Java SSL:找不到请求目标的有效证书路径

我在发送邮件时遇到以下错误

javax.mail.MessaginException：异常读取响应；嵌套异常为：javax.net.ssl.SSLHandshakeException:sun.security.validator.ValidatorException:PKIX路径生成失败：sun.security.provider.certpath.SunCertPathBuilderException:找不到请求目标的有效证书路径

试试这个

String to="mydaman7291@gmail.com";//change accordingly

//Get the session object
Properties props = new Properties();
props.put("mail.smtp.host", "smtp.gmail.com");
props.put("mail.smtp.socketFactory.port", "465");
props.put("mail.smtp.socketFactory.class",
        "javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.port", "465");

Session sess = Session.getInstance(props,
 new javax.mail.Authenticator() {
 protected PasswordAuthentication getPasswordAuthentication() {
 return new PasswordAuthentication("daman.bonnie07@gmail.com","password");//change accordingly
 }
});

//compose message
try {
 MimeMessage message = new MimeMessage(sess);
 message.setFrom(new InternetAddress("daman.bonnie07@gmail.com"));//change accordingly
 message.addRecipient(Message.RecipientType.TO,new InternetAddress(to));
 message.setSubject("Hello");
 message.setText("Testing.......");

 //send message
 Transport.send(message);

 System.out.println("message sent successfully");

} 
catch (MessagingException e) {
    out.println(e);}

---

添加属性

props.put（“mail.pop3s.ssl.trust”、“*”）并检查。不，我仍然得到相同的例外，如果你用谷歌搜索错误消息，你会发现几十（数百）次点击。您必须向Java密钥库添加适当的CA证书。看，我现在得到了这个错误，javax.mail.MessaginException:Exception reading response；嵌套异常是：javax.net.ssl.SSLException:无法识别的ssl消息，纯文本连接？请有人帮忙？
Properties props = new Properties();
    props.put("mail.smtp.host", "smtp.xyz.in");
    props.put("mail.smtp.socketFactory.port", "25");

    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.port", "25");
    props.put("mail.smtp.dsn.notify",
              "SUCCESS ORCPT=rfc822;");
    props.put("mail.smtp.dsn.ret", "FULL");