struts2集成javamail发邮件示例详解

一、代码预览
这两天在做struts2上的邮件发送。以前的项目有用到spring，用spring提供的邮件支持类很方便可以完成这个功能，但是现在只用struts2的话，就碰到了一系列的问题。

请先将自己下载的 mail.jar，及activation.jar加入到classpath

package com.nerve.cloudoffice.common.util;

import java.util.List;
import java.util.Properties;

import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.Address;
import javax.mail.BodyPart;
import javax.mail.Message;
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 EMailSender {
     /**
     * 向用户发送邮件
     */
    private static final long serialVersionUID = 1L;

    private MimeMessage mimeMsg; // MIME邮件对象

    private Session session; // 邮件会话对象

    private Properties props; // 系统属性

    private boolean needAuth = false; // smtp是否需要认证

    private String username = ""; // smtp认证用户名和密码

    private String password = "";

    private Multipart mp; // Multipart对象,邮件内容,标题,附件等内容均添加到其中后再生成

    private String log;

    public EMailSender() {

    }

    public EMailSender(String smtp) {
        setSmtpHost(smtp);
        createMimeMessage();
    }

    public void setSmtpHost(String hostName) {
        System.out.println("设置系统属性：mail.smtp.host = "   hostName);
        if (props == null)
            props = System.getProperties(); // 获得系统属性对象
        props.put("mail.smtp.host", hostName); // 设置SMTP主机
        props.put("mail.smtp.localhost", "localHostAdress");
    }

    public boolean createMimeMessage() {
        try {
            System.out.println("准备获取邮件会话对象！");
            session = Session.getDefaultInstance(props, null); // 获得邮件会话对象
        } catch (Exception e) {
            log = "获取邮件会话对象时发生错误！"   e.toString();
            System.err.println(log);
            return false;
        }
        try {
            mimeMsg = new MimeMessage(session); // 创建MIME邮件对象
            mp = new MimeMultipart(); // mp 一个multipart对象
            // Multipart is a container that holds multiple body parts.
            return true;
        } catch (Exception e) {
            log = "创建MIME邮件对象失败！"   e;
            System.err.println(log);
            return false;
        }
    }

    public void setNeedAuth(boolean need) {
        System.out.println("设置smtp身份认证：mail.smtp.auth = "   need);
        if (props == null)
            props = System.getProperties();
        if (need) {
            props.put("mail.smtp.auth", "true");
        } else {
            props.put("mail.smtp.auth", "false");
        }
    }

    public void setNamePass(String name, String pass) {
        System.out.println("程序得到用户名与密码");
        username = name;
        password = pass;
    }

    public boolean setSubject(String mailSubject) {
        System.out.println("设置邮件主题！");
        try {
            mimeMsg.setSubject(MimeUtility.encodeText(mailSubject,"utf-8","B"));
            return true;
        } catch (Exception e) {
            log = "设置邮件主题发生错误！" e;
            System.err.println(log);
            return false;
        }
    }

    public boolean setBody(String mailBody) {
        try {
            System.out.println("设置邮件体格式");
            BodyPart bp = new MimeBodyPart();
            // 转换成中文格式
            bp.setContent(
                    ""
                              mailBody, "text/html;charset=utf-8");
            mp.addBodyPart(bp);
            return true;
        } catch (Exception e) {
            log = "设置邮件正文时发生错误！"   e;
            System.err.println(log);
            return false;
        }
    }

    public boolean setFiles(List files){
        try{
            for(String s:files){
                MimeBodyPart mbp=new MimeBodyPart();  
                FileDataSource fds=new FileDataSource(s); //得到数据源  
                mbp.setDataHandler(new DataHandler(fds)); //得到附件本身并至入BodyPart  
                mbp.setFileName(fds.getName());  //得到文件名同样至入BodyPart  
                mp.addBodyPart(mbp);
            }
            return true;
        }catch(Exception e){
            log = "增加附件时出错：" e;
            e.printStackTrace();
            return false;
        }
    }

    public boolean addFile(String path, String name){
        try{
            MimeBodyPart mbp=new MimeBodyPart();  
            FileDataSource fds=new FileDataSource(path); //得到数据源  
            mbp.setDataHandler(new DataHandler(fds)); //得到附件本身并至入BodyPart  
            mbp.setFileName(MimeUtility.encodeText(name,"utf-8","B"));
            mp.addBodyPart(mbp);
            return true;
        }catch(Exception e){
            log = "增加附件时出错：" e;
            e.printStackTrace();
            return false;
        }
    }

    public boolean setFrom(String from) {
        System.out.println("设置发信人！");
        try {
            mimeMsg.setFrom(new InternetAddress(from)); // 设置发信人
            return true;
        } catch (Exception e) {
            log = "设置发信人出错:" e;
            return false;
        }
    }

    public boolean setTo(String to) {
        System.out.println("设置收信人");
        if (to == null)
            return false;
        try {
            mimeMsg.setRecipients(Message.RecipientType.TO, InternetAddress
                    .parse(to));
            return true;
        } catch (Exception e) {
            return false;
        }
    }

    public boolean setCopyTo(String copyto) {
        if (copyto == null)
            return false;
        try {
            mimeMsg.setRecipients(Message.RecipientType.CC,
                    (Address[]) InternetAddress.parse(copyto));
            return true;
        } catch (Exception e) {
            return false;
        }
    }

    public boolean sendout() {
        try {
            mimeMsg.setContent(mp);
            mimeMsg.saveChanges();
            System.out.println("正在发送邮件....");
            Session mailSession = Session.getInstance(props, null);
            Transport transport = mailSession.getTransport("smtp");
            transport.connect((String) props.get("mail.smtp.host"), username,
                    password);
            transport.sendMessage(mimeMsg, mimeMsg
                    .getRecipients(Message.RecipientType.TO));
            // transport.send(mimeMsg);
            System.out.println("发送邮件成功！");
            transport.close();
            return true;
        } catch (Exception e) {
            log = "邮件发送失败！"   e;
            System.err.println(log);
            return false;
        }
    }

    public String getLog(){
        return log;
    }
}

二、问题总结

2.1  本地执行时报错

我用的是javaee 5，jdk1.6，在本地跑时，会出现ClassNotFound的Exception，但是这些类在mail.jar里面又是有的。这个原因是因为我们自己增加的jar包里面的类跟javaee5里面的冲突了，我推荐的解决方法是将javaee5里面的 activation包跟mail包删除。

做法如下：

找到eclipse引用的javaee5包，用rar软件打开，找到activation跟mail包，删除保存就可以了。（记得在ide中刷新一下引用包）

2.2 javax.mail.MessagingException: 501 Syntax: HELO hostname

在本地测试通过后，我部署到linux服务器中，但是去碰到了javax.mail.MessagingException: 501 Syntax: HELO hostname异常， google了发现是以下原因：

Javamail 在提取本地 hostname 的时候会 dig 改 hostname ，然后以改 ip 发送邮件。

由于 hostname 对应的 ip 地址， linux 无法解析（如果是 windows 则无这个问题， windows 利用 netbios 协议去获得该主机的 ip 地址）到本机 hostname 的 ip ，导致 javamail 无法调用发送 ip 。 Postfix 收到此类邮件将拒绝投递，而产生 501 错误。

网上说可以通过修改服务器的hosts文件解决，但是我发现还可以直接在代码里面解决（只需要加一行代码，这大大方便啊），即在setSmtpHost()方法中，增加下面一行：

props.put("mail.smtp.localhost", "localHostAdress");

2.3 附件中文名乱码
如果附件有中文名，直接setName（）会乱码，通过下面的方法可以解决：

mbp.setFileName(MimeUtility.encodeText(name,"utf-8","B"));