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(
                    "<meta http-equiv=content-type content=text/html; charset=utf-8>"
                            + 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<string> 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"));