使用Servlet发送电子邮件

使用JavaMail实现收发电子邮件功能一文中介绍了如何安装JavaMail，使用JavaMail实现简单的邮件收发功能。本文介绍如何使用Servlet发送电子邮件。由于如何使用JavaMail已经在上文中有所介绍，因此本文将不做过多的原理介绍。

用Servlet实现邮件发送非常简单，我们只是需要构建一个jsp文件，提供给用户提交邮件信息的表单。
使用Servlet发送电子邮件

<%@ page contentType="text/Html;charset=gb2312"%>
<html>
<head>
  <title>Welcome</title>
</head>
<body>
  <center>
<p>Welcome</p>
<form name="form1" method="post" action="maildo">
    <p>收件人：
      <input type="text" name="send">
    </p>
    <p>主题：
      <input type="text" name="subject">
    </p>
    <p>内容：
      <textarea name="content"></textarea>
    </p>
    <p>
      <input type="submit" name="Submit" value="send">
    </p>
</form>
<p> </p>
</center>
</body>
</html>

浏览器收集到用户输入的信息后传递给Servlet来处理，Servlet通过request.getParameter()方法得到相关的数据后，通过JavaMail提供的API发送电子邮件。

package com.j2medev.servletmail;

import java.io.IOException;
import java.util.Properties;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.util.*;
import java.net.*;

public class MailServlet extends HttpServlet
{
private static String host;

private static String from;

    public void init(ServletConfig config) throws ServletException
    {
        super.init(config);
        host = config.getInitParameter("host");
        from = config.getInitParameter("from");
        System.out.println(host + from);
    }

    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException
    {

doPost(request, response);
}

    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException
    {

        String send = request.getParameter("send");
        String subject = request.getParameter("subject");
        String content = request.getParameter("content");

        try
        {
            Properties props = System.getProperties();
            // Setup mail server
            props.put("mail.smtp.host", host);
            // Get session
            Session session = Session.getDefaultInstance(props, null);
            // Define message
            MimeMessage message = new MimeMessage(session);
            // Set the from address
            message.setFrom(new InternetAddress(from));
            // Set the to address
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(
                    send));
            // Set the subject
            message.setSubject(subject);
            // Set the content
            message.setText(content);
            // Send message
            Transport.send(message);
        } catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}

接下来我们编辑web.XML文件，注意在init-param中写上host和from的参数，以便Servlet初始化的时候可以读取。
<?xml version="1.0" ?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
<servlet>
  <servlet-name>ServletMail</servlet-name>
  <servlet-class>com.j2medev.servletmail.MailServlet</servlet-class>
  <init-param>
   <param-name>host</param-name>
   <param-value>smtp.263.net</param-value>
     </init-param>
     <init-param>
     <param-name>from</param-name>
     <param-value>eric.zhan@263.net</param-value>
     </init-param>
</servlet>

<servlet-mapping>
  <servlet-name>ServletMail</servlet-name>
  <url-pattern>/maildo</url-pattern>
</servlet-mapping>
<welcome-file-list>
  <welcome-file>index.jsp</welcome-file>
</welcome-file-list>

<error-page>
<error-code>404</error-code>
<location>/error.jsp</location>
</error-page>

</web-app>
由于我们需要用到JavaMail和JAF的支持，因此我们需要把相关的包放到YOURAPP/WEB_INF/lib下。在浏览器输入http://localhost:8080/yourapp/index.jsp 发送电子邮件。

（出处：）