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📜  Java-发送电子邮件

📅  最后修改于: 2020-12-21 01:53:01             🧑  作者: Mango

使用Java应用程序发送电子邮件非常简单，但是从一开始，您应该在计算机上安装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。假定您的本地主机已连接到Internet，并且足以发送电子邮件。

例

// File Name SendEmail.java

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

public class SendEmail {

   public static void main(String [] args) {    
      // 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);

      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);
         System.out.println("Sent message successfully....");
      } catch (MessagingException mex) {
         mex.printStackTrace();
      }
   }
}

编译并运行该程序以发送简单的电子邮件-

输出

$ java SendEmail
Sent message successfully....

如果要将电子邮件发送给多个收件人，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。此处假定您的本地主机已连接到Internet，并且足以发送电子邮件。

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。

例

// File Name SendHTMLEmail.java

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

public class SendHTMLEmail {

   public static void main(String [] args) {
      // 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);

      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);
         System.out.println("Sent message successfully....");
      } catch (MessagingException mex) {
         mex.printStackTrace();
      }
   }
}

编译并运行该程序以发送HTML电子邮件-

输出

$ java SendHTMLEmail
Sent message successfully....

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。

例

// File Name SendFileEmail.java

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

public class SendFileEmail {

   public static void main(String [] args) {     
      // 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);

      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);
         System.out.println("Sent message successfully....");
      } catch (MessagingException mex) {
         mex.printStackTrace();
      }
   }
}

编译并运行该程序以发送HTML电子邮件-

输出

$ java SendFileEmail
Sent message successfully....

用户认证部分

如果需要出于身份验证目的而向电子邮件服务器提供用户标识和密码，则可以如下设置这些属性：

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

其余的电子邮件发送机制将保持如上所述。