Question

我正在尝试通过gmails SMTP Server使用JavaMail发送电子邮件。但是这段代码。

final String username = "mygmail@gmail.com";
    final String password = "mygmailpassword";

    Properties props = new Properties();
    props.put("mail.smtp.auth", true);
    props.put("mail.smtp.starttls.enable", true);
    props.put("mail.smtp.host", "smtp.gmail.com");
    props.put("mail.smtp.port", "587");

    Session session = Session.getInstance(props,
            new javax.mail.Authenticator() {
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(username, password);
                }
            });

    try {

        Message message = new MimeMessage(session);
        message.setFrom(new InternetAddress("no-reply@gmail.com"));
        message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse("test@gmail.com"));
        message.setSubject("Testing Subject");
        message.setText("Dear Mail Crawler,"
                + "\n\n No spam to my email, please!");

        Transport.send(message);

        System.out.println("Done");

    } catch (MessagingException e) {
        throw new RuntimeException(e);
    }

返回此错误

Could not convert socket to TLS;

完整的堆栈跟踪

Exception in thread "main" java.lang.RuntimeException: 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
    at Test.main(Test.java:43)
Caused by: 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
    at com.sun.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:1907)
    at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:666)
    at javax.mail.Service.connect(Service.java:317)
    at javax.mail.Service.connect(Service.java:176)
    at javax.mail.Service.connect(Service.java:125)
    at javax.mail.Transport.send0(Transport.java:194)
    at javax.mail.Transport.send(Transport.java:124)
    at Test.main(Test.java:38)
Caused by: 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
    at com.sun.net.ssl.internal.ssl.Alerts.getSSLException(Alerts.java:174)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1649)
    at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:241)
    at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:235)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1206)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:136)
    at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Handshaker.java:593)
    at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Handshaker.java:529)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:893)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1138)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1165)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1149)
    at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:549)
    at com.sun.mail.util.SocketFetcher.startTLS(SocketFetcher.java:486)
    at com.sun.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:1902)
    ... 7 more
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:323)
    at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:217)
    at sun.security.validator.Validator.validate(Validator.java:218)
    at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:126)
    at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:209)
    at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:249)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1185)
    ... 17 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:174)
    at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:238)
    at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:318)
    ... 23 more

Answer 1

props.put("mail.smtp.ssl.trust", "smtp.gmail.com");

Answer 2

确保您的防病毒程序没有干扰，并确保在防火墙中添加排除项。

Answer 3

我禁用avast防病毒10分钟并使其正常工作。

Answer 4

当用于发送电子邮件的默认 SSL 协议设置为 TLSv1 并且 smtp 服务器不再支持此协议时，我遇到了类似的问题。诀窍是使用较新的协议：

mail.smtp.ssl.protocols=TLSv1.2

Answer 5

@carlos 的第一个答案为我效劳：

session.getProperties().put("mail.smtp.ssl.trust", "smtp.gmail.com");

我已经测试了下面的属性，并且对我来说也很完美：

session.getProperties().put("mail.smtp.starttls.enable", "true");

这两个属性单独解决了这类问题，但保证我同时使用了这两个问题。

Answer 6

经过一整天的搜索，我禁用了Avast 10分钟并禁用了Windows防火墙（重要），一切开始正常工作！

这是我的错误：

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

以下是通过在SMTP端口587（或应用程序使用的任何端口）中添加排除项来解决Avast 19.8.2393中的问题的方法：

打开Avast

点击“设置”

单击“疑难解答”，然后单击“打开旧设置”

再次单击“疑难解答”，向下滚动到“重定向设置”，然后删除您的应用使用的端口。

就我而言，我刚刚从SMTP端口中删除了587。

现在，我可以使用Avast并已打开Windows防火墙（无需为防火墙添加其他排除项）。

这是我的 application.properties 电子邮件属性：

###### I am using a Google App Password which I generated in my Gmail Security settings ###### spring.mail.host = smtp.gmail.com spring.mail.port = 587 spring.mail.protocol = smtp spring.mail.username = gmail account spring.mail.password = password spring.mail.properties.mail.smtp.auth=true spring.mail.properties.mail.smtp.starttls.enable=true spring.mail.properties.mail.smtp.connectiontimeout=5000 spring.mail.properties.mail.smtp.timeout=5000 spring.mail.properties.mail.smtp.writetimeout=5000

Answer 7

对于我来说，问题是通过删除行

解决的

prop.put("mail.smtp.starttls.enable", "true");

这可能是由于电子邮件服务器上的某些ssl配置错误引起的，我不确定。电子邮件服务器管理员从不接受它，而总是将责任归咎于托管服务提供商：）

Answer 8

如果你的上下文是android应用程序，然后确保您的Android设备时间设置为当前日期和时间。潜在的例外是 “SSL证书未经过身份验证。”

Answer 9

是的，它在本地主机上对我有用：

props.put("mail.smtp.ssl.trust", "smtp.gmail.com");

错误只在本地主机上抛出，所以你也应该在远程服务器上尝试。通常，上面提到的代码片段在没有 ssl.trust 属性

的情况下运行良好

Answer 10

尝试使用JavaMail附带的smtpsend程序，如here所述。如果以同样的方式失败，那么您的JDK配置或网络配置就会出现问题。

Answer 11

帮助我解决这个问题的原因是，在此之前我已经尝试了一切，就是将我安装的jre配置为JRE 1.8。

Eclipse中的步骤：Windows＆gt;首选项＆gt; java＆gt;已安装JRE＆gt; jre1.8.0

如果设置为jdk，请切换到jre（默认情况下应该使用最新的java版本设置）。

Answer 12

尝试将端口更改为465

mail.smtp.socketFactory.port=465
mail.smtp.port=465

Answer 13

如果应用程序不支持SMTP主机使用的 TLS版本，则也可能是这样。

例如，当您的应用程序（或使用较旧javax.mail JAR的Java程序）仅支持TLSv1.1时，尝试配置不使用回退功能的TLSv1.2的SMTP服务器。

Answer 14

在application.properties之上对我来说很棒：

spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.properties.mail.smtp.starttls.required=true
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.ssl.trust=smtp.gmail.com

Answer 15

检查JavaMail库的版本（mail.jar或javax.mail.jar）。也许您需要一个更新的。从此处下载最新版本：https://javaee.github.io/javamail/

Answer 16

这是工作解决方案兄弟。这是有保障的

1）首先打开您要发送邮件的Gmail帐户，例如“xyz@gmail.com”

2）打开https://support.google.com/accounts/answer/6010255?hl=en

下面的链接

3）点击“转到我的帐户中的”安全性较低的应用“部分。”选项

4）然后打开它

5）就是这样（：

这是我的代码

1 apple A,C,D,F  
2 pear A,D  
3 plum B,F  
4 banana K,P,Z  
5 orange B,C,D,H

Javamail无法将套接字转换为TLS GMail

16 个答案: