用Java Socket实现SMTP邮件发送

什么是SMTP？

  SMTP（Simple Mail Transfer Protocol）即简单邮件传输协议，它是一种提供可靠且有效电子邮件传输的协议。SMTP是建模在FTP文件传输服务上的一种邮件服务，主要用于传输系统之间的邮件信息并提供来信有关的通知。



协议结构

  SMTP命令是发送于SMTP主机之间的ASCII信息，下面列举了5个常用SMTP指令

HELO <服务商><域名><换行> 与SMTP服务器握手
MAIL <服务商> FROM:<发件人地址><换行> 传送发件人的邮箱地址
RCPT <服务商> TO:<收件人地址><换行>  传送收件人的邮箱地址
DATA <换行> 发送邮件数据，以新行.结束（包括信头与信体）
QUIT <换行> 与SMTP服务器断开连接



信头与信体

  在DATA指令所传送的数据中，信头和信体以一个空行分隔，下面列举了部分常用信头

From: 发件人地址
To: 收件人地址
Subject: 邮件主题
Date: 发信时间
MIME-Version: MIME版本
Content-Type: 内容类型
Content-Transfer-Encoding: 编码方式
X-Priority: 优先级
X-Mailer: 代理发信的客户端



通过Socket发送SMTP邮件

1.Base64

  Base64内容传送编码被设计用来把任意序列的8位字节描述为一种不易被人直接识别的形式，它要求把每三个8位的字节转换为四个6位的字节，然后在6位字节的高位补两个0，最后组成四个8位的字节。在发送电子邮件时，服务器认证的用户名和密码需要用Base64编码，附件也需要用Base64编码。这种加密方式并非绝对安全，只能做到让人不能直接看出原本内容而已。

一个用Java实现的Base64的加/解密类

package org.gameeden.security;

import java.io.ByteArrayOutputStream;

/**
 * Base64编码/解码器。
 * @author Sol
 */
public class Base64
{
    private final static char[] BASE64_ENCODING_TABLE;
    private final static byte[] BASE64_DECODING_TABLE;

    static 
    {
        BASE64_ENCODING_TABLE="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
        BASE64_DECODING_TABLE=new byte[]
        {
            -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
            -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-1,-1,-1,
            -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
            -1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1
        };
    }
    
    private Base64()
    { 
    }
    
    /**
     * 将数据进行Base64编码。
     * @param data 数据
     * @param offset 数据中的初始偏移量
     * @param length 写入的字节数
     * @return 编码后的字符串
     */
    public final static String encode(byte[] data,int offset,int length)
    {
        if(data==null)
        {
            return null;
        }
        
        StringBuffer buffer=new StringBuffer();
        int[] temp=new int[3];
        int end=offset+length;
        
        while(offset<end)
        {            
            temp[0]=data[offset++]&255;
            
            if(offset==data.length)
            {
                buffer.append(BASE64_ENCODING_TABLE[(temp[0]>>>2)&63]);
                buffer.append(BASE64_ENCODING_TABLE[(temp[0]<<4)&63]);
                buffer.append('=');
                buffer.append('=');
                
                break;
            }
            
            temp[1]=data[offset++]&255;
            
            if(offset==data.length)
            {
                buffer.append(BASE64_ENCODING_TABLE[(temp[0]>>>2)&63]);
                buffer.append(BASE64_ENCODING_TABLE[((temp[0]<<4)|(temp[1]>>>4))&63]);
                buffer.append(BASE64_ENCODING_TABLE[(temp[1]<<2)&63]);
                buffer.append('=');
                
                break;
            }
            
            temp[2]=data[offset++]&255;
            
            buffer.append(BASE64_ENCODING_TABLE[(temp[0]>>>2)&63]);
            buffer.append(BASE64_ENCODING_TABLE[((temp[0]<<4)|(temp[1]>>>4))&63]);
            buffer.append(BASE64_ENCODING_TABLE[((temp[1]<<2)|(temp[2]>>>6))&63]);
            buffer.append(BASE64_ENCODING_TABLE[temp[2]&63]);
        }
        
        return buffer.toString();
    }
    
    /**
     * 将数据进行Base64编码。
     * @param data 数据
     * @return 编码后的字符串
     */
    public final static String encode(byte[] data)
    {
        return encode(data,0,data.length);
    }

    /**
     * 将字符串进行Base64编码。
     * @param str 字符串
     * @return 编码后的字符串
     */
    public final static String encode(String str)
    {
        return encode(str.getBytes());
    }
    
    /**
     * 对使用Base64编码的字符串进行解码。
     * @param str 经过编码的字符串
     * @return 解码后的数据
     */
    public final static byte[] decode(String str)
    {
        if(str==null)
        {
            return null;
        }

        ByteArrayOutputStream buffer=new ByteArrayOutputStream();
        byte[] data=str.getBytes();
        int[] temp=new int[4];
        int index=0;
        
        while(index<data.length)
        {
            do
            {
                temp[0]=BASE64_DECODING_TABLE[data[index++]];
            }while(index<data.length&&temp[0]==-1);
            
            if(temp[0]==-1)
            {
                break;
            }

            do
            {
                temp[1]=BASE64_DECODING_TABLE[data[index++]];
            }while(index<data.length&&temp[1]==-1);
            
            if(temp[1]==-1)
            {
                break;
            }
            
            buffer.write(((temp[0]<<2)&255)|((temp[1]>>>4)&255));

            do
            {
                temp[2]=data[index++];
                
                if(temp[2]==61)
                {
                    return buffer.toByteArray();
                }
                
                temp[2]=BASE64_DECODING_TABLE[temp[2]];
            }while(index<data.length&&temp[2]==-1);
            
            if(temp[2]==-1)
            {
                break;
            }
            
            buffer.write(((temp[1]<<4)&255)|((temp[2]>>>2)&255));

            do
            {
                temp[3]=data[index++];
                
                if(temp[3]==61)
                {
                    return buffer.toByteArray();
                }
                
                temp[3]=BASE64_DECODING_TABLE[temp[3]];
            }while(index<data.length&&temp[3]==-1);
            
            if(temp[3]==-1)
            {
                break;
            }
            
            buffer.write(((temp[2]<<6)&255)|temp[3]);
        }
        
        return buffer.toByteArray();
    }
}

2.MIME类型

  MIME意为多目Internet邮件扩展，它设计的最初目的是为了在发送电子邮件时附加多媒体数据，让邮件客户程序能根据其类型进行处理。每个MIME类型由两部分组成，前面是数据的大类别，后面为具体的种类。例如：image/bmp、image/jpeg、audio/mpeg

一个用于获取各种后缀名所对应MIME类型的工具类（MIME类型列表本来是存储在XML文件中的，此类的作用是读取XML中的数据，由于本文并不打算介绍XML解析，所以直接将数据写到了代码里）

package org.gameeden.mail;

import java.util.Hashtable;

/**
 * 用于获得MIME类型的工具类。
 * @author Sol
 * @since 1.5
 */
public final class MimeTypeFactory
{
    private final static Hashtable<String,String> mimeTypes;
    
    static
    {
        mimeTypes=new Hashtable<String,String>();
        
        mimeTypes.put("*","application/octet-stream");
        mimeTypes.put("323","text/h323");
        mimeTypes.put("acx","application/internet-property-stream");
        mimeTypes.put("ai","application/postscript");
        mimeTypes.put("aif","audio/x-aiff");
        mimeTypes.put("aifc","audio/x-aiff");
        mimeTypes.put("aiff","audio/x-aiff");
        mimeTypes.put("asf","video/x-ms-asf");
        mimeTypes.put("asr","video/x-ms-asf");
        mimeTypes.put("asx","video/x-ms-asf");
        mimeTypes.put("au","audio/basic");
        mimeTypes.put("avi","video/x-msvideo");
        mimeTypes.put("axs","application/olescript");
        mimeTypes.put("bas","text/plain");
        mimeTypes.put("bcpio","application/x-bcpio");
        mimeTypes.put("bin","application/octet-stream");
        mimeTypes.put("bmp","image/bmp");
        mimeTypes.put("c","text/plain");
        mimeTypes.put("cat","application/vnd.ms-pkiseccat");
        mimeTypes.put("cdf","application/x-cdf");
        mimeTypes.put("cer","application/x-x509-ca-cert");
        mimeTypes.put("class","application/octet-stream");
        mimeTypes.put("clp","application/x-msclip");
        mimeTypes.put("cmx","image/x-cmx");
        mimeTypes.put("cod","image/cis-cod");
        mimeTypes.put("cpio","application/x-cpio");
        mimeTypes.put("crd","application/x-mscardfile");
        mimeTypes.put("crl","application/pkix-crl");
        mimeTypes.put("crt","application/x-x509-ca-cert");
        mimeTypes.put("csh","application/x-csh");
        mimeTypes.put("css","text/css");
        mimeTypes.put("dcr","application/x-director");
        mimeTypes.put("der","application/x-x509-ca-cert");
        mimeTypes.put("dir","application/x-director");
        mimeTypes.put("dll","application/x-msdownload");
        mimeTypes.put("dms","application/octet-stream");
        mimeTypes.put("doc","application/msword");
        mimeTypes.put("dot","application/msword");
        mimeTypes.put("dvi","application/x-dvi");
        mimeTypes.put("dxr","application/x-director");
        mimeTypes.put("eps","application/postscript");
        mimeTypes.put("etx","text/x-setext");
        mimeTypes.put("evy","application/envoy");
        mimeTypes.put("exe","application/octet-stream");
        mimeTypes.put("fif","application/fractals");
        mimeTypes.put("flr","x-world/x-vrml");
        mimeTypes.put("gif","image/gif");
        mimeTypes.put("gtar","application/x-gtar");
        mimeTypes.put("gz","application/x-gzip");
        mimeTypes.put("h","text/plain");
        mimeTypes.put("hdf","application/x-hdf");
        mimeTypes.put("hlp","application/winhlp");
        mimeTypes.put("hqx","application/mac-binhex40");
        mimeTypes.put("hta","application/hta");
        mimeTypes.put("htc","text/x-component");
        mimeTypes.put("htm","text/html");
        mimeTypes.put("html","text/html");
        mimeTypes.put("htt","text/webviewhtml");
        mimeTypes.put("ico","image/x-icon");
        mimeTypes.put("ief","image/ief");
        mimeTypes.put("iii","application/x-iphone");
        mimeTypes.put("ins","application/x-internet-signup");
        mimeTypes.put("isp","application/x-internet-signup");
        mimeTypes.put("jfif","image/pipeg");
        mimeTypes.put("jpe","image/jpeg");
        mimeTypes.put("jpeg","image/jpeg");
        mimeTypes.put("jpg","image/jpeg");
        mimeTypes.put("js","application/x-javascript");
        mimeTypes.put("latex","application/x-latex");
        mimeTypes.put("lha","application/octet-stream");
        mimeTypes.put("lsf","video/x-la-asf");
        mimeTypes.put("lsx","video/x-la-asf");
        mimeTypes.put("lzh","application/octet-stream");
        mimeTypes.put("m13","application/x-msmediaview");
        mimeTypes.put("m14","application/x-msmediaview");
        mimeTypes.put("m3u","audio/x-mpegurl");
        mimeTypes.put("man","application/x-troff-man");
        mimeTypes.put("mdb","application/x-msaccess");
        mimeTypes.put("me","application/x-troff-me");
        mimeTypes.put("mht","message/rfc822");
        mimeTypes.put("mhtml","message/rfc822");
        mimeTypes.put("mid","audio/mid");
        mimeTypes.put("mny","application/x-msmoney");
        mimeTypes.put("mov","video/quicktime");
        mimeTypes.put("movie","video/x-sgi-movie");
        mimeTypes.put("mp2","video/mpeg");
        mimeTypes.put("mp3","audio/mpeg");
        mimeTypes.put("mpa","video/mpeg");
        mimeTypes.put("mpe","video/mpeg");
        mimeTypes.put("mpeg","video/mpeg");
        mimeTypes.put("mpg","video/mpeg");
        mimeTypes.put("mpp","application/vnd.ms-project");
        mimeTypes.put("mpv2","video/mpeg");
        mimeTypes.put("ms","application/x-troff-ms");
        mimeTypes.put("mvb","application/x-msmediaview");
        mimeTypes.put("nws","message/rfc822");
        mimeTypes.put("oda","application/oda");
        mimeTypes.put("p10","application/pkcs10");
        mimeTypes.put("p12","application/x-pkcs12");
        mimeTypes.put("p7b","application/x-pkcs7-certificates");
        mimeTypes.put("p7c","application/x-pkcs7-mime");
        mimeTypes.put("p7m","application/x-pkcs7-mime");
        mimeTypes.put("p7r","application/x-pkcs7-certreqresp");
        mimeTypes.put("p7s","application/x-pkcs7-signature");
        mimeTypes.put("pbm","image/x-portable-bitmap");
        mimeTypes.put("pdf","application/pdf");
        mimeTypes.put("pfx","application/x-pkcs12");
        mimeTypes.put("pgm","image/x-portable-graymap");
        mimeTypes.put("pko","application/ynd.ms-pkipko");
        mimeTypes.put("pma","application/x-perfmon");
        mimeTypes.put("pmc","application/x-perfmon");
        mimeTypes.put("pml","application/x-perfmon");
        mimeTypes.put("pmr","application/x-perfmon");
        mimeTypes.put("pmw","application/x-perfmon");
        mimeTypes.put("pnm","image/x-portable-anymap");
        mimeTypes.put("pot,","application/vnd.ms-powerpoint");
        mimeTypes.put("ppm","image/x-portable-pixmap");
        mimeTypes.put("pps","application/vnd.ms-powerpoint");
        mimeTypes.put("ppt","application/vnd.ms-powerpoint");
        mimeTypes.put("prf","application/pics-rules");
        mimeTypes.put("ps","application/postscript");
        mimeTypes.put("pub","application/x-mspublisher");
        mimeTypes.put("qt","video/quicktime");
        mimeTypes.put("ra","audio/x-pn-realaudio");
        mimeTypes.put("ram","audio/x-pn-realaudio");
        mimeTypes.put("ras","image/x-cmu-raster");
        mimeTypes.put("rgb","image/x-rgb");
        mimeTypes.put("rmi","audio/mid");
        mimeTypes.put("roff","application/x-troff");
        mimeTypes.put("rtf","application/rtf");
        mimeTypes.put("rtx","text/richtext");
        mimeTypes.put("scd","application/x-msschedule");
        mimeTypes.put("sct","text/scriptlet");
        mimeTypes.put("setpay","application/set-payment-initiation");
        mimeTypes.put("setreg","application/set-registration-initiation");
        mimeTypes.put("sh","application/x-sh");
        mimeTypes.put("shar","application/x-shar");
        mimeTypes.put("sit","application/x-stuffit");
        mimeTypes.put("snd","audio/basic");
        mimeTypes.put("spc","application/x-pkcs7-certificates");
        mimeTypes.put("spl","application/futuresplash");
        mimeTypes.put("src","application/x-wais-source");
        mimeTypes.put("sst","application/vnd.ms-pkicertstore");
        mimeTypes.put("stl","application/vnd.ms-pkistl");
        mimeTypes.put("stm","text/html");
        mimeTypes.put("sv4cpio","application/x-sv4cpio");
        mimeTypes.put("sv4crc","application/x-sv4crc");
        mimeTypes.put("t","application/x-troff");
        mimeTypes.put("tar","application/x-tar");
        mimeTypes.put("tcl","application/x-tcl");
        mimeTypes.put("tex","application/x-tex");
        mimeTypes.put("texi","application/x-texinfo");
        mimeTypes.put("texinfo","application/x-texinfo");
        mimeTypes.put("tgz","application/x-compressed");
        mimeTypes.put("tif","image/tiff");
        mimeTypes.put("tiff","image/tiff");
        mimeTypes.put("tr","application/x-troff");
        mimeTypes.put("trm","application/x-msterminal");
        mimeTypes.put("tsv","text/tab-separated-values");
        mimeTypes.put("txt","text/plain");
        mimeTypes.put("uls","text/iuls");
        mimeTypes.put("ustar","application/x-ustar");
        mimeTypes.put("vcf","text/x-vcard");
        mimeTypes.put("vrml","x-world/x-vrml");
        mimeTypes.put("wav","audio/x-wav");
        mimeTypes.put("wcm","application/vnd.ms-works");
        mimeTypes.put("wdb","application/vnd.ms-works");
        mimeTypes.put("wks","application/vnd.ms-works");
        mimeTypes.put("wmf","application/x-msmetafile");
        mimeTypes.put("wps","application/vnd.ms-works");
        mimeTypes.put("wri","application/x-mswrite");
        mimeTypes.put("wrl","x-world/x-vrml");
        mimeTypes.put("wrz","x-world/x-vrml");
        mimeTypes.put("xaf","x-world/x-vrml");
        mimeTypes.put("xbm","image/x-xbitmap");
        mimeTypes.put("xla","application/vnd.ms-excel");
        mimeTypes.put("xlc","application/vnd.ms-excel");
        mimeTypes.put("xlm","application/vnd.ms-excel");
        mimeTypes.put("xls","application/vnd.ms-excel");
        mimeTypes.put("xlt","application/vnd.ms-excel");
        mimeTypes.put("xlw","application/vnd.ms-excel");
        mimeTypes.put("xof","x-world/x-vrml");
        mimeTypes.put("xpm","image/x-xpixmap");
        mimeTypes.put("xwd","image/x-xwindowdump");
        mimeTypes.put("z","application/x-compress");
        mimeTypes.put("zip","application/zip");
    }
    
    private MimeTypeFactory()
    {
    }
    
    /**
     * 设置MIME类型。
     * @param postfix 文件后缀名
     * @param mimeType MIME类型
     * @return 以前的MIME类型
     */
    public static String setMimeType(String postfix,String mimeType)
    {
        Object result=mimeTypes.put(postfix.toLowerCase(),mimeType);
            
        return result==null?(String)getMimeType("*"):(String)result;
    }
    
    /**
     * 获得MIME类型。
     * @param postfix 文件后缀名
     * @return MIME类型
     */
    public static String getMimeType(String postfix)
    {
        Object result=mimeTypes.get(postfix.toLowerCase());
        
        return result==null?(String)getMimeType("*"):(String)result;
    }
}

3.SMTP邮件发送实例

日志管理器

package org.gameeden.util;

/**
 * 日志管理器。
 * @author Sol
 */
public interface LogManager
{
    /**
     * 输出。
     * @param info 信息
     */
    public void output(String info);
}

用Socket实现的SMTP邮件发送类

package org.gameeden.mail;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.net.Socket;
import java.net.SocketTimeoutException;
import java.nio.charset.Charset;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Hashtable;
import java.util.Locale;
import java.util.regex.Pattern;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.InitialDirContext;

import org.gameeden.security.Base64;
import org.gameeden.util.LogManager;

/**
 * SMTP邮件发送系统。
 * 
 * 
 * 发件人和收件人的正确格式如下:
 * 
 * 例1: "Sol"<[e-mail]>
 * 例2: Sol<[e-mail]>
 * 例3: <[e-mail]>
 * 例4: [e-mail]
 * 
 * @author Sol
 * @since 1.5
 */
public final class SmtpMailSender
{
    /**
     * 发送成功的常量。
     */
    public final static boolean SUCCESSFUL=true;
    
    /**
     * 发送失败的常量。
     */
    public final static boolean FAILED=false;
    
    private final static int PORT=25;//服务器端口(SMTP服务器和邮件接收服务器的端口均为25)
    private final static int RETRY=3;//当连接SMTP服务器失败后尝试重新连接的次数(仅用于发送ESMTP邮件)
    private final static int INTERVAL=1000;//当连接SMTP服务器失败后重新连接的时间间隔(仅用于发送ESMTP邮件)
    private final static int TIMEOUT=10000;//网络连接的超时时间
    
    private final static String BOUNDARY;//MIME分格符
    private final static String CHARSET;//虚拟机的默认编码
    private final static Pattern PATTERN;//用于效验邮箱地址的正确性
    
    private static InitialDirContext dirContext;//用于查询DNS记录
    
    private final ArrayList<LogManager> logManager;//日志管理器
    
    private boolean isEsmtp;//发送类型
    
    private String smtp;//SMTP服务器地址(仅用于发送ESMTP邮件)
    private String user;//用户名(仅用于发送ESMTP邮件)
    private String password;//密码(仅用于发送ESMTP邮件)
    private String sender;//发件人名字
    private String senderAddress;//发件人的E-Mail地址
    
    static
    {
        BOUNDARY="Boundary-=_hMbeqwnGNoWeLsRMeKTIPeofyStu";
        CHARSET=Charset.defaultCharset().displayName();
        PATTERN=Pattern.compile(".+@[^.@]+(\\.[^.@]+)+$");//此处放弃了传统匹配方式，这是为了兼容非英文域名的电子邮箱
        
        Hashtable<String,String> hashtable=new Hashtable<String,String>();
        hashtable.put("java.naming.factory.initial","com.sun.jndi.dns.DnsContextFactory");
        
        try
        {
            dirContext=new InitialDirContext(hashtable);
        }
        catch(NamingException e)
        {
        }
    }
    
    private SmtpMailSender(String from)
    {
        if(from==null)
        {
            throw new IllegalArgumentException("参数from不能为null。");
        }
        
        int leftSign=(from=from.trim()).charAt(from.length()-1)=='>'?from.lastIndexOf('<'):-1;
        
        senderAddress=leftSign>-1?from.substring(leftSign+1,from.length()-1).trim():from;
        
        if(!PATTERN.matcher(senderAddress).find())
        {
            throw new IllegalArgumentException("参数from不正确。");
        }
        
        sender=leftSign>-1?from.substring(0,leftSign).trim():null;
        logManager=new ArrayList<LogManager>();
        isEsmtp=false;
        
        if(sender!=null)
        {
            if(sender.length()==0)
            {
                sender=null;
            }
            else if(sender.charAt(0)=='"'&&sender.charAt(sender.length()-1)=='"')
            {
                sender=sender.substring(1,sender.length()-1).trim();
            }
        }
    }
    
    private SmtpMailSender(String address,String from,String user,String password)
    {
        this(from);
        
        isEsmtp=true;
        this.smtp=address;
        this.user=Base64.encode(user.getBytes());
        this.password=Base64.encode(password.getBytes());
    }

    /**
     * 创建SMTP邮件发送系统实例。
     * @param from 发件人
     * @return SMTP邮件发送系统的实例
     * @throws IllegalArgumentException 如果参数from为null或格式不正确
     */
    public static SmtpMailSender createSmtpMailSender(String from) throws IllegalArgumentException
    {
        return new SmtpMailSender(from);
    }
    
    /**
     * 创建ESMTP邮件发送系统实例。
     * @param smtp SMTP服务器地址
     * @param from 发件人
     * @param user 用户名
     * @param password 密码
     * @return SMTP邮件发送系统的实例
     * @throws IllegalArgumentException 如果参数from为null或格式不正确
     */
    public static SmtpMailSender createESmtpMailSender(String smtp,String from,String user,String password) throws IllegalArgumentException
    {
        return new SmtpMailSender(smtp,from,user,password);
    }
    
    /**
     * 发送邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @param attachments 附件
     * @param isHtml 使用网页形式发送
     * @param isUrgent 紧急邮件
     * @return 是否发送成功
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean sendMail(String to,String subject,String content,File[] attachments,boolean isHtml,boolean isUrgent) throws IllegalArgumentException
    {
        if(to==null)
        {
            throw new IllegalArgumentException("参数to不能为null。");
        }
        
        int leftSign=(to=to.trim()).charAt(to.length()-1)=='>'?to.lastIndexOf('<'):-1;
        
        String addresseeAddress=leftSign>-1?to.substring(leftSign+1,to.length()-1).trim():to;//收件人的E-Mail地址

        if(!PATTERN.matcher(addresseeAddress).find())
        {
            throw new IllegalArgumentException("参数to不正确。");
        }
        
        String addressee=leftSign>-1?to.substring(0,leftSign).trim():null;//收件人名字
        boolean needBoundary=attachments!=null&&attachments.length>0;
        
        Socket socket=null;
        InputStream in=null;
        OutputStream out=null;
        byte[] data;

        try
        {   
            if(addressee!=null)
            {
                if(addressee.length()==0)
                {
                    addressee=null;
                }
                else if(addressee.charAt(0)=='"'&&addressee.charAt(addressee.length()-1)=='"')
                {
                    addressee=addressee.substring(1,addressee.length()-1).trim();
                }
            }
            
            if(isEsmtp)
            {
                for(int k=1;;k++)
                {
                    try
                    {
                        log("连接: 主机:\""+smtp+"\" 端口:\""+PORT+"\"");
                        socket=new Socket(smtp,PORT);
                        break;
                    }
                    catch(IOException e)
                    {
                        log("错误: 连接失败"+k+"次");

                        if(k==RETRY)
                        {
                            return FAILED;
                        }
                        
                        try
                        {
                            Thread.sleep(INTERVAL);
                        }
                        catch(InterruptedException ie)
                        {
                        }
                    }
                }

                in=socket.getInputStream();
                out=socket.getOutputStream();
                
                if(response(in)!=220)
                {
                    return FAILED;
                }
            }
            else
            {
                log("状态: 创建邮件接收服务器列表");
                String[] address=parseDomain(parseUrl(addresseeAddress));
                
                if(address==null)
                {
                    return FAILED;
                }
                
                for(int k=0;k<address.length;k++)
                {
                    try
                    {
                        log("连接: 主机:\""+address[k]+"\" 端口:\""+PORT+"\"");

                        socket=new Socket(address[k],PORT);
    
                        in=socket.getInputStream();
                        out=socket.getOutputStream();
                        
                        if(response(in)!=220)
                        {
                            return FAILED;
                        }
                        
                        break;
                    }
                    catch(IOException e)
                    {
                        log("错误: 连接失败");
                    }
                }
            }

            if(in==null||out==null)
            {
                return FAILED;
            }
            
            socket.setSoTimeout(TIMEOUT);
            
            sendString("HELO "+parseUrl(senderAddress),out);
            sendNewline(out);
            
            if(response(in)!=250)
            {
                return FAILED;
            }

            if(isEsmtp)
            {
                sendString("AUTH LOGIN",out);
                sendNewline(out);
                
                if(response(in)!=334)
                {
                    return FAILED;
                }
                
                sendString(user,out);
                sendNewline(out);
                
                if(response(in)!=334)
                {
                    return FAILED;
                }
                
                sendString(password,out);
                sendNewline(out);
                
                if(response(in)!=235)
                {
                    return FAILED;
                }
            }
            
            sendString("MAIL FROM: <"+senderAddress+">",out);
            sendNewline(out);

            if(response(in)!=250)
            {
                return FAILED;
            }
            
            sendString("RCPT TO: <"+addresseeAddress+">",out);
            sendNewline(out);
            
            if(response(in)!=250)
            {
                return FAILED;
            }

            sendString("DATA",out);
            sendNewline(out);

            if(response(in)!=354)
            {
                return FAILED;
            }

            sendString("From: "+(sender==null?senderAddress:getBase64String(sender)+" <"+senderAddress+">"),out);
            sendNewline(out);
            sendString("To: "+(addressee==null?addresseeAddress:getBase64String(addressee)+" <"+addresseeAddress+">"),out);
            sendNewline(out);
            sendString("Subject: "+getBase64String(subject),out);
            sendNewline(out);
            sendString("Date: "+new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z (z)",Locale.US).format(new Date()),out);
            sendNewline(out);
            sendString("MIME-Version: 1.0",out);
            sendNewline(out);
            
            if(needBoundary)
            {
                sendString("Content-Type: multipart/mixed; BOUNDARY=\""+BOUNDARY+"\"",out);
                sendNewline(out);
            }
            else
            {
                if(isHtml)
                {
                    sendString("Content-Type: text/html; charset=\""+CHARSET+"\"",out);
                    sendNewline(out);
                }
                else
                {
                    sendString("Content-Type: text/plain; charset=\""+CHARSET+"\"",out);
                    sendNewline(out);
                }
            }
            
            sendString("Content-Transfer-Encoding: base64",out);
            sendNewline(out);

            if(isUrgent)
            {
                sendString("X-Priority: 1",out);
                sendNewline(out);
            }
            else
            {
                sendString("X-Priority: 3",out);
                sendNewline(out);
            }
            
            sendString("X-Mailer: BlackFox Mail[Copyright(C) 2007 Sol]",out);
            sendNewline(out);
            
            log("发送: ");
            sendNewline(out);

            if(needBoundary)
            {
                sendString("--"+BOUNDARY,out);
                sendNewline(out);
                
                if(isHtml)
                {
                    sendString("Content-Type: text/html; charset=\""+CHARSET+"\"",out);
                    sendNewline(out);
                }
                else
                {
                    sendString("Content-Type: text/plain; charset=\""+CHARSET+"\"",out);
                    sendNewline(out);
                }
                
                sendString("Content-Transfer-Encoding: base64",out);
                sendNewline(out);
                
                log("发送: ");
                sendNewline(out);
            }
            
            data=(content!=null?content:"").getBytes();
            
            for(int k=0;k<data.length;k+=54)
            {
                sendString(Base64.encode(data,k,Math.min(data.length-k,54)),out);
                sendNewline(out);
            }

            if(needBoundary)
            {
                RandomAccessFile attachment=null;
                int fileIndex=0;
                String fileName;
                int k;
                data=new byte[54];
                
                try
                {
                    for(;fileIndex<attachments.length;fileIndex++)
                    {
                        fileName=attachments[fileIndex].getName();
                        attachment=new RandomAccessFile(attachments[fileIndex],"r");

                        sendString("--"+BOUNDARY,out);
                        sendNewline(out);
                        sendString("Content-Type: "+MimeTypeFactory.getMimeType(fileName.indexOf(".")==-1?"*":fileName.substring(fileName.lastIndexOf(".")+1))+"; name=\""+(fileName=getBase64String(fileName))+"\"",out);
                        sendNewline(out);
                        sendString("Content-Transfer-Encoding: base64",out);
                        sendNewline(out);
                        sendString("Content-Disposition: attachment; filename=\""+fileName+"\"",out);
                        sendNewline(out);
                        
                        log("发送: ");
                        sendNewline(out);
                        
                        do
                        {
                            k=attachment.read(data,0,54);
                            
                            if(k==-1)
                            {
                                break;
                            }
                            
                            sendString(Base64.encode(data,0,k),out);
                            sendNewline(out);
                        }while(k==54);
                    }
                }
                catch(FileNotFoundException e)
                {
                    log("错误: 附件\""+attachments[fileIndex].getAbsolutePath()+"\"不存在");
                    return FAILED;
                }
                catch(IOException e)
                {
                    log("错误: 无法读取附件\""+attachments[fileIndex].getAbsolutePath()+"\"");
                    return FAILED;
                }
                finally
                {
                    if(attachment!=null)
                    {
                        try
                        {
                            attachment.close();
                        }
                        catch(IOException e)
                        {
                        }
                    }
                }
                
                sendString("--"+BOUNDARY+"--",out);
                sendNewline(out);
            }
            
            sendString(".",out);
            sendNewline(out);

            if(response(in)!=250)
            {
                return FAILED;
            }

            sendString("QUIT",out);
            sendNewline(out);

            if(response(in)!=221)
            {
                return FAILED;
            }
            
            return SUCCESSFUL;
        }
        catch(SocketTimeoutException e)
        {
            log("错误: 连接超时");
            return FAILED;
        }
        catch(IOException e)
        {
            log("错误: 连接出错");
            return FAILED;
        }
        catch(Exception e)
        {
            log("错误: "+e.toString());
            return FAILED;
        }
        finally
        {
            if(in!=null)
            {
                try
                {
                    in.close();
                }
                catch(IOException e)
                {
                }
            }
            
            if(out!=null)
            {
                try
                {
                    out.close();
                }
                catch(IOException e)
                {
                }
            }

            if(socket!=null)
            {
                try
                {
                    socket.close();
                }
                catch(IOException e)
                {
                }
            }
        }
    }
    
    /**
     * 给多个发件人发送邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @param attachments 附件
     * @param isHtml 使用网页形式发送
     * @param isUrgent 紧急邮件
     * @return 任务状况
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean[] sendMail(String[] to,String subject,String content,File[] attachments,boolean isHtml,boolean isUrgent) throws IllegalArgumentException
    {
        boolean[] task=new boolean[to.length];
        
        for(int k=0;k<task.length;k++)
        {
            task[k]=sendMail(to[k],subject,content,attachments,isHtml,isUrgent);
        }
        
        return task;
    }

    /**
     * 发送纯文本邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @return 是否发送成功
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean sendTextMail(String to,String subject,String content) throws IllegalArgumentException
    {
        return sendMail(to,subject,content,null,false,false);
    }
    
    /**
     * 发送HTML邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @return 是否发送成功
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean sendHtmlMail(String to,String subject,String content) throws IllegalArgumentException
    {
        return sendMail(to,subject,content,null,true,false);
    }
    
    /**
     * 给多个发件人发送纯文本邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @return 任务状况
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean[] sendTextMail(String[] to,String subject,String content) throws IllegalArgumentException
    {
        return sendMail(to,subject,content,null,false,false);
    }
    
    /**
     * 给多个发件人发送HTML邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @return 任务状况
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean[] sendHtmlMail(String[] to,String subject,String content) throws IllegalArgumentException
    {
        return sendMail(to,subject,content,null,true,false);
    }
    
    /**
     * 发送带附件的纯文本邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @param attachments 附件
     * @return 是否发送成功
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean sendTextMail(String to,String subject,String content,File[] attachments) throws IllegalArgumentException
    {
        return sendMail(to,subject,content,attachments,false,false);
    }
    
    /**
     * 发送带附件的HTML邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @param attachments 附件
     * @return 是否发送成功
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean sendHtmlMail(String to,String subject,String content,File[] attachments) throws IllegalArgumentException
    {
        return sendMail(to,subject,content,attachments,true,false);
    }
    
    /**
     * 给多个发件人发送带附件的纯文本邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @param attachments 附件
     * @return 任务状况
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean[] sendTextMail(String[] to,String subject,String content,File[] attachments) throws IllegalArgumentException
    {
        return sendMail(to,subject,content,attachments,false,false);
    }
    
    /**
     * 给多个发件人发送带附件的HTML邮件。
     * @param to 收件人
     * @param subject 主题
     * @param content 正文
     * @param attachments 附件
     * @return 任务状况
     * @throws IllegalArgumentException 如果参数to为null或格式不正确
     */
    public boolean[] sendHtmlMail(String[] to,String subject,String content,File[] attachments) throws IllegalArgumentException
    {
        return sendMail(to,subject,content,attachments,true,false);
    }

    /**
     * 添加一个日志管理器。
     * @param manager 日志管理器
     */
    public void addLogManager(LogManager manager)
    {
        logManager.add(manager);
    }
    
    /**
     * 移除日志管理器。
     * @param manager 要移除的日志管理器
     */
    public void removeLogManager(LogManager manager)
    {
        logManager.remove(manager);
    }
    
    /**
     * 通过分析收件人邮箱域名的DNS记录获取邮件接收服务器地址。
     * @param url 收件人邮箱域名
     * @return 主机地址列表
     */
    private String[] parseDomain(String url)
    {
        try
        {
            NamingEnumeration records=dirContext.getAttributes(url,new String[]{"mx"}).getAll();
            
            String[] address;
            String[] tmpMx;
            MX[] tmpMxArray;
            MX tmp;

            if(records.hasMore())
            {
                url=records.next().toString();
                url=url.substring(url.indexOf(": ")+2);
                address=url.split(",");
                tmpMxArray=new MX[address.length];

                for(int k=0;k<address.length;k++)
                {
                    tmpMx=address[k].trim().split(" ");
                    tmpMxArray[k]=new MX(Integer.parseInt(tmpMx[0]),tmpMx[1]);
                }
                
                for(int n=1;n<tmpMxArray.length;n++)
                {
                    for(int m=n;m>0;m--)
                    {
                        if(tmpMxArray[m-1].pri>tmpMxArray[m].pri)
                        {
                            tmp=tmpMxArray[m-1];
                            tmpMxArray[m-1]=tmpMxArray[m];
                            tmpMxArray[m]=tmp;
                        }
                    }
                }
                
                for(int k=0;k<tmpMxArray.length;k++)
                {
                    address[k]=tmpMxArray[k].address;
                }
                
                return address;
            }//分析mx记录

            records=dirContext.getAttributes(url,new String[]{"a"}).getAll();

            if(records.hasMore())
            {
                url=records.next().toString();
                url=url.substring(url.indexOf(": ")+2).replace(" ","");
                address=url.split(",");
                
                return address;
            }//分析a记录
            
            return new String[]{url};
        }
        catch(NamingException e)
        {
            log("错误: 域名\""+url+"\"无法解析");
            return null;
        }
    }
    
    /**
     * 获得响应码。
     * @param in 输入流
     * @return 响应码
     * @throws IOException 如果发生 I/O 错误。
     */
    private int response(InputStream in) throws IOException
    {
        byte[] buffer=new byte[1024];
        int k=in.read(buffer);
        
        if(k==-1)
        {
            return -1;
        }
        
        String response=new String(buffer,0,k).trim();
        log("响应: "+response);
        return Integer.parseInt(response.substring(0,3));
    }
    
    /**
     * 输出字符串。
     * @param str 字符串
     * @param out 输出流
     * @throws IOException 如果发生 I/O 错误。
     */
    private void sendString(String str,OutputStream out) throws IOException
    {
        log("发送: "+str);

        if(str==null)
        {
            str="";
        }
        
        out.write(str.getBytes());
        out.flush();
    }
    
    /**
     * 写日志。
     * @param info 信息
     */
    private void log(String info)
    {
        for(int n=0,m=logManager.size();n<m;n++)
        {
            logManager.get(n).output(info);
        }
    }

    /**
     * 输出一个换行符。
     * @param out 输出流
     * @throws IOException 如果发生 I/O 错误。
     */
    private static void sendNewline(OutputStream out) throws IOException
    {
        out.write('\r');
        out.write('\n');
        out.flush();
    }
    
    /**
     * 获得字符串的Base64加密形式。
     * @param str 字符串
     * @return 加密后的字符串
     */
    private static String getBase64String(String str)
    {
        if(str==null||str.length()==0)
        {
            return "";
        }
        
        StringBuffer tmpStr=new StringBuffer();
        byte[] bytes=str.getBytes();
        
        for(int k=0;k<bytes.length;)
        {
            if(k!=0)
            {
                tmpStr.append(' ');
            }
            
            tmpStr.append("=?");
            tmpStr.append(CHARSET);
            tmpStr.append("?B?");
            tmpStr.append(Base64.encode(bytes,k,Math.min(bytes.length-k,30)));
            tmpStr.append("?=");
            
            k+=30;
            
            if(k<bytes.length)
            {
                tmpStr.append('\r');
                tmpStr.append('\n');
            }
        }

        return tmpStr.toString();
    }
    
    /**
     * 分析邮箱域名。
     * @param address E-Mail地址
     * @return 邮箱域名
     */
    private static String parseUrl(String address)
    {
        return address.substring(address.lastIndexOf('@')+1);
    }
    
    /**
     * MX记录。
     */
    private class MX
    {
        final int pri;
        final String address;
        
        MX(int pri,String host)
        {
            this.pri=pri;
            this.address=host;
        }
    }
}

测试类

import java.io.File;

import org.gameeden.mail.SmtpMailSender;
import org.gameeden.util.LogManager;

/**
 * 测试类。
 */
public class TestSmtpMail
{
    public static void main(String[] args)
    {
        SmtpMailSender sms=SmtpMailSender.createSmtpMailSender("\"Black Fox\"<[e-mail]>");
    //    SmtpMailSender sms=SmtpMailSender.createESmtpMailSender("smtp.163.com","\"Object\"<[e-mail]>","java.lang.object","******");
        
        sms.addLogManager(new LogPrinter());//添加日志管理器
        
        if(sms.sendTextMail("\"Sol\"<[e-mail]>","STMP邮件测试","这是一封测试邮件。",new File[]{new File("java.gif")})==SmtpMailSender.SUCCESSFUL)
        {
            System.out.println("邮件发送成功。");
        }
        else
        {
            System.out.println("邮件发送失败。");
        }
    }
}

/**
 * 一个简单的日志管理器。
 */
class LogPrinter implements LogManager
{
    public void output(String info)
    {
        System.out.println(info);//将日志打印到控制台
    }
}

测试日志

状态: 创建邮件接收服务器列表
连接: 主机:"mx0.qq.com." 端口:"25"
响应: 220 mx7.qq.com ESMTP QQ Mail Server
发送: HELO gameeden.org
响应: 250 mx7.qq.com
发送: MAIL FROM: <[e-mail]>
响应: 250 Ok
发送: RCPT TO: <[e-mail]>
响应: 250 Ok
发送: DATA
响应: 354 End data with .
发送: From: =?GBK?B?QmxhY2sgRm94?= <[e-mail]>
发送: To: =?GBK?B?U29s?= <[e-mail]>
发送: Subject: =?GBK?B?U1RNUNPKvP6y4srU?=
发送: Date: Thu, 25 Oct 2007 10:42:13 +0800 (CST)
发送: MIME-Version: 1.0
发送: Content-Type: multipart/mixed; BOUNDARY="Boundary-=_hMbeqwnGNoWeLsRMeKTIPeofyStu"
发送: Content-Transfer-Encoding: base64
发送: X-Priority: 3
发送: X-Mailer: BlackFox Mail[Copyright(C) 2007 Sol]
发送:
发送: --Boundary-=_hMbeqwnGNoWeLsRMeKTIPeofyStu
发送: Content-Type: text/plain; charset="GBK"
发送: Content-Transfer-Encoding: base64
发送:
发送: 1eLKx9K7t+Ky4srU08q8/qGj
发送: --Boundary-=_hMbeqwnGNoWeLsRMeKTIPeofyStu
发送: Content-Type: image/gif; name="=?GBK?B?amF2YS5naWY=?="
发送: Content-Transfer-Encoding: base64
发送: Content-Disposition: attachment; filename="=?GBK?B?amF2YS5naWY=?="
发送:
发送: R0lGODlhOQA9AEQAACH/C05FVFNDQVBFMi4wAwEAAAAh+QQAyAAAACwAAAAAOQA9AKT///+Z
发送: mcz/zMzu7u5mZpn/mZm7u7vMzMzd3d3/mczMZpnMZmbMM2aZZpkzM5nMmcz/zP+IiIj/ZpnM
发送: MzNmM5nMzP+qqqrMADPMmZmZZmYAAAAAAAAAAAAAAAAAAAAAAAAF/yAgjmRpnmiqrmzrvnAs
发送: z3Rtk0JRCMPtiwKJQgABQBISwa9WkPRMuSVroOMBhiqBUnoSLCZbwI6V4JoKjAUJUgCEUW+z
发送: pKAoSYDF1CBv3imeIlQiBYAne2ZuO20kCVuLKXFLdXUlj5Qpj1JjlyOLAmVWUJmSiSZlYj0J
发送: fCRqbpE0n64lA1utdCYLWwyvMwmpq7KxBRc8jwutCqM2i40lVrkLaAIMWNFAYFKnsYw9DLsD
发送: F62yAwrEXJaVYhMiC3U5nkPiS49jnQITRblU9G1JZkT2RiigBmBBoza0APgriEjQCAHJEjCY
发送: MFFBMgADdi1UiEhMl11eBrTaVW9QoSVRnP8xAMCAXA+DEO6kQ1RyRBKDQ7woPAmgGc1RIies
发送: u9eDE4kCwFAm01LgGEWMKwecOqGMi5YtEC5YbDXVRMKOJ6hBYFCFlxGwJxTkukPFJ9oWEhEY
发送: wECLh68TFQLoRcBFroEDgA0w4NtIy6ASevUScOCAgAEbAwzsHTEAAQYMD/4meJRyQIAGBCgQ
发送: AM3YQQAaARwfMPAXMAIErXgYyHBALgYLklMTCCDZc+jUp2UEeBCAgt4IBJKPTvy5gW7RAQZE
发送: CC4iNQACCA5Q4NniAPDafy3gZm3AgvPhu0RUOEBigAP2BAAgwD6jwgDvAfimDNQqI4/siT1Q
发送: 3WmeVVfDasQtxxv/YAdkYAAC0yiB3wN8jRAfANFhRF0NuWVWYQKn3JVCfgB4Z6ANedHnDAoD
发送: FELiAA2IEEGFNvAWwHSsMRgYcYmxN0IFfMHYIgE+3jCAcgdU9lptCLToZGWrFelZZSr60JsB
发送: uzHHXGtNmsCXXtyhdsADD4Q5AgLEPUbCjUVKYUBjjWmpZZKU5UajGQEkCZpyop2n1555vnUm
发送: aMbduBtriSmnZkee6WXAE1gmpyWgvN3ppqTcyYVcaZLq1aZXn7qwGwIb9lWqC8HllmdtLbL4
发送: 5BOAVJZbrC2Q+l10gPFoaAMRTDddA3su5gAFw0r6YAkVLMqCAcgJq5xyfjKnHKcETJdZMayr
发送: /UVDZJ2SqWUEwGap5bPiHvuDd1lymV22umr5l5k/QMlaZn81Ca+g+Oar774jhAAAIfkEABQA
发送: AAAsAAAAADkAKwCk////mZnMzMzM7u7u/8zMZmaZ3d3du7u7/5mZzJnM/8z/zDNmmWaZMzOZ
发送: ZjOZiIiIzGZmzMz//5nMzGaZmWZmzJmZ/2aZqqqqAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
发送: Bf8gII5kaZ5oqq5s675wLM90bd94rsfE7gOS364nzBGLtyPSplzOms6YYhCtQasuKnam3cIG
发送: Xa/rKi4pw+XmdKQom98jMnagJrXdoiY4jueTgnl9IncjCCMShHhHBIYiEIKBIghEBI+QjQAL
发送: IwtyWwhtCI0QmH0KmgOaABOkfZwAEEEIE5CShgYLBqgrEQG9Bj4GBwcCAhQCBhBEFim9vQUN
发送: DQUHNgMHviMDFcTGAgBXAwEMBQ4F4tANATQB0gLCxMcJAAqGA+0HwcQJzgUB1uDj69LJCKDP
发送: Qa8HBRKWC9csAMJx/AY8EChiHYACBgQ4QONCQMBjw9olOHBBX7NjIyJbdMPWoFsBAAYwzohQ
发送: 75oJVgAGZGwWD0CvnAIpyhC5jkGvkO9+jfBIUKmIlz6pgMNhjeC9gb88VrzBS2aWMAF+DWAg
发送: 4oHTGv0c9kNK7IDJXitFRBDLAEyBuCZCAAAh+QQAFAAAACwAAAAAOQArAKT///+Zmczu7u7/
发送: zMzMzMz/mZlmZpnd3d27u7vMM2b/mczMZmbMZpn/zP/MmczMMzP/ZpkzM5mZZplmM5nMzP/M
发送: ADOIiIgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAF/yAgjmRpnmiqrmzrvnAsz4BQMMsC
发送: KXR/NouEoiEaFBaMgc83qFQS0BxjaCsQl7LFoCHodgcKRhJQUGJh15SCBz67RYKr+Y29Cuhn
发送: gXmOp9lEBX0+CmYMgj0JIwuHMzeAgYwmYAWUhGYCD3cNiZEkCg8LBWuUEDhBiwAJfJEDCXco
发送: rQMMD4adIwOrJVoCCWUQr7YKwCWyAw+QZMORlCdTDzwkuYzKIhUPuVy2KQWuJ4TaJwUV1CLd
发送: 4J5QKL3n0aoQJrzI7Km48gCt9ueOuJ7X8yQL7vADZO6fiHf3zEBAZXAEJD0AFHBqOALaPQBp
发送: KIpooESAgwPkSlAIQPIAnQMIEMAQWPlRwIGMJ0iSNBAhggEEPgQgKDnCJQGVP1MICCDBwAQD
发送: RWtGCEAjwM2fQAmATAjgwEqpQB3MNBBg51CjTpnKCKB1AkkLBtJyJSpz69EAAiyIFeEUgAGr
发送: E0KuIBAW68qUKdsGkDqCAgESAiIcNlD17gwKAvgGMNnCp0wHdJkOpdvjp1akJKOupCxC8kcS
发送: jAHArTG3x06yCEi/mAyAL2cfIx276EKCtgAJIizIbrpTbsqrf7XKPFzY5O8uBpifCAEAIfkE
发送: ABQAAAAsAAAAADkAKwCk////mZnM/8zM/5mZ7u7uzMzMzDNm/5nMZmaZzGZm3d3dzGaZu7u7
发送: /2aZ/8z/zJnMmWaZMzOZzDMzzMz/ZjOZiIiIqqqqzAAzzJmZAAAAAAAAAAAAAAAAAAAAAAAA
发送: AAAABf8gII5kaZKHYBJn675wrMZ0bQPHre/lwP+6AQtIhDWGxaQpoYQJBgmDNBFNLA5IErN5
发送: OkgHs9KTmhsJGtwSwZAIOw6DuCB7SJTb6dHaJxJIGwdwUAthAE9+eSMGfIYSKlkiKSULjGkO
发送: WyJtCxILJ3MkBgIOiZIjcZ0ujANohU2lfYAuDqgABiwCha08uD1QugADZQe0ZX1Ko2qGugaK
发送: SJW8RZ+Qhj1lArQElWBKBw7LJGsjCUgNhcxNc9sAa5jAfAKYAhJaleiU1FojhH0XM2u0iZ5A
发送: wsSMwIJQAGZJKJbIzKRIcRDCW9TwRKVsmSTwOciwIigSbxxIGWIAjccTCS7/brrn7qRFgAn7
发送: qavn0oUVYEOQ1XwBzwfMnS/K5TAJNEYnUUSLvniXVGmLMg8wKJhmYkKAqwrSKGDAoEABCwUU
发送: KPhp4upVBBEiIGBAhAADrHoeeC0AoYALAgEgIKCAQG/aCAF+BFhbgOtcBQ9EEGig4HDXAg/O
发送: IgjwFu/ewYF3BIhM4WoFBKD7XoVgdvDeyQQqZBYxGACCxhSoxiiAOexjBpEtWCgddsQEu3oi
发送: 2EUAQMFrHhMI0A6QFUW5FY3NJgZwdV3m1TsKRxZN2evj5iKWPwDvmjULvEnebmZAvgZzALRZ
发送: F7F6vAaBLO8JQBBRoT0PygGoZthc2vFGwgRZ6XcfBQLAnRACACH5BAAUAAAALAAAAAA5ACsA
发送: pP/////MzJmZzO7u7v+ZmczMzMwzZmZmmf+ZzN3d3cxmmbu7u8xmZv/M/8wzM8yZzJlmmf9m
发送: mTMzmWYzmcwAM8zM/5lmZoiIiMyZmaqqqgAAAAAAAAAAAAAAAAAAAAAAAAX/ICCOZGmeQBAg
发送: Kuq+MBwwjsEoBIEHce+XAYOBdwoQfkgYwkF8NZNQEcEw6A2qUZ/R4KBQbIRG7JlFzRyEwIAq
发送: MiqwKET5RUCPAhFT2nWcn6ZwKWRtgyIMfiYIBiQNK4UpYiU5iCWLAFNeaI8pJWuUjDk1X0Sb
发送: DZGGcp9tNUF9bU4jBIeqhocBCiWnf1KWtAgMPGEmjw24gLQib5d5JoEkDAgKvci4AAPAJ7oi
发送: ijfIJNUACDppziRBV94kzIIpOGZs6SSunEVDiuXpqSIN5QFM/lVmPFGgj5K2ALrWDPAnxt+T
发送: IN7IiMNCQM4QERe/bSrTwpwCYLZm3TIxK2LBbwCw/yGIMGhdRGWSAOACOGheOm3hLgG4iPNk
发送: PCApJolwhvCnCxXTOsayafSVS3bmIuCLxwMB0XJTqQ7wubGpiAcDHiQIpMZEBQFoE9BKsGBB
发送: gbcFMFx5suYJWrQHJEg4sGDOgAVpRwxga+Fthkj+XA0QAOHAhAON9UoQkEUA3wJt4SZIwASj
发送: WwwG3BZ4gPeAAMCLHVumDEUA6QloLxyY/RgtBAiMZzs2PeACaxGWARxIUGBC1hcFVhdgO7rw
发送: ggwW0EZfPqJCARIDJFw/ACDB8CgVBiQXoPYSFnDgBo93DZzyYuBlMJOGfPcthrcJ9I0XS4I7
发送: AAFVvOcHYK4tUJ5O9LhAHikAycE3x1nf+YDOCAsOAIEIFxxYxmkC+JYZXPLdJcB11all4RUH
发送: kHhCCAA7
发送: --Boundary-=_hMbeqwnGNoWeLsRMeKTIPeofyStu--
发送: .
响应: 250 Ok: queued as
发送: QUIT
响应: 221 Bye
邮件发送成功。



备注

  使用动态IP或伪造域名发送的本地邮件可能会被邮件服务商列为垃圾邮件拒收。



参考资料

RFC2821
RFC2045

评论

7 楼 weipt 2012-05-08  

麻烦问一下，这个怎么在android下应用？

6 楼 weipt 2012-05-08  

非常好。十分感谢！

5 楼 taihe 2011-07-05  

在发送附件的时候，我尝试将54修改微128或者1024，收到的附件都无法读取。

4 楼 skyfine 2009-03-15  

非常感谢，学习中。。。。

3 楼 mengyang 2008-12-05  

好帖子啊。。。
我做项目时用到javamail，但是发现有些地方根本无法实现（比如发送进度），最后还是要用到最基本的socket发邮件，还是基础重要啊。。。

2 楼 hxsmile 2008-10-09  

谢谢共享。

1 楼 folie2006 2008-10-07  

不错，收藏起来