已使用 163 邮箱测试通过，且支持 SSL 连接。 发送邮件

示例：Jack 发送一封邮件给 Rose。

public class SendMail {

    public static void main(String[] args) {
        boolean isSSL = true;
        String host = "smtp.163.com";
        int port = 465;
        String from = "jack@163.com";
        String to = "rose@163.com";
        boolean isAuth = true;
        final String username = "jack@163.com";
        final String password = "jack";

        Properties props = new Properties();
        props.put("mail.smtp.ssl.enable", isSSL);
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.port", port);
        props.put("mail.smtp.auth", isAuth);

        Session session = Session.getDefaultInstance(props, new Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });

        try {
            Message message = new MimeMessage(session);

            message.setFrom(new InternetAddress(from));
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
            message.setSubject("主题");
            message.setText("内容");

            Transport.send(message);
        } catch (AddressException e) {
            e.printStackTrace();
        } catch (MessagingException e) {
            e.printStackTrace();
        }

        System.out.println("发送完毕！");
    }
}

收取邮件

示例：Rose 收取最近一封邮件。

import java.util.Date;
import java.util.Properties;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.NoSuchProviderException;
import javax.mail.Session;
import javax.mail.Store;

public class FetchMail {

    public static void main(String[] args) {
        String protocol = "pop3";
        boolean isSSL = true;
        String host = "pop.163.com";
        int port = 995;
        String username = "rose@163.com";
        String password = "rose";

        Properties props = new Properties();
        props.put("mail.pop3.ssl.enable", isSSL);
        props.put("mail.pop3.host", host);
        props.put("mail.pop3.port", port);

        Session session = Session.getDefaultInstance(props);

        Store store = null;
        Folder folder = null;
        try {
            store = session.getStore(protocol);
            store.connect(username, password);

            folder = store.getFolder("INBOX");
            folder.open(Folder.READ_ONLY);

            int size = folder.getMessageCount();
            Message message = folder.getMessage(size);

            String from = message.getFrom()[0].toString();
            String subject = message.getSubject();
            Date date = message.getSentDate();

            System.out.println("From: " + from);
            System.out.println("Subject: " + subject);
            System.out.println("Date: " + date);
        } catch (NoSuchProviderException e) {
            e.printStackTrace();
        } catch (MessagingException e) {
            e.printStackTrace();
        } finally {
            try {
                if (folder != null) {
                    folder.close(false);
                }
                if (store != null) {
                    store.close();
                }
            } catch (MessagingException e) {
                e.printStackTrace();
            }
        }

        System.out.println("接收完毕！");
    }
}

常用邮件协议

发送邮件：SMTP

收取邮件：POP3、IMAP

常用邮件配置项

配置项	说明
mail.xxx.ssl.enable	是否支持 SSL 连接
mail.xxx.host	邮件服务器主机名
mail.xxx.port	邮件服务器端口号
mail.xxx.auth	是否进行身份认证

说明：xxx 表示协议名称，例如：smtp、pop3 等。

默认端口号

	SMTP	POP3	IMAP
普通方式	25	110	143
SSL 方式	465	995	993

使用 Apache Commons Email 发送邮件

import org.apache.commons.mail.Email;
import org.apache.commons.mail.EmailException;
import org.apache.commons.mail.SimpleEmail;

public class SendMail {

    public static void main(String[] args) {
        boolean isSSL = true;
        String host = "smtp.163.com";
        int port = 465;
        String from = "jack@163.com";
        String to = "rose@163.com";
        String username = "jack@163.com";
        String password = "jack";

        try {
            Email email = new SimpleEmail();
            email.setSSLOnConnect(isSSL);
            email.setHostName(host);
            email.setSmtpPort(port);
            email.setAuthentication(username, password);
            email.setFrom(from);
            email.addTo(to);
            email.setSubject("主题");
            email.setMsg("内容");
            email.send();
        } catch (EmailException e) {
            e.printStackTrace();
        }

        System.out.println("发送完毕！");
    }
}

参考：http://commons.apache.org/proper/commons-email/userguide.html

完