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📜  Servlet-发送电子邮件

📅  最后修改于: 2020-11-12 05:45:22             🧑  作者: Mango

要使用Servlet发送电子邮件非常简单，但首先要在计算机上安装JavaMail API和Java激活框架(JAF) 。

下载并解压缩这些文件，在新创建的顶级目录中，您将找到两个应用程序的大量jar文件。您需要在CLASSPATH中添加mail.jar和activation.jar文件。

发送一个简单的电子邮件

这是从您的计算机发送简单电子邮件的示例。在此假定您的本地主机已连接到Internet，并且足以发送电子邮件。同时确保CLASSPATH中提供了Java Email API包和JAF包中的所有jar文件。

// File Name SendEmail.java
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;
 
public class SendEmail extends HttpServlet {

   public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      
      // Recipient's email ID needs to be mentioned.
      String to = "abcd@gmail.com";
 
      // Sender's email ID needs to be mentioned
      String from = "web@gmail.com";
 
      // Assuming you are sending email from localhost
      String host = "localhost";
 
      // Get system properties
      Properties properties = System.getProperties();
 
      // Setup mail server
      properties.setProperty("mail.smtp.host", host);
 
      // Get the default Session object.
      Session session = Session.getDefaultInstance(properties);
      
      // Set response content type
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();

      try {
         // Create a default MimeMessage object.
         MimeMessage message = new MimeMessage(session);
         
         // 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);
         String title = "Send Email";
         String res = "Sent message successfully....";
         String docType =
            ""-//w3c//dtd html 4.0 " + "transitional//en\">\n";
         
         out.println(docType +
            "\n" +
               "" + title + "\n" +
               "\n" +
                  "
" + title + "
\n" +
                  "
" + res + "
\n" +
               "
            "
         );
      } catch (MessagingException mex) {
         mex.printStackTrace();
      }
   }
}

现在让我们编译上面的servlet并在web.xml中创建以下条目

....
 
   SendEmail
   SendEmail

 

   SendEmail
   /SendEmail

....

现在使用URL http：// localhost：8080 / SendEmail调用此servlet，它将发送电子邮件到给定的电子邮件ID abcd@gmail.com ，并显示以下响应-

Send Email
Sent message successfully....

如果您想向多个收件人发送电子邮件，则可以使用以下方法指定多个电子邮件ID-

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

这是参数的描述-

  • 类型-将其设置为TO，CC或BCC。此处CC代表复本，BCC代表黑碳复本。示例Message.RecipientType.TO

  • 地址-这是电子邮件ID的数组。在指定电子邮件ID时，您将需要使用InternetAddress()方法。

发送HTML电子邮件

这是从您的计算机发送HTML电子邮件的示例。在此假定您的本地主机已连接到Internet，并且足以发送电子邮件。同时，确保CLASSPATH中提供了Java Email API包和JAF包中的所有jar文件。

此示例与上一个示例非常相似，除了这里我们使用setContent()方法设置第二个参数为“ text / html”的内容以指定HTML内容包含在消息中。

使用此示例，您可以发送尽可能多的HTML内容。

// File Name SendEmail.java
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;
 
public class SendEmail extends HttpServlet {
    
   public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      
      // Recipient's email ID needs to be mentioned.
      String to = "abcd@gmail.com";
 
      // Sender's email ID needs to be mentioned
      String from = "web@gmail.com";
 
      // Assuming you are sending email from localhost
      String host = "localhost";
 
      // Get system properties
      Properties properties = System.getProperties();
 
      // Setup mail server
      properties.setProperty("mail.smtp.host", host);
 
      // Get the default Session object.
      Session session = Session.getDefaultInstance(properties);
      
      // Set response content type
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();

      try {
         
         // Create a default MimeMessage object.
         MimeMessage message = new MimeMessage(session);
         
         // 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("
This is actual message
", "text/html" );
         
         // Send message
         Transport.send(message);
         String title = "Send Email";
         String res = "Sent message successfully....";
         String docType =
         ""-//w3c//dtd html 4.0 " + "transitional//en\">\n";
         
         out.println(docType +
            "\n" +
               "" + title + "\n" +
               "\n" +
                  "
" + title + "
\n" +
                  "
" + res + "
\n" +
               "
            "
         );
      } catch (MessagingException mex) {
         mex.printStackTrace();
      }
   }
}

编译并运行上述servlet，以在给定的电子邮件ID上发送HTML消息。

通过电子邮件发送附件

这是从您的机器发送带有附件的电子邮件的示例。在此假定您的本地主机已连接到Internet，并且足以发送电子邮件。

// File Name SendEmail.java
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;
 
public class SendEmail extends HttpServlet {

   public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
      
      // Recipient's email ID needs to be mentioned.
      String to = "abcd@gmail.com";
 
      // Sender's email ID needs to be mentioned
      String from = "web@gmail.com";
 
      // Assuming you are sending email from localhost
      String host = "localhost";

      // Get system properties
      Properties properties = System.getProperties();
 
      // Setup mail server
      properties.setProperty("mail.smtp.host", host);
 
      // Get the default Session object.
      Session session = Session.getDefaultInstance(properties);
      
      // Set response content type
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();

      try {
         // Create a default MimeMessage object.
         MimeMessage message = new MimeMessage(session);
 
         // 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";
         String res = "Sent message successfully....";
         String docType =
         ""-//w3c//dtd html 4.0 " + "transitional//en\">\n";
         
         out.println(docType +
            "\n" +
               "" + title + "\n" +
               "\n" +
                  "
" + title + "
\n" +
                  "
" + res + "
\n" +
               "
            "
         );
      } catch (MessagingException mex) {
         mex.printStackTrace();
      }
   }
}

在servlet上编译并运行，以发送文件作为附件以及给定电子邮件ID上的消息。

用户认证部分

如果需要提供用户ID和密码给电子邮件服务器以进行身份验证，则可以按以下方式设置这些属性-

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

电子邮件发送机制的其余部分将保持如上所述。