发送邮件的工具类

实现java发送邮件的过程大体有以下几步：

1. 准备一个properties文件，该文件中存放SMTP服务器地址等参数。
2. 利用properties创建一个Session对象
3. 利用Session创建Message对象，然后设置邮件主题和正文
4. 利用Transport对象发送邮件

需要的jar有2个：activation.jar和mail.jar

下面是实现：

/**
     * 发送邮件的方法
     * 
     * @param serverAddress 服务器地址
     * @param user 服务器用户名
     * @param pwd 服务器密码
     * @param from 发送人
     * @param subject 标题
     * @param emailReceiver 接收人
     * @param htmlContents 发送内容
     * @param ucode 编码格式 text/html;charset=utf-8
     */
    public static void send(String serverAddress, String user, String pwd, String from, String subject, String[] emailReceiver, String htmlContents, String ucode,List<String> fileName, String fileNames) {
        if (null == fileName) {
            fileName = new ArrayList<String>();
        }
        
        try {
            Properties props = System.getProperties();
            props.put("mail.smtp.host", serverAddress);
            props.put("mail.smtp.auth", "true");
            
            Session session = Session.getDefaultInstance(props, null);
            
            Message msg = new MimeMessage(session);
            msg.setFrom(new InternetAddress(from));
            msg.setSentDate(new Date());
            msg.setSubject(subject);
            if (ucode.indexOf("GBK") != -1) {
                msg.setFrom(new InternetAddress(new String(from.getBytes("GBK"), "UTF-8")));
            }
            
            InternetAddress[] address = new InternetAddress[emailReceiver.length];
            for (int i = 0; i < address.length; i++) {
                address[i] = new InternetAddress(emailReceiver[i]);
            }
            msg.setRecipients(Message.RecipientType.TO, address);
            
            Multipart mp = new MimeMultipart();// 后面的BodyPart将加入到此处创建的Multipart中
            BodyPart bp = new MimeBodyPart();// 设置内容
            bp.setContent(htmlContents, ucode);
            mp.addBodyPart(bp);
            addFileAffix(mp, fileName, fileNames);//保存附件
            msg.setContent(mp);// Multipart加入到信件
            
            msg.saveChanges();
            
            // 发送信件
            Transport trans = session.getTransport("smtp");
            trans.connect(serverAddress, user, pwd);
            trans.sendMessage(msg, msg.getAllRecipients());
            trans.close();
        } catch (AddressException e) {
            throw new SysException("Email地址错误", e);
        } catch (UnsupportedEncodingException e) {
            throw new SysException("Email编码格式错误", e);
        } catch (NoSuchProviderException e) {
            throw new SysException("Email服务器连接错误", e);
        } catch (MessagingException e) {
            throw new SysException("Email服务器连接错误", e);
        } catch (Exception e) {
            throw new SysException(e.getMessage(), e);
        }
    }
    
    /**
     * 发送附件
     * @param mp 邮件信息
     * @param fileName 附件全路径（包括文件名称）
     * @return
     */
    public static void addFileAffix(Multipart mp, List<String> list,String fileNames) {
        if (CollectionUtils.isEmpty(list)) {
            return;
        }
        
        try{
            String[] arr = fileNames.split(";");
            for (String fileName : list) {
                if(StringUtils.isEmpty(fileName)) {
                    return;
                }
                
                String newName = fileName.substring(fileName.lastIndexOf(File.separator) + 1, fileName.length());
                for (int i = 0; i < arr.length; i++) {
                    if (newName.equals(arr[i].split(":")[0])) {
                        newName = arr[i].split(":")[1];
                    }
                }
                
                BodyPart bp = new MimeBodyPart();
                bp.setDataHandler(new DataHandler(new FileDataSource(fileName)));
                bp.setFileName(MimeUtility.encodeText(newName));//附件名字乱码
                mp.addBodyPart(bp);
            }
        } catch(Exception e) {
            e.printStackTrace();
        }
    }