极客学院团队出品 · 更新于 2018-11-28 11:00:43

JSP - 发送电子邮件

用一个 JSP 页面发送邮件虽然足够简单,但是开始你应该有 JavaMail API,而且在你的电脑上安装 Java Activation Framework (JAF)

下载和解压这些文件,对于所有的应用程序,在新建的顶层目录中你将可以发现许多 jar 文件。你需要在 CLASSPATH 中添加 mail.jaractivation.jar 文件。

发送一个简单的电子邮件

给出一个简单的例子,从你的机器上发送一个简单的邮件。假设你的本地主机连接到互联网,能够足以发送一封电子邮件。同时确保所有 jar 文件从 Java Email API 包到 JAF 包在 CLASSPATH 都是可用的。

<%@ page import="java.io.*,java.util.*,javax.mail.*"%>
<%@ page import="javax.mail.internet.*,javax.activation.*"%>
<%@ page import="javax.servlet.http.*,javax.servlet.*" %>
<%
   String result;
   // Recipient's email ID needs to be mentioned.
   String to = "abcd@gmail.com";

   // Sender's email ID needs to be mentioned
   String from = "mcmohd@gmail.com";

   // Assuming you are sending email from localhost
   String host = "localhost";

   // Get system properties object
   Properties properties = System.getProperties();

   // Setup mail server
   properties.setProperty("mail.smtp.host", host);

   // Get the default Session object.
   Session mailSession = Session.getDefaultInstance(properties);

   try{
      // Create a default MimeMessage object.
      MimeMessage message = new MimeMessage(mailSession);
      // Set From: header field of the header.
      message.setFrom(new InternetAddress(from));
      // Set To: header field of the header.
      message.addRecipient(Message.RecipientType.TO,
                               new InternetAddress(to));
      // Set Subject: header field
      message.setSubject("This is the Subject Line!");
      // Now set the actual message
      message.setText("This is actual message");
      // Send message
      Transport.send(message);
      result = "Sent message successfully....";
   }catch (MessagingException mex) {
      mex.printStackTrace();
      result = "Error: unable to send message....";
   }
%>
<html>
<head>
<title>Send Email using JSP</title>
</head>
<body>
<center>
<h1>Send Email using JSP</h1>
</center>
<p align="center">
<% 
   out.println("Result: " + result + "\n");
%>
</p>
</body>
</html>

现在将上面的代码放在 SendEmail.jsp 文件,并且使用 URL http://localhost:8080/SendEmail.jsp 来调用此 JSP,将电子邮件发送到给定的邮箱 ID 为 abcd@gmail.com 中,显示的响应结果如下所示。

Send Email using JSP

Result: Sent message successfully....

如果你想给多个收件人发送邮件,下面的方法可用于发送邮件给指定的多个邮箱 IDs:

void addRecipients(Message.RecipientType type, 
                   Address[] addresses)
throws MessagingException

下面是对参数的描述:

  • type: 可设置为 TO,CC 或者 BCC。其中,CC 表示 Carbon Copy,BCC 表示 Black Carbon Copy。例如,Message.RecipientType.TO

  • addresses: 它是邮箱 ID 的数组。你能使用 InternetAddress() 方法,同时指定邮箱 IDs。

发送 HTML 邮件

给出一个简单的例子,从你的机器上发送一个网页邮件。假设你的本地主机连接到互联网,能够足以发送一封电子邮件。同时确保所有 jar 文件从 Java Email API 包到 JAF 包在 CLASSPATH 都是可用的。

这个例子与之前给出的例子非常相似,除了在这个例子中我们使用 setContent() 方法设置第二个参数为“text/html”,用来指定网页内容包含在这个信息中。

使用这个例子,你可以发送与你喜欢的网页内容一样大的邮件。

<%@ page import="java.io.*,java.util.*,javax.mail.*"%>
<%@ page import="javax.mail.internet.*,javax.activation.*"%>
<%@ page import="javax.servlet.http.*,javax.servlet.*" %>
<%
   String result;
   // Recipient's email ID needs to be mentioned.
   String to = "abcd@gmail.com";

   // Sender's email ID needs to be mentioned
   String from = "mcmohd@gmail.com";

   // Assuming you are sending email from localhost
   String host = "localhost";

   // Get system properties object
   Properties properties = System.getProperties();

   // Setup mail server
   properties.setProperty("mail.smtp.host", host);

   // Get the default Session object.
   Session mailSession = Session.getDefaultInstance(properties);

   try{
      // Create a default MimeMessage object.
      MimeMessage message = new MimeMessage(mailSession);
      // Set From: header field of the header.
      message.setFrom(new InternetAddress(from));
      // Set To: header field of the header.
      message.addRecipient(Message.RecipientType.TO,
                               new InternetAddress(to));
      // Set Subject: header field
      message.setSubject("This is the Subject Line!");

      // Send the actual HTML message, as big as you like
      message.setContent("<h1>This is actual message</h1>",
                            "text/html" );
      // Send message
      Transport.send(message);
      result = "Sent message successfully....";
   }catch (MessagingException mex) {
      mex.printStackTrace();
      result = "Error: unable to send message....";
   }
%>
<html>
<head>
<title>Send HTML Email using JSP</title>
</head>
<body>
<center>
<h1>Send Email using JSP</h1>
</center>
<p align="center">
<% 
   out.println("Result: " + result + "\n");
%>
</p>
</body>
</html>

现在可以使用上述 JSP 发送网页信息给指定的邮箱 ID。

在电子邮件中发送附件:

给定一个例子,从你的机器上发送一个带附件的邮箱:

<%@ page import="java.io.*,java.util.*,javax.mail.*"%>
<%@ page import="javax.mail.internet.*,javax.activation.*"%>
<%@ page import="javax.servlet.http.*,javax.servlet.*" %>
<%
   String result;
   // Recipient's email ID needs to be mentioned.
   String to = "abcd@gmail.com";

   // Sender's email ID needs to be mentioned
   String from = "mcmohd@gmail.com";

   // Assuming you are sending email from localhost
   String host = "localhost";

   // Get system properties object
   Properties properties = System.getProperties();

   // Setup mail server
   properties.setProperty("mail.smtp.host", host);

   // Get the default Session object.
   Session mailSession = Session.getDefaultInstance(properties);

   try{
      // Create a default MimeMessage object.
      MimeMessage message = new MimeMessage(mailSession);

      // Set From: header field of the header.
      message.setFrom(new InternetAddress(from));

      // Set To: header field of the header.
      message.addRecipient(Message.RecipientType.TO,
                               new InternetAddress(to));

      // Set Subject: header field
      message.setSubject("This is the Subject Line!");

      // Create the message part 
      BodyPart messageBodyPart = new MimeBodyPart();

      // Fill the message
      messageBodyPart.setText("This is message body");

      // Create a multipar message
      Multipart multipart = new MimeMultipart();

      // Set text message part
      multipart.addBodyPart(messageBodyPart);

      // Part two is attachment
      messageBodyPart = new MimeBodyPart();
      String filename = "file.txt";
      DataSource source = new FileDataSource(filename);
      messageBodyPart.setDataHandler(new DataHandler(source));
      messageBodyPart.setFileName(filename);
      multipart.addBodyPart(messageBodyPart);

      // Send the complete message parts
      message.setContent(multipart );

      // Send message
      Transport.send(message);
      String title = "Send Email";
      result = "Sent message successfully....";
   }catch (MessagingException mex) {
      mex.printStackTrace();
      result = "Error: unable to send message....";
   }
%>
<html>
<head>
<title>Send Attachement Email using JSP</title>
</head>
<body>
<center>
<h1>Send Attachement Email using JSP</h1>
</center>
<p align="center">
<% 
   out.println("Result: " + result + "\n");
%>
</p>
</body>
</html>

现在可以运行上述 JSP 发送一个文件作为信息的附件给指定邮箱 ID。

用户身份验证部分

为了身份验证的目的,如果需要提供用户 ID 和密码给邮箱服务器,你可以设置这些属性如下:

props.setProperty("mail.user", "myuser");
 props.setProperty("mail.password", "mypwd");

邮件发送机制的设置和上述的解释一致。

用表单发送邮件

你可以使用网页表单接受邮件参数,然后你可以使用 request 对象获得如下的所有信息:

String to = request.getParameter("to");
String from = request.getParameter("from");
String subject = request.getParameter("subject");
String messageText = request.getParameter("body");

一旦你有所有信息,你可以使用以上提到的代码发送邮件。

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