一、利用JavaMail傳送郵件案例：

1、maven專案結構：

2、先在pom.xml裡邊加入Javamail依賴，系統會根據座標自動下載mail包（前提是配置好了maven）：

3、配置email.properties屬性檔案，主要是為了不更改程式碼的前提下，該改變傳送郵件的一些基本資訊：

4、實現傳送郵件的主體類SendMailUtils，程式碼下：

package top.hzelin.util;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

 
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
 
import javax.mail.internet.MimeMultipart;



public class SendMailUtils {
    private static String from = "";
    private static String user = "";
    private static String password = "";
    /*
     * 讀取屬性檔案的內容，併為上面上個屬性賦初始值
     */
    static {
        Properties prop = new Properties();
        InputStream is 
 
= SendMailUtils.class.getClassLoader().getResourceAsStream("email.properties");
        try {
            prop.load(is);
            from = prop.getProperty("from");
            user=prop.getProperty("username");
            password=prop.getProperty("password");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static void sendMail(String to,String text,String title) {
        Properties props = new Properties();
        props.setProperty("mail.smtp.host", "smtp.163.com");//設定郵件伺服器主機名
        props.put("mail.smtp.host", "smtp.163.com");
        props.put("mail.smtp.auth", "true");//傳送伺服器需要身份驗證
        Session session = Session.getDefaultInstance(props);//設定環境資訊
        session.setDebug(true);
        MimeMessage message = new MimeMessage(session);
        Multipart multipart = null;
        BodyPart contentPart = null;
        Transport transport = null;
        try {
            message.setFrom(from);//設定發件人
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
            message.setSubject(title);
            multipart = new MimeMultipart();//設定附件
            contentPart = new MimeBodyPart();
            contentPart.setContent(text, "text/html;charset=utf-8");
            multipart.addBodyPart(contentPart);
            message.setContent(multipart);
            message.saveChanges();
            transport = session.getTransport("smtp");
            transport.connect("smtp.163.com", user, password);
            transport.sendMessage(message, message.getAllRecipients());
        } catch (MessagingException e) {
            
            e.printStackTrace();
        }finally {
            try {
                transport.close();
            } catch (MessagingException e) {
                e.printStackTrace();
            }
        }
        
        
        
    }

}

5、測試傳送郵件功能是否可用SendEmailTest：

注意：email.properties配置檔案中的密碼應該是客戶端授權碼，不是登入密碼，設定位置如下：