Java Mail发送简单邮件，完整代码

依赖javax.mail.jar,地址：https://java.net/projects/javamail/pages/Home

完整示例代码如下：

 package com.jadic.utils;

 import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
 import java.util.Properties;
 import java.util.regex.Pattern;

 import javax.mail.Authenticator;
 import javax.mail.Message;
 import javax.mail.MessagingException;
 import javax.mail.PasswordAuthentication;
 import javax.mail.Session;
 import javax.mail.Transport;
 import javax.mail.internet.AddressException;
 import javax.mail.internet.InternetAddress;
 import javax.mail.internet.MimeBodyPart;
 import javax.mail.internet.MimeMessage;
 import javax.mail.internet.MimeMultipart;
 import javax.mail.internet.MimeUtility;

 /**
  * 简易邮件发送<br>
  * 需提供邮件服务提供商的smtp地址、邮箱账号、密码收件人邮箱<br><br>
  * 使用方式:<br>
  * 1.实例化JMail对象，适合多次利用相同账号信息发送到相同收件人<br>
  * &nbsp;&nbsp; JMail jMail = new JMail(...);<br>
  * &nbsp;&nbsp; jMail.sendMail(subject, content);<br>
  * 2.直接调用JMail静态方法发送，需每次都将smtp、账号、收件人、内容提供<br>
  * &nbsp;&nbsp; JMail.sendMail(smtp, fromUserAddress, fromUserPass,recipients,subject,content);
  * @author Jadic
  * @created 2014-5-13
  */
 public class JMail {

     private String smtpHost;// smtp服务器地址
     private String userName;// 发送方账号
     private String userPass;// 发送方密码
     private List<String> recipientList;// 收件人列表

     private Message msg;
     private boolean isMailConfigInited;

     private final static String VALID_EMAIL_REGEX = "^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,6}$";
     private final static Pattern VALID_EMAIL_PATTERN = Pattern.compile(VALID_EMAIL_REGEX, Pattern.CASE_INSENSITIVE);

     private final static String SEND_MAIL_OK = "OK";
     private final static String SEND_MAIL_NO_RECIPIENTS = "Fail:no valid recipient set";

     private JMail(String smtp, String fromUserAddress, String fromUserPass) {
         this.smtpHost = smtp;
         this.userName = fromUserAddress;
         this.userPass = fromUserPass;

         recipientList = new ArrayList<String>();
         isMailConfigInited = false;
     }

     /**
      * @param smtp smtp服务地址
      * @param fromUserAddress  发件人邮箱账号
      * @param fromUserPass 发件人邮箱密码
      * @param recipient 收件人地址(列表),支持多个收件人以";"分割
      */
     public JMail(String smtp, String fromUserAddress, String fromUserPass, String recipient) {
         this(smtp, fromUserAddress, fromUserPass);
         String[] recs = recipient.split(";");
         for (String rec : recs) {
             if (isValidEmail(rec)) {
                 this.recipientList.add(rec);
             }
         }
     }

     /**
      * @param smtp smtp服务地址
      * @param fromUserAddress 发件人邮箱账号
      * @param fromUserPass 发件人邮箱密码
      * @param recipients  收件人地址列表
      */
     public JMail(String smtp, String fromUserAddress, String fromUserPass, String... recipients) {
         this(smtp, fromUserAddress, fromUserPass);
         for (String recipient : recipients) {
             if (isValidEmail(recipient)) {
                 this.recipientList.add(recipient);
             }
         }
     }

     /**
      * @param smtp smtp服务地址
      * @param fromUserAddress 发件人邮箱账号
      * @param fromUserPass 发件人邮箱密码
      * @param recipientList 收件人地址列表
      */
     public JMail(String smtp, String fromUserAddress, String fromUserPass, List<String> recipientList) {
         this(smtp, fromUserAddress, fromUserPass);
         for (String recipient : recipientList) {
             if (isValidEmail(recipient)) {
                 this.recipientList.add(recipient);
             }
         }
     }

     /**
      * 发送邮件,主题默认"default"
      * @param content  发送内容
      * @return "ok" 成功发送，否则返回失败提示
      */
     public String sendMail(String content) {
         return sendMail("default", content);
     }

     /**
      * @param subject    邮件主题
      * @param content    邮件内容
      * @return "ok" 成功发送，否则返回失败提示
      */
     public String sendMail(String subject, String content) {
         if (this.recipientList.size() <= 0) {
             return SEND_MAIL_NO_RECIPIENTS;
         }

         if (!isMailConfigInited) {
             try {
                 initMailConfig();
             } catch (AddressException e) {
                 return "fail: address err[" + e.getMessage().trim() + "]";
             } catch (MessagingException e) {
                 return "fail: MessagingErr[" + e.getMessage().trim() + "]";
             }
         }
         try {
             msg.setSentDate(new Date());
         } catch (MessagingException e) {
             e.printStackTrace();
         }
         try {
             msg.setSubject(MimeUtility.encodeText(subject, "gbk", "B"));

             MimeMultipart mmp = new MimeMultipart();
             MimeBodyPart mbp = new MimeBodyPart();
             mbp.setContent(content, "text/plain;charset=gbk");
             mmp.addBodyPart(mbp);
             msg.setContent(mmp);
             Transport.send(msg);
         } catch (UnsupportedEncodingException e) {
             return "fail: unsupported encoding[" + e.getMessage().trim() + "]";
         } catch (MessagingException e) {
             return "fail: MessagingErr[" + e.getMessage().trim() + "]";
         }

         return SEND_MAIL_OK;
     }

     private void initMailConfig() throws AddressException, MessagingException {
         Properties props = new Properties();
         // 发送服务器需要身份验证
         props.setProperty("mail.smtp.auth", "true");
         // 设置邮件服务器主机名
         props.setProperty("mail.host", smtpHost);
         // 发送邮件协议名称
         props.setProperty("mail.transport.protocol", "smtp");

         Session session = Session.getInstance(props, new Authenticator() {
             @Override
             protected PasswordAuthentication getPasswordAuthentication() {
                 return new PasswordAuthentication(userName, userPass);
             }
         });
         msg = new MimeMessage(session);
         msg.setFrom(new InternetAddress(userName));
         msg.addRecipients(Message.RecipientType.TO, getRecipients());
         isMailConfigInited = true;
     }

     /**
      *
      * @param smtp    smtp地址
      * @param fromUserAddress 发件人账号
      * @param fromUserPass    发件人账号密码
      * @param recipients 收件人(列表),多个收件人以";"分割
      * @param subject 邮件主题
      * @param content 邮件内容
      * @return "ok" 成功发送，否则返回失败提示
      */
     public static String sendMail(String smtp, String fromUserAddress, String fromUserPass, String recipients, String subject,
             String content) {
         final String userName = fromUserAddress;
         final String userPass = fromUserPass;
         Properties props = new Properties();
         // 发送服务器需要身份验证
         props.setProperty("mail.smtp.auth", "true");
         // 设置邮件服务器主机名
         props.setProperty("mail.host", smtp);
         // 发送邮件协议名称
         props.setProperty("mail.transport.protocol", "smtp");

         Session session = Session.getInstance(props, new Authenticator() {
             @Override
             protected PasswordAuthentication getPasswordAuthentication() {
                 return new PasswordAuthentication(userName, userPass);
             }
         });
         Message msg = new MimeMessage(session);
         try {
             msg.setFrom(new InternetAddress(userName));
             String[] recipientAry = recipients.split(";");
             InternetAddress[] recipientsAddress = new InternetAddress[recipientAry.length];
             for (int i = 0; i < recipientAry.length; i++) {
                 if (isValidEmail(recipientAry[i])) {
                     recipientsAddress[i] = new InternetAddress(recipientAry[i]);
                 }
             }
             msg.addRecipients(Message.RecipientType.TO, recipientsAddress);
             msg.setSentDate(new Date());
             msg.setSubject(MimeUtility.encodeText(subject, "gbk", "B"));

             MimeMultipart mmp = new MimeMultipart();
             MimeBodyPart mbp = new MimeBodyPart();
             mbp.setContent(content, "text/plain;charset=gbk");
             mmp.addBodyPart(mbp);
             msg.setContent(mmp);
             Transport.send(msg);
         } catch (UnsupportedEncodingException e) {
             return "fail: unsupported encoding[" + e.getMessage().trim() + "]";
         } catch (MessagingException e) {
             return "fail: MessagingErr[" + e.getMessage().trim() + "]";
         }

         return SEND_MAIL_OK;
     }

     private InternetAddress[] getRecipients() throws AddressException {
         if (recipientList.size() > 0) {
             InternetAddress[] recipients = new InternetAddress[recipientList.size()];
             for (int i = 0; i < recipients.length; i++) {
                 recipients[i] = new InternetAddress(this.recipientList.get(i));
             }
             return recipients;
         }
         return new InternetAddress[0];
     }

     private static boolean isValidEmail(String email) {
         return email != null && VALID_EMAIL_PATTERN.matcher(email).find();
     }
 }