java发送邮件无法显示图片 图裂 的解决办法

package com.thinkgem.jeesite.common.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Date;
import java.util.Enumeration;   
import java.util.Properties;   
import java.util.Vector;   
  

import javax.activation.*;   
import javax.mail.Authenticator;   
import javax.mail.Message;   
import javax.mail.Multipart;   
import javax.mail.PasswordAuthentication;   
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;   


/**  
 * <p>  
 * Title: 使用javamail发送邮件  
 * </p>  
 */  
public class MailUtils {

    private static Logger logger = LoggerFactory.getLogger(MailUtils.class);
  
    String to = "";// 收件人   
    String toCC = "";//抄送
    String toBcc = "";//密送
    String from = "";// 发件人   
    String host = "";// smtp主机    
    String port = "";
    String username = "";   
    String password = "";   
    String filename = "";// 附件文件名   
    String subject = "";// 邮件主题   
    String content = "";// 邮件正文   
    String imagepath = "";// 图片路径
    Vector file = new Vector();// 附件文件集合


    public String getImagepath() {
        return imagepath;
    }

    public void setImagepath(String imagepath) {
        this.imagepath = imagepath;
    }
  
    /**  
     * <br>  
     * 方法说明：默认构造器 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    public MailUtils() {   
    }   
  
    /**  
     * <br>  
     * 方法说明：构造器，提供直接的参数传入 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    public MailUtils(String to, String from, String smtpServer,   
            String username, String password, String subject, String content) {   
        this.to = to;   
        this.from = from;   
        this.host = smtpServer;   
        this.username = username;   
        this.password = password;   
        this.subject = subject;   
        this.content = content;   
    }   
  
    public void setPort(String port){
        this.port = port;
    }
    
    /**  
     * <br>  
     * 方法说明：设置邮件服务器地址 <br>  
     * 输入参数：String host 邮件服务器地址名称 <br>  
     * 返回类型：  
     */  
    public void setHost(String host) {   
        this.host = host;   
    }   
  
    /**  
     * <br>  
     * 方法说明：设置登录服务器校验密码 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    public void setPassWord(String pwd) {   
        this.password = pwd;   
    }   
  
    /**  
     * <br>  
     * 方法说明：设置登录服务器校验用户 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    public void setUserName(String usn) {   
        this.username = usn;   
    }   
  
    /**  
     * <br>  
     * 方法说明：设置邮件发送目的邮箱 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    public void setTo(String to) {   
        this.to = to;   
    }   
    
    /**
     * 设置抄送者
     * 
     * */
    public void setToCC(String to){
        this.toCC = to;
    }
    
    public void setToBcc(String to){
        this.toBcc = to;
    }
  
    /**  
     * <br>  
     * 方法说明：设置邮件发送源邮箱 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    public void setFrom(String from) {   
        this.from = from;   
    }   
  
    /**  
     * <br>  
     * 方法说明：设置邮件主题 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    public void setSubject(String subject) {   
        this.subject = subject;   
    }   
  
    /**  
     * <br>  
     * 方法说明：设置邮件内容 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    public void setContent(String content) {   
        this.content = content;   
    }   
  
    /**  
     * <br>  
     * 方法说明：把主题转换为中文 <br>  
     * 输入参数：String strText <br>  
     * 返回类型：  
     */  
    public String transferChinese(String strText) {   
        try {   
            strText = MimeUtility.encodeText(new String(strText.getBytes("UTF-8"),   
                    "UTF-8"), "UTF-8", "B");   
        } catch (Exception e) {   
            e.printStackTrace();
        }   
        return strText;   
    }   
  
    /**  
     * <br>  
     * 方法说明：往附件组合中添加附件 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    public void attachfile(String fname) {   
        file.addElement(fname);   
    }   
  
    /**  
     * <br>  
     * 方法说明：发送邮件 <br>  
     * 输入参数： <br>  
     * 返回类型：boolean 成功为true，反之为false  
     */  
    public boolean sendMail() {
        logger.info("------开始发邮件------");
        // 构造mail session   
        Properties props = new Properties() ;   
        props.put("mail.smtp.host", host);   
        props.put("mail.smtp.auth", "true");
        if(port != "")
            props.put("mail.smtp.port", port);
        Session session = Session.getDefaultInstance(props,   
                new Authenticator() {   
                    public PasswordAuthentication getPasswordAuthentication() {   
                        return new PasswordAuthentication(username, password);   
                    }   
                });   
        //Session session = Session.getDefaultInstance(props);   
//      Session session = Session.getDefaultInstance(props, null);   
  
        try {   
            // 构造MimeMessage 并设定基本的值   
            MimeMessage msg = new MimeMessage(session);   
            //MimeMessage msg = new MimeMessage();   
            msg.setFrom(new InternetAddress(from));   
            
               
            //msg.addRecipients(Message.RecipientType.TO, address); //这个只能是给一个人发送email   
            //设置接收者
            if(!Empty2String(to))
                msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to)) ;
            //设置抄送者
            if(!Empty2String(toCC))
                msg.setRecipients(Message.RecipientType.CC, InternetAddress.parse(toCC)) ;
            //设置密送者
            if(!Empty2String(toBcc))
                msg.setRecipients(Message.RecipientType.BCC, InternetAddress.parse(toBcc)) ;
            
            subject = transferChinese(subject);   
            msg.setSubject(subject);   
           
            // 构造Multipart   
            Multipart mp = new MimeMultipart();   
  
            // 向Multipart添加正文   
            MimeBodyPart mbpContent = new MimeBodyPart();   
            mbpContent.setContent(content, "text/html;charset=gb2312");   
               
            // 向MimeMessage添加（Multipart代表正文）   
            mp.addBodyPart(mbpContent);   
  
            // 向Multipart添加附件   
            Enumeration efile = file.elements();   
            while (efile.hasMoreElements()) {   
  
                MimeBodyPart mbpFile = new MimeBodyPart();   
                filename = efile.nextElement().toString();   
                FileDataSource fds = new FileDataSource(filename);   
                mbpFile.setDataHandler(new DataHandler(fds));   
               //<SPAN style="COLOR: #ff0000">//这个方法可以解决附件乱码问题。</SPAN>      
                String filename= new String(fds.getName().getBytes(),"ISO-8859-1");   
  
                mbpFile.setFileName(filename);   
                // 向MimeMessage添加（Multipart代表附件）   
                mp.addBodyPart(mbpFile);   
  
            }   
  
            file.removeAllElements();   
            // 向Multipart添加MimeMessage   
            msg.setContent(mp);   
            msg.setSentDate(new Date());   
            msg.saveChanges() ;   
            // 发送邮件   
               
            Transport transport = session.getTransport("smtp");   
            transport.connect(host, username, password);   
            transport.sendMessage(msg, msg.getAllRecipients());   
            transport.close();   
        } catch (Exception mex) {   
            mex.printStackTrace();
            logger.info("---发邮件报错信息----"+mex.getMessage());
//          Exception ex = null;   
//          if ((ex = mex.getNextException()) != null) {   
//              ex.printStackTrace();   
//          }   
            return false;   
        }   
        return true;   
    }

    /***
     * 发送带有图片的邮件
     * @return
     */
    public boolean sendPicMail() {
        logger.info("------开始发邮件------");
        // 构造mail session
        Properties props = new Properties() ;
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.auth", "true");
        if(port != "")
            props.put("mail.smtp.port", port);
        Session session = Session.getDefaultInstance(props,
                new Authenticator() {
                    public PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(username, password);
                    }
                });
        //Session session = Session.getDefaultInstance(props);
//      Session session = Session.getDefaultInstance(props, null);

        try {
            // 构造MimeMessage 并设定基本的值
            MimeMessage msg = new MimeMessage(session);
            //MimeMessage msg = new MimeMessage();
            msg.setFrom(new InternetAddress(from));


            //msg.addRecipients(Message.RecipientType.TO, address); //这个只能是给一个人发送email
            //设置接收者
            if(!Empty2String(to))
                msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to)) ;
            //设置抄送者
            if(!Empty2String(toCC))
                msg.setRecipients(Message.RecipientType.CC, InternetAddress.parse(toCC)) ;
            //设置密送者
            if(!Empty2String(toBcc))
                msg.setRecipients(Message.RecipientType.BCC, InternetAddress.parse(toBcc)) ;

            subject = transferChinese(subject);
            msg.setSubject(subject);

            // 构造Multipart
            MimeMultipart mp = new MimeMultipart("related");

            // 向Multipart添加正文
            MimeBodyPart mbpContent = new MimeBodyPart();
            mbpContent.setContent(content, "text/html;charset=gb2312");

            // 向MimeMessage添加（Multipart代表正文）
            mp.addBodyPart(mbpContent);

            // second part (the image)
            MimeBodyPart imageBodyPart = new MimeBodyPart();
            DataSource imageds = new FileDataSource(imagepath);
            imageBodyPart.setDataHandler(new DataHandler(imageds));
            imageBodyPart.setHeader("Content-ID","<attach>");
            imageBodyPart.setHeader("Content-Type", "image/png");
            imageBodyPart.setDisposition(MimeBodyPart.INLINE);
            imageBodyPart.setFileName("attach.png");

            // add it
            mp.addBodyPart(imageBodyPart);

            // 向Multipart添加附件
            Enumeration efile = file.elements();
            while (efile.hasMoreElements()) {

                MimeBodyPart mbpFile = new MimeBodyPart();
                filename = efile.nextElement().toString();
                FileDataSource fds = new FileDataSource(filename);
                mbpFile.setDataHandler(new DataHandler(fds));
                //<SPAN style="COLOR: #ff0000">//这个方法可以解决附件乱码问题。</SPAN>
                String filename= new String(fds.getName().getBytes(),"ISO-8859-1");

                mbpFile.setFileName(filename);
                // 向MimeMessage添加（Multipart代表附件）
                mp.addBodyPart(mbpFile);

            }

            file.removeAllElements();
            // 向Multipart添加MimeMessage
            msg.setContent(mp);
            msg.setSentDate(new Date());
            msg.saveChanges() ;
            // 发送邮件

            Transport transport = session.getTransport("smtp");
            transport.connect(host, username, password);
            transport.sendMessage(msg, msg.getAllRecipients());
            transport.close();
        } catch (Exception mex) {
            mex.printStackTrace();
            logger.info("---发邮件报错信息----"+mex.getMessage());
//          Exception ex = null;
//          if ((ex = mex.getNextException()) != null) {
//              ex.printStackTrace();
//          }
            return false;
        }
        return true;
    }


    public static boolean Empty2String(String str){
        return str == null || "".equals(str) || "null".equals(str) || "NULL".equals(str);
    }


    /**  
     * <br>  
     * 方法说明：主方法，用于测试 <br>  
     * 输入参数： <br>  
     * 返回类型：  
     */  
    
    public static void main(String[] args) {   
        MailUtils sendmail = new MailUtils();  
           
        sendmail.setHost("smtp.cmge.com");   
        sendmail.setUserName("system.omss@cmge.com");
        sendmail.setFrom("system.omss@cmge.com");        
        sendmail.setPassWord("XXXXX");
        
        sendmail.setTo("lu.shiqin@cmge.com,system.omss@cmge.com");
        //sendmail.setToCC("");
          
        sendmail.setSubject("你好22，这是测ddddd试！");   
        sendmail.setContent("<h1>你好这是一个带多附件多人发送的的测试！~~~~~~~~~~~~~~~~~~~~~~~~~</h1>"+"<img src="cid:attach">");   

　　　　 sendmail.setImagepath(picpath);

        sendmail.sendPicMail()

        //sendmail.attachfile("F:\mac共享\受害用户名单20150119.csv");   
        //sendmail.attachfile("F:\mac共享\接听转接验证号码20150119.csv");           
       // logger.info(sendmail.sendMail());
    }   
}

 防止图裂：

要想正确显示邮件的图片内容，必须做到如下几点：
1. MimeMultipart的类型必须是“related”（new MimeMultipart(“related”)）；
2. 图片的显示方式必须为“INLINE”（Disposition=MimeBodyPart.INLINE）；
3. 必须明确指定“Content-Type”头信息（Content-Type=image/png）；
4. 图片名称与“Content-ID”绝不能为“image”（可能为关键字）；

参考帖子：

https://blog.csdn.net/yiifaa/article/details/78394230