JavaMail实现发送超文本（html）格式邮件的方法

<%@ page contentType="text/html;charset=GBK" %><%@ page import="java.util.*"%><%@ page import="javax.mail.*" %><%@ page import="javax.mail.internet.*"%><%@ page import="javax.activation.*" %><%try{ request.setCharacterEncoding("GBK"); String from=request.getParameter("from"); String to=request.getParameter("to"); String subject=request.getParameter("subject"); String messageText=request.getParameter("content");  String password=request.getParameter("password"); //****如果是在Internet上发送电子邮件， 使用这段代码自动生成SMTP的主机名称********/ //int n =from.indexOf('@'); //int m=from.length() ; //String mailserver ="smtp."+from.substring(n+1,m);  String mailserver="mrlx";  //在局域网上发送电子邮件使用这句代码指定SMTP服务器  Properties prop =new Properties();  prop.put("mail.smtp.host",mailserver);  prop.put("mail.smtp.auth","true");  Session sess =Session.getInstance(prop);  sess.setDebug(true);  MimeMessage message=new MimeMessage(sess);  //给消息对象设置收件人、发件人、主题、发信时间  InternetAddress mail_from =new InternetAddress(from);  message.setFrom(mail_from);  InternetAddress mail_to =new InternetAddress(to);  message.setRecipient(Message.RecipientType.TO,mail_to);  message.setSubject(subject);  message.setSentDate(new Date());  Multipart mul=new MimeMultipart();  //新建一个MimeMultipart对象来存放多个BodyPart对象  BodyPart mdp=new MimeBodyPart();  //新建一个存放信件内容的BodyPart对象  mdp.setContent(messageText,"text/html;charset=GBK");  mul.addBodyPart(mdp);  //将含有信件内容的BodyPart加入到MimeMulitipart对象中  message.setContent(mul);  //把mul作为消息对象的内容  message.saveChanges();  Transport transport = sess.getTransport("smtp");  //以smtp方式登陆邮箱，第1个参数是发送邮件用的邮件服务器SMTP地址，  //第2个参数为用户名，第3个参数为密码  transport.connect(mailserver,from,password);  transport.sendMessage(message,message.getAllRecipients());  transport.close();  out.println("<script language='javascript'>alert('邮件已发送！');window.location.href='index.jsp';</script>");}catch(Exception e){ System.out.println("发送邮件产生的错误："+e.getMessage()); out.println("<script language='javascript'>alert('邮件发送失败！');window.location.href='index.jsp';</script>");}%>