Java使用mail.jar包发送邮件，支持多个收件人、多个抄送人、密送，可配多张图片。

package com.tools;

import java.io.BufferedReader;
import java.io.File;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.InetAddress;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Properties;


import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;


public class SendMail {


    //测试
    String emailUser="xxx@xxx.cn";
    String emailPassword="xxxx";


    InetAddress mailHost;
    InetAddress ourselves;
    BufferedReader in;
    PrintWriter out;
    String strmail;
    String initialID;
    String welcome;
    String sendOk;
    String recipientOk;
    String dataOk;
    String acceptedOk;


    /**
     * 发送邮件
     * 
     * @param to收件人，多个收件人","符号隔开
     * @param cc抄送，多个收件人","符号隔开
     * 
     * @param imagePath图片完整路径
     * @param attachments附件（这个先空到这）
     * 
     * @throws UnsupportedEncodingException 
     */
    public String sendEmailV2(String to,String subject,String content,String cc,String bcc,List imagePath, File[] attachments) throws AddressException, MessagingException, UnsupportedEncodingException{

    	String from = emailUser ;
    	
    	String mailhost = "smtp.exmail.qq.com";
    	boolean debug = false;
    	String username = emailUser;
    	String password = emailPassword; //
    	Properties props = System.getProperties();
    	props.put("mail.smtp.auth", "true");
    	
    	SMTPAuth auth = new SMTPAuth(username, password);
    	// could use Session.getTransport() and Transport.connect()
    	// assume we're using SMTP
    	if (mailhost != null)
    		props.put("mail.smtp.host", mailhost);

    	// Get a Session object
    	Session session = Session.getDefaultInstance(props, auth);
    	if (debug)
    		session.setDebug(true);

    	// construct the message
    	Message msg = new MimeMessage(session);
    	if (from != null)
    		msg.setFrom(new InternetAddress(from));
    	else
    		msg.setFrom();

    	//msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to, false));
    	//支持多个收件人
    	if(to.indexOf(",")!=-1){
    		String to2[]=to.split(",");
    		InternetAddress[] adr = new InternetAddress[to2.length];
    		for (int i = 0; i < adr.length; i++) {
    			adr[i] = new InternetAddress(to2[i]);
    		}
    		msg.setRecipients(Message.RecipientType.TO, adr);
    	}else{
    		msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to, false));
    	}
    	if (cc != null){
    		//msg.setRecipients(Message.RecipientType.CC, InternetAddress.parse(cc, false));
    		if(cc.indexOf(",")!=-1){
    			//多个
    			String cc2[]=cc.split(",");
    			InternetAddress[] adr = new InternetAddress[cc2.length];
    			for (int i = 0; i < cc2.length; i++) {
    				adr[i] = new InternetAddress(cc2[i]);
    			}
    			// Message的setRecipients方法支持群发。。注意:setRecipients方法是复数和点 到点不一样
    			msg.setRecipients(Message.RecipientType.CC, adr);
    		}else{
    			msg.setRecipients(Message.RecipientType.CC, InternetAddress.parse(cc, false));
    		}
    	}
    		
    	if (bcc != null)
    		msg.setRecipients(Message.RecipientType.BCC, InternetAddress.parse(bcc, false));

    	msg.setSubject(subject);

    	MimeBodyPart mbp1 = new MimeBodyPart();
    	String html = content;
    	mbp1.setContent(html, "text/html;charset=UTF-8");

    	MimeMultipart mp = new MimeMultipart("related");// alternative
    	mp.addBodyPart(mbp1);
    	
    	if(imagePath != null){
    		for (int i = 0; i < imagePath.size(); i++) {
    			
    			mp.addBodyPart(createImageMimeBodyPart(imagePath.get(i).toString() ));
    		}
    	}
    	
    	msg.setContent(mp);

    	msg.setSentDate(new Date());
    	Transport.send(msg);
    	
    	//System.out.println("****"+mp.getCount());
    	System.out.println("\n"+to+" 发送成功");
    	return "";
    }

    //添加内嵌图片
    private MimeBodyPart createImageMimeBodyPart(String imagePath) throws MessagingException, UnsupportedEncodingException{
        FileDataSource fds=new FileDataSource(imagePath);
        MimeBodyPart mbp=new MimeBodyPart();  
        DataHandler dh=new DataHandler(fds);
        mbp.setDataHandler(dh);  
        //设置对应的资源文件的唯一标识符，即 MIME 协议对于邮件的结构组织格式中的 Content-ID 头字段；
        mbp.setHeader("Content-ID", new File(imagePath.trim()).getName() );
        mbp.setFileName(fds.getName());  
        return mbp;
    }



    public static void main(String[] args){
    	
    	SendMail sd=new SendMail();
    	
    	
    	String to="xxx@xxx.cn";
    	String subject="xxxxxx";
    	
    	
    	List imagePath=new ArrayList();
    	imagePath.add("D:\\1.png");
    	imagePath.add("D:\\2.png");
    	
        String content="测试内容<img src=\"cid:1.png\"  /><br/><img src=\"cid:2.png\"  />";
    	
    	try {
    		sd.sendEmailV2(to, subject, content, null, null, imagePath, null);
    	} catch (AddressException e) {
    		// TODO Auto-generated catch block
    		e.printStackTrace();
    	} catch (UnsupportedEncodingException e) {
    		// TODO Auto-generated catch block
    		e.printStackTrace();
    	} catch (MessagingException e) {
    		// TODO Auto-generated catch block
    		e.printStackTrace();
    	}
    	
    }




}


class SMTPAuth extends javax.mail.Authenticator {
private String user, password;


    public SMTPAuth(String u, String p) {
    	user = u;
    	password = p;
    }
    public void getuserinfo(String getuser, String getpassword) {
    	user = getuser;
    	password = getpassword;
    }
    protected javax.mail.PasswordAuthentication getPasswordAuthentication() {
    	return new javax.mail.PasswordAuthentication(user, password);
    }



`}
`

mail.jar包下载链接: https://pan.baidu.com/s/1RD-wS5wSAx9IinYZHJDH_Q 提取码: tdcp