如何用JSP实现发邮件？

<%@ page contentType="text/html;charset=GBK" %><%@ page import=" javax.mail.*, javax.mail.internet.*, javax.activation.*,java.util.*" %> 
<html> 
<head> 
<TITLE>JSP meets JavaMail, what a sweet combo.</TITLE> 
</HEAD> 
<BODY> 
<% 
try{ 
Properties props = new Properties(); 
Session sendMailSession; 
Transport transport; sendMailSession = Session.getInstance(props, null); 
sendMailSession.setDebug(true);
props.put("mail.smtp.host", "mail.cwap.com"); 
//props.put("mail.transport.protocol",  "smtp");Message newMessage = new MimeMessage(sendMailSession); newMessage.setFrom(new InternetAddress("[email protected]")); 
newMessage.setRecipient(Message.RecipientType.TO, new InternetAddress("[email protected]")); 
newMessage.setSubject("subject"); 
newMessage.setSentDate(new Date()); 
newMessage.setText("nothing,just a test"); transport = sendMailSession.getTransport("smtp"); // here throws a exception~
transport.send(newMessage); 
transport.close();
%> 
<P>Your mail has been sent.</P> 
<% 
}catch(MessagingException m){ 
out.println(m.toString()); 
} 
%> 
</BODY> 
</HTML> 这个由问题，就是在家注释的地方跑出异常：javax.mail.NoSuchProviderException: smtp 　　关注！