java gmail邮箱发送邮件

### 使用Java通过Gmail SMTP发送邮件的解决方案 以下是基于提供的引用内容以及专业知识编写的示例代码，展示如何使用Java通过Gmail SMTP服务器发送电子邮件。 #### 配置JavaMail属性 为了成功连接到Gmail的SMTP服务器并发送邮件，需要正确设置`Properties`对象中的参数。这些参数包括主机名、端口号、身份验证标志以及其他必要的安全选项[^3]： ```java import java.util.Properties; import javax.mail.Message; import javax.mail.MessagingException; import javax.mail.Session; import javax.mail.Transport; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage; public class GmailEmailSender { private static final String SMTP_HOST = "smtp.gmail.com"; private static final int SMTP_PORT = 587; // Use port 587 for TLS or 465 for SSL private static final String USERNAME = "[email protected]"; // Replace with your Gmail address private static final String PASSWORD = "your-app-password"; // Replace with your app-specific password public static void sendEmail(String recipient, String subject, String content) { Properties properties = new Properties(); properties.put("mail.smtp.host", SMTP_HOST); properties.put("mail.smtp.port", Integer.toString(SMTP_PORT)); properties.put("mail.smtp.auth", "true"); properties.put("mail.smtp.starttls.enable", "true"); // Enable STARTTLS encryption Session session = Session.getInstance(properties, null); try { Message message = new MimeMessage(session); message.setFrom(new InternetAddress(USERNAME)); // Sender's email address message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(recipient, false)); // Recipient's email address message.setSubject(subject); // Subject of the email message.setText(content); // Content/body of the email Transport transport = session.getTransport("smtp"); transport.connect(SMTP_HOST, USERNAME, PASSWORD); // Authenticate using credentials transport.sendMessage(message, message.getAllRecipients()); // Send the email System.out.println("Email sent successfully."); transport.close(); } catch (MessagingException e) { e.printStackTrace(); } } public static void main(String[] args) { String recipient = "[email protected]"; // Replace with actual recipient's email String subject = "Test Email from Java"; String content = "This is a test email sent via Java and Gmail SMTP server."; sendEmail(recipient, subject, content); } } ``` #### 关键点说明 1. **SMTP Host 和 Port**: 上述代码中使用的SMTP主机名为`smtp.gmail.com`，端口为`587`（适用于TLS加密）。如果更倾向于SSL，则可以改用端口`465`。 2. **身份验证**: Google要求启用两步验证，并生成专用的应用程序密码来代替常规账户密码[^1]。 3. **异常处理**: `MessagingException`被用来捕获任何可能发生的错误，例如网络问题或认证失败等问题[^2]。 #### Spring框架集成方式 如果您正在开发Spring项目，可以通过注入`JavaMailSender`实例简化邮件发送逻辑[^5]。下面是一个简单的例子： ```java import org.springframework.beans.factory.annotation.Autowired; import org.springframework.mail.javamail.JavaMailSender; import org.springframework.mail.SimpleMailMessage; import org.springframework.stereotype.Service; @Service public class EmailService { @Autowired private JavaMailSender javaMailSender; public void sendSimpleMessage(String to, String subject, String text) { SimpleMailMessage message = new SimpleMailMessage(); message.setTo(to); message.setSubject(subject); message.setText(text); javaMailSender.send(message); } } // Configuration Class Example @Configuration public class MailConfig { @Bean public JavaMailSender getJavaMailSender() { JavaMailSenderImpl mailSender = new JavaMailSenderImpl(); mailSender.setHost("smtp.gmail.com"); mailSender.setPort(587); mailSender.setUsername("[email protected]"); mailSender.setPassword("your-app-password"); Properties props = mailSender.getJavaMailProperties(); props.put("mail.transport.protocol", "smtp"); props.put("mail.smtp.auth", "true"); props.put("mail.smtp.starttls.enable", "true"); return mailSender; } } ``` ---