如何使用JAVA代码发送电子邮件？

Question

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

public class SendEMail
{
   public static void main(String [] args)
 {

  // Recipient's email ID needs to be mentioned.
  String to = "*********@gmail.com";

  // Sender's email ID needs to be mentioned
  String from = "********@gmail.com";

  // Assuming you are sending email from localhost
  String host = "465";

  // Get system properties
  Properties properties = System.getProperties();

  // Setup mail server
  properties.setProperty("mail.smtp.port", host);
  properties.put("mail.smtp.user", "*****");
  properties.put("mail.smtp.host", "smtp.gmail.com");
  properties.put("mail.smtp.port", "587");
  properties.put("mail.smtp.starttls.enable","true");
  properties.put("mail.smtp.debug", "true");
  properties.put("mail.smtp.auth", "true");
  properties.put("mail.smtp.socketFactory.port", "587");
  properties.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
  properties.put("mail.smtp.socketFactory.fallback", "false");
  properties.setProperty("mail.user", "*******");
  properties.setProperty("mail.password", "******");

  // Get the default Session object.
  Session session = Session.getDefaultInstance(properties);

  try{
     // Create a default MimeMessage object.
     MimeMessage message = new MimeMessage(session);

     // Set From: header field of the header.
     message.setFrom(new InternetAddress(from));

     // Set To: header field of the header.
     message.addRecipient(Message.RecipientType.TO,
                              new InternetAddress(to));

     // Set Subject: header field
     message.setSubject("This is the Subject Line!");

     // Create the message part 
     BodyPart messageBodyPart = new MimeBodyPart();

     // Fill the message
     messageBodyPart.setText("This is message body");

     // Create a multipar message
     Multipart multipart = new MimeMultipart();

     // Set text message part
     multipart.addBodyPart(messageBodyPart);

     // Part two is attachment
     messageBodyPart = new MimeBodyPart();
     String filename = "file.txt";
     DataSource source = new FileDataSource(filename);
     messageBodyPart.setDataHandler(new DataHandler(source));
     messageBodyPart.setFileName(filename);
     multipart.addBodyPart(messageBodyPart);

     // Send the complete message parts
     message.setContent(multipart );

     // Send message
     Transport.send(message);
     System.out.println("Sent message successfully....");
  }catch (MessagingException mex) {
     mex.printStackTrace();
    }
   }
  }

I am getting the following error. Error:

javax.mail.SendFailedException: Sending failed;
nested exception is:
class javax.mail.AuthenticationFailedException

After going through Suggestions from the same page.I have modified the code as shown above. But, this time im getting the authentication error. Plz help me where iam wrong this time?

Answer 1

  properties.setProperty("mail.smtp.host", host);

Here, host is not the machine where you are sending the email from.(As written in comments in code). It is the host where your e-mail server is.

For gmail - it is smtp.gmail.com on port 465.

You have to configure it according to your smtp server.

Answer 2

You need to more properties, I can see your code and see that there is some properties are missing like

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");   

You also need to set Authenticator and some other things, Please refer below Example: Send Mail using JAVA with Gmail Account

Answer 3

you can find the code here to send email using Java

http://javainfinite.com/java/send-email-using-gmail-in-java/

Answer 4

个人建议使用原始的SMTP协议发送邮件，只是为了更好地了解它的工作原理，但为了解决他的问题，请检查防火墙中的端口25是否不应该打开，启动新规则