spring.mail.host=smtp.qq.com
spring.mail.port=587
spring.mail.username=your-email@qq.com
spring.mail.password=your-smtp-password
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true

<dependencies>
    <!-- Spring Boot Starter Web -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- Spring Boot Starter Mail -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-mail</artifactId>
    </dependency>
    <!-- Lombok (Optional, for reducing boilerplate code) -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
</dependencies>

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.stereotype.Service;
 
import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.util.UUID;
 
@Service
public class EmailService {
 
    @Autowired
    private JavaMailSender mailSender;
 
    private static final String VERIFICATION_EMAIL_TEMPLATE = "Hello,\n\n" +
            "Please click the following link to verify your email:\n" +
            "%s\n\n" +
            "Best regards,\n" +
            "Your Application";
 
    public String sendVerificationEmail(String email) throws MessagingException {
        String verificationCode = UUID.randomUUID().toString();
        String verificationUrl = "http://localhost:8080/verify-email?code=" + verificationCode;
 
        MimeMessage message = mailSender.createMimeMessage();
        MimeMessageHelper helper = new MimeMessageHelper(message, "utf-8");
        helper.setTo(email);
        helper.setSubject("Email Verification");
        helper.setText(String.format(VERIFICATION_EMAIL_TEMPLATE, verificationUrl), true);
 
        mailSender.send(message);
 
        // Store the verification code in the database or cache, associated with the email
        // For simplicity, we'll just return the code here (In a real application, store it somewhere)
        return verificationCode; // In a real application, you should store this code and associate it with the user
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
 
import javax.mail.MessagingException;
import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.Map;
 
@RestController
@RequestMapping("/api")
public class EmailController {
 
    @Autowired
    private EmailService emailService;
 
    // In-memory storage for verification codes (for demo purposes only)
    private Map<String, String> verificationCodes = new HashMap<>();
 
    @PostMapping("/request-verification")
    public Map<String, String> requestVerification(@RequestParam String email) {
        Map<String, String> response = new HashMap<>();
        try {
            String verificationCode = emailService.sendVerificationEmail(email);
            verificationCodes.put(verificationCode, email); // Store the code temporarily
            response.put("message", "Verification email sent successfully!");
        } catch (MessagingException e) {
            response.put("error", "Failed to send verification email.");
        }
        return response;
    }
 
    @GetMapping("/verify-email")
    public Map<String, String> verifyEmail(@RequestParam String code) {
        Map<String, String> response = new HashMap<>();
        String email = verificationCodes.get(code);
        if (email != null) {
            // Email is verified, remove the code from the map and perform further actions
            verificationCodes.remove(code);
            response.put("message", "Email verified successfully!");
            // In a real application, update the user status in the database
        } else {
            response.put("error", "Invalid verification code.");
        }
        return response;
    }
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}