Spring Boot 使用 Thymeleaf 作为模板发送电子邮件 - 配置不起作用

Question

我有一个基于 Spring Boot（最新 1.1.5.RELEASE）和 Thymeleaf 的工作 WebApp。
现在我想添加功能来发送电子邮件并使用 Thymeleaf 作为模板引擎。

在 pom.xml 我添加：

<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-mail</artifactId>
</dependency>

<dependency>
    <groupId>javax.mail</groupId>
    <artifactId>mail</artifactId>
    <version>1.4.7</version>
</dependency>
<dependency>
    <groupId>javax.activation</groupId>
    <artifactId>activation</artifactId>
    <version>1.1.1</version>
</dependency>

按照本教程：http://www.thymeleaf.org/doc/articles/springmail.html
我得到了这样的完整（无 XML）Java 配置：

@Configuration
public ThymeleafReplaceConfigurator {
  @Bean 
   public JavaMailSender getJavaMailSenderImpl(){
        JavaMailSenderImpl javaMailSender = new JavaMailSenderImpl();

        Properties props = new Properties();
        /* some properties here */

        javaMailSender.setJavaMailProperties(props);

    return javaMailSender;
    }

    @Bean
    public ClassLoaderTemplateResolver emailTemplateResolver(){
        ClassLoaderTemplateResolver emailTemplateResolver = new ClassLoaderTemplateResolver();
        emailTemplateResolver.setPrefix("/mails/");
        emailTemplateResolver.setSuffix(".html");
        emailTemplateResolver.setTemplateMode("HTML5");
        emailTemplateResolver.setCharacterEncoding("UTF-8");
        emailTemplateResolver.setOrder(1);

        return emailTemplateResolver;
    }

    @Bean
    public ServletContextTemplateResolver defaultWebTemplateResolver(){
        ServletContextTemplateResolver webTemplateResolver = new ServletContextTemplateResolver();
        webTemplateResolver.setPrefix("/templates/");
        webTemplateResolver.setSuffix(".html");
        webTemplateResolver.setTemplateMode("HTML5");
        webTemplateResolver.setCharacterEncoding("UTF-8");
        webTemplateResolver.setOrder(2);

        return webTemplateResolver;
    }

    @Bean
    public SpringTemplateEngine templateEngine(){
    SpringTemplateEngine templateEngine = new SpringTemplateEngine();
    templateEngine.setTemplateResolver(emailTemplateResolver());
    templateEngine.setTemplateResolver(defaultWebTemplateResolver());
    return templateEngine;
    }

    @Bean
    public ThymeleafViewResolver thymeleafViewResolver() {
        ThymeleafViewResolver thymeleafViewResolver = new ThymeleafViewResolver();

        thymeleafViewResolver.setTemplateEngine(templateEngine());
        thymeleafViewResolver.setCharacterEncoding("UTF-8");

        return thymeleafViewResolver;
    }
}

文件夹和文件树如下：

src
  main
    resources
      templates
        login.html
        error.html
      mails
        exampleMail.html

但它不起作用。应用程序正常启动，但访问页面（无需此配置也能正常工作）会导致以下异常：

请求处理失败；嵌套异常是 org.thymeleaf.exceptions.TemplateInputException：解析模板“登录”时出错，模板可能不存在或可能无法被任何已配置的模板解析器访问

我试图将不同的前缀放入 webTemplateResolver.setPrefix 但没有成功。
此外，我注意到 Thymeleaf 早期版本中报告的错误导致该错误，但看起来它已修复并且我有更新版本。

有人看到此配置中的错误吗？

Answer 1

主要问题是你配置太多了。

Spring Boot 已经配置了 TemplateEngine 和 ThymeleafViewResolver。请参阅ThymeleafAutoConfiguration。如果您look at that class，您还会注意到它会自动检测您的应用程序中可能存在的任何ITemplateResolver 实例，并将其添加到SpringTemplateEngine。

解决方案非常简单，删除除电子邮件配置和emailTemplateResolver 之外的所有内容。其他一切都将由 Spring Boot 处理。

@Configuration
public class ThymeleafEmailConfiguration {
   @Bean 
   public JavaMailSender getJavaMailSenderImpl(){
        JavaMailSenderImpl javaMailSender = new JavaMailSenderImpl();

        Properties props = new Properties();
        /* some properties here */

        javaMailSender.setJavaMailProperties(props);

        return javaMailSender;
    }

    @Bean
    public ClassLoaderTemplateResolver emailTemplateResolver(){
        ClassLoaderTemplateResolver emailTemplateResolver = new ClassLoaderTemplateResolver();
        emailTemplateResolver.setPrefix("/mails/");
        emailTemplateResolver.setSuffix(".html");
        emailTemplateResolver.setTemplateMode("HTML5");
        emailTemplateResolver.setCharacterEncoding("UTF-8");
        emailTemplateResolver.setOrder(1);

        return emailTemplateResolver;
    }
}