使用JavaMail SMTP协议发送邮件

最近需要实现通过发送邮件让用户找回密码的功能，自己用Socket写了SMTP协议的邮件发送程序，但是很多邮件服务器的anti-spam需要验证发送邮箱的合法性，所以只得放弃，后来发现用javamail包可以很方便的实现。示例程序使用gmail的邮件服务器来发送邮件。关于SMTP端口等配置见下面链接：

https://support.google.com/mail/bin/answer.py?hl=en&answer=13287

注：下面程序需导入javaee-api-6.0.jar 跟 mail.jar

1.使用TLS发送邮件

import java.util.Properties;
 
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
 
public class SendMailTLS {
 
	public static void main(String[] args) {
 
		final String username = "someoe@gmail.com";
		final String password = "password";
 
		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("someone@gmail.com"));
			message.setRecipients(Message.RecipientType.TO,
				InternetAddress.parse("someone@yourISP.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);
		}
	}
}

2.使用SSL发送邮件

import java.util.Properties;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
 
public class SendMailSSL {
	public static void main(String[] args) {
		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 session = Session.getDefaultInstance(props,
			new javax.mail.Authenticator() {
				protected PasswordAuthentication getPasswordAuthentication() {
					return new PasswordAuthentication("username","password");
				}
			});
 
		try {
 
			Message message = new MimeMessage(session);
			message.setFrom(new InternetAddress("from@no-spam.com"));
			message.setRecipients(Message.RecipientType.TO,
					InternetAddress.parse("to@no-spam.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);
		}
	}
}