
<style>
    body {
        font-family: 'Roboto', sans-serif;
        font-size: 48px;
    }
</style>

<table align="center" border="0" cellpadding="0" cellspacing="0" width="600" style="border-collapse: collapse;">
    <tr>
        <td align="center" bgcolor="#78ab46" style="padding: 40px 0 30px 0;">
            <p>RITESH CHOUDAHRY</p>
        </td>
    </tr>
    <tr>
        <td bgcolor="#eaeaea" style="padding: 40px 30px 40px 30px;">
            <p>Dear ${recipientName},</p>
            <p>Sending Email using Spring Boot with <b>Thymeleaf template !!!</b></p>
            <p>Thanks</p>
        </td>
    </tr>

</table>

百里香叶配置文件

@Configuration
public class ThymLeafConfig {

    @Bean
    public SpringTemplateEngine springTemplateEngine() {
        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.addTemplateResolver(htmlTemplateResolver());
        return templateEngine;
    }

    @Bean
    public ITemplateResolver  htmlTemplateResolver(){ 
        SpringResourceTemplateResolver emailTemplateResolver = new SpringResourceTemplateResolver();
        emailTemplateResolver.setPrefix("/templates/");
        emailTemplateResolver.setSuffix(".html");
        emailTemplateResolver.setTemplateMode(StandardTemplateModeHandlers.HTML5.getTemplateModeName());
        emailTemplateResolver.setCharacterEncoding(StandardCharsets.UTF_8.name());
        return emailTemplateResolver;
    }

项目文件夹结构

我得到以下异常：

I have seen one link in stackoverflow Error resolving template “login” spring boot, thymeleaf, But still I am not able to solve my problem. If anybosy have have idea please share. Thanks in advance. If any query required please comment.