JavaMail API详解（下）("JavaMail API深入解析（下篇）")

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ithorizon 6个月前 (10-19) 阅读数 37 #后端开发

JavaMail API深入解析（下篇）

一、JavaMail API 简介

在上一篇文章中，我们已经对JavaMail API进行了初步的介绍，包括其基本概念、核心类和接口。在本篇文章中，我们将深入探讨JavaMail API的高级特性，以及怎样在实际项目中应用这些特性。

二、邮件发送高级特性

JavaMail API提供了许多高级特性，如附件发送、邮件群发、邮件加密等。下面我们将一一介绍这些特性。

2.1 发送带附件的邮件

发送带附件的邮件需要使用MimeMultipart类来构建邮件内容。下面是一个发送带附件邮件的示例代码：


import javax.mail.*;
import javax.mail.internet.*;
import java.io.File;
import java.io.IOException;
public class SendEmailWithAttachment {
    public static void sendEmailWithAttachment(String host, String port, String username, String password, String recipient, String subject, String body, String filePath) throws MessagingException, IOException {
        Properties properties = System.getProperties();
        properties.setProperty("mail.smtp.host", host);
        properties.setProperty("mail.smtp.port", port);
        properties.setProperty("mail.smtp.auth", "true");
        Session session = Session.getInstance(properties, new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });
        MimeMessage message = new MimeMessage(session);
        message.setFrom(new InternetAddress(username));
        message.addRecipient(Message.RecipientType.TO, new InternetAddress(recipient));
        message.setSubject(subject);
        MimeBodyPart messageBodyPart = new MimeBodyPart();
        messageBodyPart.setText(body);
        MimeBodyPart attachmentBodyPart = new MimeBodyPart();
        DataSource source = new FileDataSource(filePath);
        attachmentBodyPart.setDataHandler(new DataHandler(source));
        attachmentBodyPart.setFileName(new File(filePath).getName());
        MimeMultipart multipart = new MimeMultipart();
        multipart.addBodyPart(messageBodyPart);
        multipart.addBodyPart(attachmentBodyPart);
        message.setContent(multipart);
        Transport.send(message);
        System.out.println("邮件发送顺利！");
    }
}

2.2 邮件群发

邮件群发可以通过添加多个收件人地址来实现。以下是一个邮件群发的示例代码：


import javax.mail.*;
import javax.mail.internet.*;
import java.util.Properties;
public class SendGroupEmail {
    public static void sendGroupEmail(String host, String port, String username, String password, String[] recipients, String subject, String body) throws MessagingException {
        Properties properties = new Properties();
        properties.put("mail.smtp.host", host);
        properties.put("mail.smtp.port", port);
        properties.put("mail.smtp.auth", "true");
        Session session = Session.getInstance(properties, new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });
        Message message = new MimeMessage(session);
        message.setFrom(new InternetAddress(username));
        InternetAddress[] toAddresses = new InternetAddress[recipients.length];
        for (int i = 0; i < recipients.length; i++) {
            toAddresses[i] = new InternetAddress(recipients[i]);
        }
        message.setRecipients(Message.RecipientType.TO, toAddresses);
        message.setSubject(subject);
        message.setText(body);
        Transport.send(message);
        System.out.println("邮件群发顺利！");
    }
}

2.3 邮件加密

邮件加密可以使用SSL或TLS来确保邮件内容的稳固性。以下是一个使用SSL发送邮件的示例代码：


import javax.mail.*;
import javax.mail.internet.*;
import java.util.Properties;
public class SendSecureEmail {
    public static void sendSecureEmail(String host, String port, String username, String password, String recipient, String subject, String body) throws MessagingException {
        Properties properties = new Properties();
        properties.put("mail.smtp.host", host);
        properties.put("mail.smtp.port", port);
        properties.put("mail.smtp.auth", "true");
        properties.put("mail.smtp.starttls.enable", "true");
        properties.put("mail.smtp.starttls.required", "true");
        Session session = Session.getInstance(properties, new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });
        Message message = new MimeMessage(session);
        message.setFrom(new InternetAddress(username));
        message.addRecipient(Message.RecipientType.TO, new InternetAddress(recipient));
        message.setSubject(subject);
        message.setText(body);
        Transport.send(message);
        System.out.println("加密邮件发送顺利！");
    }
}

三、邮件接收高级特性

JavaMail API同样赞成邮件接收的高级特性，如邮件搜索、邮件过滤等。

3.1 邮件搜索

邮件搜索可以使用SearchTerm类来实现。以下是一个邮件搜索的示例代码：


import javax.mail.*;
import javax.mail.search.*;
import java.util.Properties;
public class SearchEmail {
    public static void searchEmail(String host, String port, String username, String password, String searchQuery) throws MessagingException {
        Properties properties = new Properties();
        properties.put("mail.pop3.host", host);
        properties.put("mail.pop3.port", port);
        properties.put("mail.pop3.auth", "true");
        Session session = Session.getInstance(properties, new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });
        Store store = session.getStore("pop3");
        store.connect(host, username, password);
        Folder folder = store.getFolder("INBOX");
        folder.open(Folder.READ_ONLY);
        SearchTerm searchCondition = new SearchTerm() {
            public boolean match(Message message) {
                try {
                    return message.getSubject().contains(searchQuery);
                } catch (MessagingException e) {
                    e.printStackTrace();
                    return false;
                }
            }
        };
        Message[] messages = folder.search(searchCondition);
        for (Message message : messages) {
            System.out.println("Subject: " + message.getSubject());
        }
        folder.close(false);
        store.close();
    }
}

3.2 邮件过滤

邮件过滤可以使用Folder类的addMessageCountListener方法来实现。以下是一个邮件过滤的示例代码：


import javax.mail.*;
import javax.mail.event.*;
import java.util.Properties;
public class FilterEmail {
    public static void filterEmail(String host, String port, String username, String password) throws MessagingException {
        Properties properties = new Properties();
        properties.put("mail.pop3.host", host);
        properties.put("mail.pop3.port", port);
        properties.put("mail.pop3.auth", "true");
        Session session = Session.getInstance(properties, new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });
        Store store = session.getStore("pop3");
        store.connect(host, username, password);
        Folder folder = store.getFolder("INBOX");
        folder.open(Folder.READ_WRITE);
        folder.addMessageCountListener(new MessageCountAdapter() {
            public void messagesAdded(MessageCountEvent e) {
                Message[] messages = e.getMessages();
                for (Message message : messages) {
                    try {
                        if (message.getSubject().contains("urgent")) {
                            System.out.println("Received urgent email: " + message.getSubject());
                        }
                    } catch (MessagingException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        });
        // 等待邮件接收
        try {
            Thread.sleep(10000);
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        }
        folder.close(false);
        store.close();
    }
}