spring 引导中的 Gmail Api：javax.mail.MessagingException：无法将套接字转换为 TLS

Question

我正在后端使用 spring-boot，我尝试使用 smtp 向 gmail 帐户发送电子邮件，但遇到了一些错误。

下面是我的代码 tutorial :

application.properties :

spring.mail.host=smtp.gmail.com
spring.mail.port=587
spring.mail.username=xxx@gmail.com
spring.mail.password=xxxpwd
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true

Class MailObject.java :

    package interv.Web.Notifications;

import org.hibernate.validator.constraints.Email;

import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

public class MailObject {

    @Email
    @NotNull
    @Size(min = 1, message = "Please, set an email address to send the message to it")
    private String to;
    private String subject;
    private String text;

    public String getTo() {
        return to;
    }

    public void setTo(String to) {
        this.to = to;
    }

    public String getSubject() {
        return subject;
    }

    public void setSubject(String subject) {
        this.subject = subject;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }
}

MailController.java :

    @Controller
public class MailController {

    @Autowired
    public EmailServiceImpl emailService;

    @Autowired
    public SimpleMailMessage template;

    @RequestMapping(value = "/send", method = RequestMethod.POST)
    public String createMail(@RequestBody MailObject mailObject) {


        emailService.sendSimpleMessage(mailObject.getTo(),
                mailObject.getSubject(), mailObject.getText());

        return "that was succesfull";

    }
}

EmailService.java

public interface EmailService {

    void sendSimpleMessage(String to,
                           String subject,
                           String text);
    void sendSimpleMessageUsingTemplate(String to,
                                        String subject,
                                        SimpleMailMessage template,
                                        String templateArgs);

}

EmailServiceImpl.java

@Component
public class EmailServiceImpl implements EmailService{

    @Autowired
    public JavaMailSender emailSender;

    @Override
    public void sendSimpleMessage(String to, String subject, String text) {
        SimpleMailMessage message = new SimpleMailMessage();
        message.setTo(to);
        message.setSubject(subject);
        message.setText(text);

        emailSender.send(message);
    }

    @Override
    public void sendSimpleMessageUsingTemplate(String to, String subject, SimpleMailMessage template, String templateArgs) {
        String text = String.format(template.getText(), templateArgs);
        sendSimpleMessage(to, subject, text);
    }
}

虽然运行我在控制台中没有收到任何错误，但是当我尝试发送电子邮件时出现此错误：

servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.mail.MailSendException: Mail server connection failed; nested exception is javax.mail.MessagingException: Could not convert socket to TLS;
  nested exception is:
    javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target. Failed messages: javax.mail.MessagingException: Could not convert socket to TLS;
  nested exception is:
    javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target; message exceptions (1) are:
Failed message 1: javax.mail.MessagingException: Could not convert socket to TLS;
  nested exception is:
    javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target] with root cause

sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141) ~[na:1.8.0_161]
    at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126) ~[na:1.8.0_161]
    at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280) ~[na:1.8.0_161]

我不明白为什么会出现此错误：知道吗？

Answer 1

错误清楚地表明“UnknownHost”。检查您的应用程序是否可以访问互联网并能够解析名称。

Answer 2

我认为原因是 Gmail 出于安全原因默认阻止安全性较低的应用程序访问检查这个类似的问题它的答案可能对你有帮助 Error sending email with gmail

spring 引导中的 Gmail Api：javax.mail.MessagingException：无法将套接字转换为 TLS

Gmail Api in spring boot : javax.mail.MessagingException: Could not convert socket to TLS

java

gmail

spring

jakarta-mail

spring-boot