JavaMailoauthrequiresfullmailscopeforsendingemailviagmail

使用OAuth2协议进行认证，并指定全范围(mail scope)来发送邮件。以下是示例代码：

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

public class SendEmail {

public static void main(String [] args) {

  String to = "recipient@gmail.com";  // 收件人邮箱地址
  String from = "sender@gmail.com";  // 发件人邮箱地址
  String host = "smtp.gmail.com";  // Gmail SMTP服务器地址
  String clientId = "your-client-id";  // 客户端ID
  String clientSecret = "your-client-secret";  // 客户端密钥
  String refreshToken = "your-refresh-token";  // 刷新令牌

  // 设置OAuth2认证
  Properties props = new Properties();
  props.put("mail.smtp.auth", "true");
  props.put("mail.smtp.starttls.enable", "true");  // 使用TLS加密
  props.put("mail.smtp.host", host);
  props.put("mail.smtp.port", "587");  // Gmail SMTP端口号
  props.put("mail.smtp.ssl.trust", host);
  props.put("mail.smtp.auth.mechanisms", "XOAUTH2");
  Session session = Session.getInstance(props,
     new javax.mail.Authenticator() {
        protected PasswordAuthentication getPasswordAuthentication() {
           return new PasswordAuthentication(from, null);
        }
        protected OAuth2Authenticator getOAuth2Authenticator() {
           return new OAuth2Authenticator(clientId, clientSecret, refreshToken);
        }
     });

  try {
     // 创建邮件消息
     MimeMessage message = new MimeMessage(session);
     message.setFrom(new InternetAddress(from));
     message.addRecipient(Message.RecipientType.TO,
                              new InternetAddress(to));
     message.setSubject("JavaMail OAuth2 test");
     message.setText("This is a test message sent via JavaMail OAuth2.");

     // 发送邮件
     Transport.send(message);

     System.out.println("Message sent successfully!");

  } catch (MessagingException e) {
     throw new RuntimeException(e);
  }

} }

class OAuth2Authenticator extends Authenticator {

private String clientId;
private String clientSecret;
private String refreshToken;

public