如何用java实现发邮件功能，并有几点注意事项

package com.victor;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
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;
import javax.mail.internet.MimeUtility;

public class JavaMailWithAttachment {
    private MimeMessage message;
    private Session session;
    private Transport transport;

    private String mailHost = "";
    private String sender_username = "";
    private String sender_password = "";


    private Properties properties = new Properties();
    /*
     * 初始化方法
     */
    public JavaMailWithAttachment(boolean debug) {
        InputStream in = JavaMailWithAttachment.class.getResourceAsStream("/MailServer.properties");
        try {
            properties.load(in);
            this.mailHost = properties.getProperty("mail.smtp.host");
            this.sender_username = properties.getProperty("mail.sender.username");
            this.sender_password = properties.getProperty("mail.sender.password");
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        session = Session.getInstance(properties);
        session.setDebug(debug);//开启后有调试信息
        message = new MimeMessage(session);
    }

    /**
     * 发送邮件
     *
     * @param subject
     *            邮件主题
     * @param sendHtml
     *            邮件内容
     * @param receiveUser
     *            收件人地址
     * @param attachment
     *            附件
     */
    public void doSendHtmlEmail(String subject, String sendHtml, String receiveUser, File attachment) {
        try {
            // 发件人
            InternetAddress from = new InternetAddress(sender_username);
            message.setFrom(from);

            // 收件人
            InternetAddress to = new InternetAddress(receiveUser);
            message.setRecipient(Message.RecipientType.TO, to);

            // 邮件主题
            message.setSubject(subject);

            // 向multipart对象中添加邮件的各个部分内容，包括文本内容和附件
            Multipart multipart = new MimeMultipart();
            
            // 添加邮件正文
            BodyPart contentPart = new MimeBodyPart();
            contentPart.setContent(sendHtml, "text/html;charset=UTF-8");
            multipart.addBodyPart(contentPart);
            
            // 添加附件的内容
            if (attachment != null) {
                BodyPart attachmentBodyPart = new MimeBodyPart();
                DataSource source = new FileDataSource(attachment);
                attachmentBodyPart.setDataHandler(new DataHandler(source));
                
                // 网上流传的解决文件名乱码的方法，其实用MimeUtility.encodeWord就可以很方便的搞定
                // 这里很重要，通过下面的Base64编码的转换可以保证你的中文附件标题名在发送时不会变成乱码
                //sun.misc.BASE64Encoder enc = new sun.misc.BASE64Encoder();
                //messageBodyPart.setFileName("=?GBK?B?" + enc.encode(attachment.getName().getBytes()) + "?=");
                
                //MimeUtility.encodeWord可以避免文件名乱码
                attachmentBodyPart.setFileName(MimeUtility.encodeWord(attachment.getName()));
                multipart.addBodyPart(attachmentBodyPart);
            }
            
            // 将multipart对象放到message中
            message.setContent(multipart);
            // 保存邮件
            message.saveChanges();

            transport = session.getTransport("smtp");
            // smtp验证，就是你用来发邮件的邮箱用户名密码
            transport.connect(mailHost, sender_username, sender_password);
            // 发送
            transport.sendMessage(message, message.getAllRecipients());

            System.out.println("send success!");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (transport != null) {
                try {
                    transport.close();
                } catch (MessagingException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) {
        JavaMailWithAttachment se = new JavaMailWithAttachment(true);
        System.out.println(se);
        File affix = new File("E:\\测试-test.txt");
      //  File affix =null;
        se.doSendHtmlEmail("##", "###", "####@##.com", affix);//
    }
}

注意点：1 jar可能有冲突，如果是demo可以直接应用mail.jar

如果是一个工程则要替换javaEE中的mail.jar包

2 关于properties配置文件的地址问题

Class.getResourceAsStream(String path) ： path 不以’/'开头时默认是从此类所在的包下取资源，以’/'开头则是从

ClassPath根下获取。其只是通过path构造一个绝对路径，最终还是由ClassLoader获取资源。

明天要将这个小功能加入模块中间，小兴奋啊