java傳送郵件一般使用在註冊賬號時、或其他通知資訊時，網站會使用郵件定時傳送、或觸發傳送郵件通知使用者；

1、我是用的是maven開發，所以需要在pom檔案中定義jar包：

<dependency>
        <groupId>javax.mail</groupId>
        <artifactId>mail</artifactId>
        <version>1.5.0-b01</version>
        </dependency>
</dependencies>

2、需要配置properties檔案放置郵箱的smtp伺服器地址和埠，以及你要使用的傳送的郵箱；

mail.smtp.host=smtp.163.com
mail.smtp.port=25
[email protected]
password=password

	public static void send_email() throws Exception{
		//你想要傳送的郵箱，可以動態載入
	        String to = "[email protected]";
	        String subject = "java郵件";//郵件主題
	        String content = "這是你的java郵件";//郵件內容
	        Properties properties = new Properties();
	        InputStream resourceAsStream = null;
	        try {
	            //此處EmployeeAction為你的當前類
	            resourceAsStream = EmployeeAction.class.getClassLoader().getResourceAsStream("/mail.properties");
//	            resourceAsStream = Object.class.getResourceAsStream("/mail.properties");
	            properties.load(resourceAsStream);
	        } finally{
	            if (resourceAsStream!=null) {
	                resourceAsStream.close();
	            }
	        }
	        System.err.println("properties:"+properties);
	        properties.put("mail.smtp.host", properties.get("mail.smtp.host"));
	        properties.put("mail.smtp.port", properties.get("mail.smtp.port"));
	        properties.put("mail.smtp.auth", "true");
	        Authenticator authenticator = new EmailAuthenticator(properties.get("userName").toString(), properties.get("password").toString());
	        javax.mail.Session sendMailSession = javax.mail.Session.getDefaultInstance(properties, authenticator);
	        MimeMessage mailMessage = new MimeMessage(sendMailSession);
	        mailMessage.setFrom(new InternetAddress(properties.get("userName").toString()));
	        // Message.RecipientType.TO屬性表示接收者的型別為TO
	        mailMessage.setRecipient(Message.RecipientType.TO, new InternetAddress(to));
	        mailMessage.setSubject(subject, "UTF-8");
	        mailMessage.setSentDate(new Date());
	        // MiniMultipart類是一個容器類，包含MimeBodyPart型別的物件
	        Multipart mainPart = new MimeMultipart();
	        // 建立一個包含HTML內容的MimeBodyPart
	        BodyPart html = new MimeBodyPart();
	        html.setContent(content.trim(), "text/html; charset=utf-8");
	        mainPart.addBodyPart(html);
	        mailMessage.setContent(mainPart);
	        Transport.send(mailMessage);
	}