使用 JavaMail 實現郵件發送與收取

已使用 163 郵箱測試經過，且支持 SSL 鏈接。

發送郵件

示例：Jack 發送一封郵件給 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("主題");
            message.setText("內容");

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

        System.out.println("發送完畢！");
    }
}

收取郵件

示例：Rose 收取最近一封郵件。

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("接收完畢！");
    }
}

經常使用郵件協議

發送郵件：SMTP

收取郵件：POP三、IMAP

經常使用郵件配置項

配置項	說明
mail.xxx.ssl.enable	是否支持 SSL 鏈接
mail.xxx.host	郵件服務器主機名
mail.xxx.port	郵件服務器端口號
mail.xxx.auth	是否進行身份認證

說明：xxx 表示協議名稱，例如：smtp、pop3 等。

默認端口號

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

使用 Apache Commons Email 發送郵件

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("主題");
            email.setMsg("內容");
            email.send();
        } catch (EmailException e) {
            e.printStackTrace();
        }

        System.out.println("發送完畢！");
    }
}

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

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