java - 在 Spring Boot 中使用 JavaMailSender

Question

我使用 Spring Initializer、嵌入式 Tomcat、Thymeleaf 模板引擎生成了一个 Spring Boot Web 应用程序，并将其打包为可执行 JAR 文件。

使用的技术:

Spring Boot 1.4.2.RELEASE、Spring 4.3.4.RELEASE、Thymeleaf 2.1.5.RELEASE、Tomcat Embed 8.5.6、Maven 3、Java 8

我创建了此服务来发送电子邮件

@Service
public class MailClient {

    protected static final Logger looger = LoggerFactory.getLogger(MailClient.class);

    @Autowired
    private JavaMailSender mailSender;

    private MailContentBuilder mailContentBuilder;

    @Autowired
    public MailClient(JavaMailSender mailSender, MailContentBuilder mailContentBuilder) {
        this.mailSender = mailSender;
        this.mailContentBuilder = mailContentBuilder;
    }

    //TODO: in a properties
    public void prepareAndSend(String recipient, String message) {
        MimeMessagePreparator messagePreparator = mimeMessage -> {
            MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage);
            messageHelper.setFrom("nunito@calzada.com");
            messageHelper.setTo(recipient);
            messageHelper.setSubject("Sample mail subject");
            String content = mailContentBuilder.build(message);
            messageHelper.setText(content, true);
        };
        try {
            if (looger.isDebugEnabled()) {
                looger.debug("sending email to " + recipient);
            }
            mailSender.send(messagePreparator);
        } catch (MailException e) {
            looger.error(e.getMessage());
        }
    }
}

但是在初始化 SpringBootApplication 时出现此错误

***************************
APPLICATION FAILED TO START
***************************

Description:

Binding to target org.springframework.boot.autoconfigure.mail.MailProperties@1e94ed11 failed:

    Property: spring.mail.defaultEncoding
    Value: UTF-8 
    Reason: Failed to convert property value of type 'java.lang.String' to required type 'java.nio.charset.Charset' for property 'defaultEncoding'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [java.lang.String] to type [java.nio.charset.Charset]


Action:

Update your application's configuration

这是我的 application.properties

spring.mail.host=localhost
spring.mail.port=25 
spring.mail.username= 
spring.mail.password= 
spring.mail.protocol=smtp
spring.mail.defaultEncoding=UTF-8 

Answer 1

注释不能与属性位于同一行。每个注释必须在自己的行中，以“#”开头错误信息显示

Value: 25 # SMTP server port

所以该值为字符串'25 # SMTP服务器端口'，无法转换为整数。

将注释移到其自己的行中，位于属性上方:

# SMTP server port
spring.mail.port=25