使用JavaMail API发送邮件

发送邮件是很常用的功能，注册验证，找回密码，到货通知，欠费提醒等，都可以通过邮件来提醒。

Java中发送邮件需要使用javax.mail.jar包，读者可以上网搜索或去官方下载，下载地址为：

下面贴上发送邮件的核心代码。

 1 // Get system properties

 2         Properties properties = System.getProperties();

 3 

 4         // Setup mail server

 5         properties.setProperty("mail.smtp.host", host);

 6         properties.setProperty("mail.smtp.port", port);

 7         properties.put("mail.smtp.auth", "true");

 8 

 9         // create email authenticator.

10         Authenticator authenticator = new Authenticator() {

11             protected PasswordAuthentication getPasswordAuthentication() {

12                 return new PasswordAuthentication(username, password);

13             }

14         };

15 

16         // Get the default Session object.

17         Session session = Session.getDefaultInstance(properties, authenticator);

18 

19         try {

20             // Create a default MimeMessage object.

21             MimeMessage message = new MimeMessage(session);

22 

23             // Set From: header field of the header.

24             message.setFrom(new InternetAddress(from));

25 

26             // Set To: header field of the header.

27             for (String to : toList) {

28                 message.addRecipient(Message.RecipientType.TO,

29                         new InternetAddress(to));

30             }

31 

32             // Set Subject: header field

33             message.setSubject("这是邮件标题", "utf-8");58 

59             // Send the complete message parts

60             message.setContent("这里是邮件内容", "text/html;charset=utf-8");

61 

62             // Send message

63             Transport.send(message);

64             System.out.println("Sent message successfully....");

65         } catch (MessagingException mex) {

66             mex.printStackTrace();67         }

 

我自己定义了一个类EmailSender，这个类提供了邮件群发功能，以及在邮件中发送附件。用户继承这个类，重载getSubject，getContent和getAttachments这三个方法便可以发送邮件。

类定义如下：

package com.iot.common.email;



import java.io.File;



import javax.activation.DataHandler;



import javax.activation.DataSource;



import javax.activation.FileDataSource;



import javax.mail.Multipart;



import javax.mail.internet.MimeMultipart;



import javax.mail.internet.MimeBodyPart;



import javax.mail.BodyPart;



import javax.mail.PasswordAuthentication;



import javax.mail.Authenticator;



import java.util.ArrayList;



import javax.mail.MessagingException;



import javax.mail.Transport;



import javax.mail.Message;



import javax.mail.internet.InternetAddress;



import javax.mail.internet.MimeMessage;



import javax.mail.Session;



import java.util.Properties;



import java.util.List;



/**

 * 邮件发送类，用来发送邮件给用户.<br />

 * 

 * @author Sam

 * 

 */

public abstract class EmailSender extends Authenticator {



    private String host;

    private String port;

    private String username;

    private String password;

    private String from;



    public EmailSender() {

        this.host = PropertiesUtil.getProperty(Constant.EMAIL_HOST);

        this.port = PropertiesUtil.getProperty(Constant.EMAIL_HOST_PORT);

        this.username = PropertiesUtil.getProperty(Constant.EMAIL_USER_NAME);

        this.password = PropertiesUtil.getProperty(Constant.EMAIL_PASSWORD);

        this.from = PropertiesUtil.getProperty(Constant.EMAIL_SENDER);

    }



    /**

     * EmailSender构造函数，需要用户提供host,port,username,password,from等信息。<br />

     * 

     * @param host

     *            ,smtp服务器地址

     * @param port

     *            ,smtp服务器端口

     * @param username

     *            ,邮箱用户名

     * @param password

     *            ,邮箱密码

     * @param from

     *            ,邮箱发送人

     */

    public EmailSender(String host, String port, String username,

            String password, String from) {

        this.host = host;

        this.port = port;

        this.username = username;

        this.password = password;

        this.from = from;

    }



    /**

     * 发送邮件到指定用户

     * 

     * @param to

     *            , 邮件发送对象

     * @return ture 发送成功, false发送失败

     */

    public Boolean send(String to) {



        List<String> toList = new ArrayList<>();

        toList.add(to);



        return send(toList);

    }



    /**

     * 群发邮件

     * 

     * @param toList

     *            ,需要接受邮件的用户

     * @return ture 发送成功, false发送失败

     */

    public Boolean send(List<String> toList) {



        // Get system properties

        Properties properties = System.getProperties();



        // Setup mail server

        properties.setProperty("mail.smtp.host", host);

        properties.setProperty("mail.smtp.port", port);

        properties.put("mail.smtp.auth", "true");



        // create email authenticator.

        Authenticator authenticator = new Authenticator() {

            protected PasswordAuthentication getPasswordAuthentication() {

                return new PasswordAuthentication(username, password);

            }

        };



        // Get the default Session object.

        Session session = Session.getDefaultInstance(properties, authenticator);



        try {

            // Create a default MimeMessage object.

            MimeMessage message = new MimeMessage(session);



            // Set From: header field of the header.

            message.setFrom(new InternetAddress(from));



            // Set To: header field of the header.

            for (String to : toList) {

                message.addRecipient(Message.RecipientType.TO,

                        new InternetAddress(to));

            }



            // Set Subject: header field

            message.setSubject(getSubject(), "utf-8");



            // Create the message part

            BodyPart messageBodyPart = new MimeBodyPart();



            // Fill the message

            messageBodyPart.setContent(getContent(), "text/html;charset=utf-8");



            // Create a multipar message

            Multipart multipart = new MimeMultipart();



            // Set text message part

            multipart.addBodyPart(messageBodyPart);



            // add attachment

            List<File> attchments = getAttachments();

            if (attchments != null && attchments.size() > 0) {

                for (File attachment : attchments) {

                    messageBodyPart = new MimeBodyPart();

                    DataSource source = new FileDataSource(attachment);

                    messageBodyPart.setDataHandler(new DataHandler(source));

                    messageBodyPart.setFileName(attachment.getName());

                    multipart.addBodyPart(messageBodyPart);

                }

            }



            // Send the complete message parts

            message.setContent(multipart);



            // Send message

            Transport.send(message);

            System.out.println("Sent message successfully....");

        } catch (MessagingException mex) {

            mex.printStackTrace();



            return false;

        }



        return true;

    }



    /**

     * 获取邮件主题，支持html格式。

     * 

     * @return

     */

    protected abstract String getSubject();



    /**

     * 获取邮件内容，支持html格式。

     * 

     * @return

     */

    protected abstract String getContent();



    /**

     * 获取附件列表，若不需要发送附件，请返回null或长度为0的List<File>列表.<br />

     * 

     * @return

     */

    protected abstract List<File> getAttachments();



}

 

与邮件发送服务器相关信息存储在properties.xml文件中，文件结构如下：

 

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">

<properties>

    <comment>邮件系统配置文件</comment>



    <entry key="EMAIL_HOST">smtp.126.com</entry>



    <entry key="EMAIL_HOST_PORT">25</entry>



    <entry key="EMAIL_USER_NAME"><username>@126.com</entry>



    <entry key="EMAIL_PASSWORD"><password></entry>



    <entry key="EMAIL_SENDER"><username>@126.com</entry>

</properties>

 

 

PropertiesUtil类用于读取properties.xml文件中的属性，代码如下：

/**

 * 

 */

package com.iot.common.email;



import java.io.IOException;

import java.io.InputStream;

import java.util.InvalidPropertiesFormatException;

import java.util.Properties;



/**

 * @author Sam <br />

 * 读取properties信息 <br />

 * 

 */

public class PropertiesUtil {



    /**

     * Get property by name

     * 

     * @param name

     * @return

     */

    public static String getProperty(String name) {

        return properties.getProperty(name);

    }



    private static Properties properties;



    /****

     * Initialize properties

     */

    static {

        String filePath = "properties.xml";

        InputStream stream = PropertiesUtil.class.getClassLoader()

                .getResourceAsStream(filePath);



        properties = new Properties();



        try {

            properties.loadFromXML(stream);

        } catch (InvalidPropertiesFormatException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        } finally {

            try {

                stream.close();

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

    }

}

 

静态常量类Contanst代码如下：

package com.iot.common.email;



/**

 * 

 * @author Lynn

 * 

 *         Store all constant field

 * 

 */

public class Constant {



    /* email sending information */

    public static final String EMAIL_HOST = "EMAIL_HOST";

    public static final String EMAIL_HOST_PORT = "EMAIL_HOST_PORT";

    public static final String EMAIL_USER_NAME = "EMAIL_USER_NAME";

    public static final String EMAIL_PASSWORD = "EMAIL_PASSWORD";

    public static final String EMAIL_SENDER = "EMAIL_SENDER";



}

 

测试代码如下：

 1 package com.iot.common.email;

 2 

 3 import java.io.File;

 4 

 5 import java.util.ArrayList;

 6 

 7 import java.util.List;

 8 

 9 public class EmailTest {

10 

11     /**

12      * @param args

13      */

14     public static void main(String[] args) {

15         // TODO Auto-generated method stub

16 

17         EmailSender sender = new EmailSender() {

18 

19             @Override

20             protected String getSubject() {

21                 // TODO Auto-generated method stub

22                 return "测试邮件，请不要回复";

23             }

24 

25             @Override

26             protected String getContent() {

27                 // TODO Auto-generated method stub

28                 return "<h1>尊敬的用户:</h1><br /><p>这是一封测试邮件，请不要恢复改邮件!</p>";

29             }

30 

31             @Override

32             protected List<File> getAttachments() {

33                 // TODO Auto-generated method stub

34                 

35                 List<File> files=new ArrayList<>();

36                 files.add(new File("d:/district.txt"));

37                 files.add(new File("d:/test2.jar"));

38                 

39                 return files;

40             }

41         };

42 

43         List<String> to = new ArrayList<>();

44         to.add("[email protected]");

45         to.add("[email protected]");

46         to.add("[email protected]");

47 

48         sender.send(to);

49 

50     }

51 

52 }