一：条件 必须下载sun公司的JavaMail API包，地址为：http://java.sun.com/products/javamail/

我这里用的是1.2版本，将相关包(jar文件)加到CLASSPATH中

二：该程序非常简单，不需要我们考虑很多地层的东西，因为API都帮我们做好了这些事情，下面是一个简单的发邮件的Servlet：(对于熟悉的人来说，恐怕是再简单不过了的一个servlet)

import java.io.*;

import javax.servlet.*;

import javax.servlet.http.*;

import sun.net.smtp.*;

public class SendMailServlet extends HttpServlet {

public static String MAIL_FROM = "from";

public static String MAIL_TO = "to";

public static String MAIL_SUBJECT = "subject";

public static String MAIL_BODY = "body";

public static String MAIL_HOST = "mailhost";

public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException

{

resp.setContentType("text/html; charset=gb2312");

PrintWriter out = resp.getWriter();

out.println("<form method=POST action=\"" + req.getRequestURI() + "\">");

out.println("<table>");

out.println("<tr><td>send mail server:</td>");

out.println("<td><input type=text name=" + MAIL_HOST + " size=30></td></tr>");

out.println("<tr><td>from:</td>");

out.println("<td><input type=text name=" + MAIL_FROM + " size=30></td></tr>");

out.println("<tr><td>to:</td>");

out.println("<td><input type=text name=" + MAIL_TO + " size=30></td></tr>");

out.println("<tr><td>subject:</td>");

out.println("<td><input type=text name=" + MAIL_SUBJECT + " size=30></td></tr>");

out.println("<tr><td>text:</td>");

out.println("<td><textarea name=" + MAIL_BODY + " cols=40 rows=10></textarea></td></tr>");

out.println("</table><br>");

out.println("<input type=submit value=\"Send\">");

out.println("<input type=reset value=\"Reset\">");

out.println("</form>");

out.flush();

}

public void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException,IOException

{

resp.setContentType("text/html; charset=gb2312");

PrintWriter out = new PrintWriter(resp.getOutputStream());

String from = req.getParameter(MAIL_FROM);

String to = req.getParameter(MAIL_TO);

String subject = req.getParameter(MAIL_SUBJECT);

String body = req.getParameter(MAIL_BODY);

String mailhost = req.getParameter(MAIL_HOST);

try

{

SmtpClient mailer = new SmtpClient(mailhost);

mailer.from(from);

mailer.to(to);

PrintStream ps = mailer.startMessage();

ps.println("From: " + from);

ps.println("To: " + to);

ps.println("Subject: " + subject);

ps.println(body);

mailer.closeServer();

out.println("Success!");

}

catch (Exception ex)

{

out.println("An error about:" + ex.getMessage());

}

out.flush();

}

public void init(ServletConfig cfg) throws ServletException

{

super.init(cfg);

}

public void destroy()

{

super.destroy();

}

}