Java可以通过使用JavaMail API实现定期发送邮件的功能。下面是一个简单的示例代码：
import java.util.*;import javax.mail.*;import javax.mail.internet.*;public class EmailScheduler { private Timer timer; public EmailScheduler() { timer = new Timer(); } public void scheduleEmail(String recipient, String subject, String message, Date date) { timer.schedule(new TimerTask() { @Override public void run() { // 发送邮件 sendEmail(recipient, subject, message); } }, date); } private void sendEmail(String recipient, String subject, String message) { String sender = "your-email@example.com"; // 发送者邮箱 String password = "your-password"; // 发送者邮箱密码 Properties props = new Properties(); props.setProperty("mail.smtp.host", "smtp.example.com"); // SMTP服务器地址 props.setProperty("mail.smtp.auth", "true"); Session session = Session.getInstance(props, new Authenticator() { @Override protected PasswordAuthentication getPasswordAuthentication() { return new PasswordAuthentication(sender, password); } }); try { // 创建邮件消息 MimeMessage mimeMessage = new MimeMessage(session); mimeMessage.setFrom(new InternetAddress(sender)); mimeMessage.addRecipient(Message.RecipientType.TO, new InternetAddress(recipient)); mimeMessage.setSubject(subject); mimeMessage.setText(message); // 发送邮件 Transport.send(mimeMessage); System.out.println("邮件已发送"); } catch (MessagingException e) { e.printStackTrace(); } } public static void main(String[] args) { EmailScheduler scheduler = new EmailScheduler(); // 在指定日期时间发送邮件 Calendar calendar = Calendar.getInstance(); calendar.set(2022, Calendar.JANUARY, 1, 10, 0, 0); Date date = calendar.getTime(); scheduler.scheduleEmail("recipient@example.com", "定期邮件", "这是一封定期发送的邮件", date); }}上述示例代码使用了java.util.Timer类来定时发送邮件。scheduleEmail方法可以指定要发送邮件的收件人、主题、内容以及发送的日期时间。通过sendEmail方法使用JavaMail API发送邮件。
请注意替换代码中的sender、password和smtp.example.com等信息为你自己的实际邮箱信息和SMTP服务器地址。
