使用 Spring 配置邮件服务器

在现代的企业应用开发中，邮件发送是一个常见的需求。Spring 提供了强大的邮件支持，使得配置和发送邮件变得非常简单。本文将介绍如何在 Spring 应用中配置邮件服务器并发送电子邮件。

1. 引入 Spring 邮件依赖

首先，在项目的 pom.xml 文件中添加 Spring 邮件依赖：

<dependencies>
    <!-- Spring 邮件依赖 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-mail</artifactId>
    </dependency>
</dependencies>

2. 配置邮件服务器

在 application.properties 文件中添加邮件服务器的配置：

spring.mail.host=smtp.example.com
spring.mail.port=587
spring.mail.username=your-email@example.com
spring.mail.password=your-email-password
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.default-encoding=UTF-8

3. 创建邮件发送服务

创建一个 EmailService 类，用于封装邮件发送的逻辑：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.stereotype.Service;

@Service
public class EmailService {

    @Autowired
    private JavaMailSender mailSender;

    public void sendSimpleEmail(String to, String subject, String text) {
        SimpleMailMessage message = new SimpleMailMessage();
        message.setFrom("your-email@example.com");
        message.setTo(to);
        message.setSubject(subject);
        message.setText(text);
        mailSender.send(message);
    }
}

4. 使用邮件发送服务

在需要发送邮件的地方，注入 EmailService 并调用其方法：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class EmailController {

    @Autowired
    private EmailService emailService;

    @GetMapping("/send-email")
    public String sendEmail(@RequestParam String to, @RequestParam String subject, @RequestParam String text) {
        emailService.sendSimpleEmail(to, subject, text);
        return "Email sent successfully!";
    }
}

5. 发送 HTML 格式的邮件

如果需要发送 HTML 格式的邮件，可以修改 EmailService，使用 MimeMessage：

import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.mail.javamail.MimeMessagePreparator;

import javax.mail.internet.MimeMessage;

public void sendHtmlEmail(String to, String subject, String htmlContent) {
    MimeMessagePreparator messagePreparator = new MimeMessagePreparator() {
        @Override
        public void prepare(MimeMessage mimeMessage) throws Exception {
            MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage, true);
            messageHelper.setFrom("your-email@example.com");
            messageHelper.setTo(to);
            messageHelper.setSubject(subject);
            messageHelper.setText(htmlContent, true);
        }
    };
    mailSender.send(messagePreparator);
}

6. 测试邮件发送功能

编写测试代码来验证邮件发送功能：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

@Component
public class EmailTestRunner implements CommandLineRunner {

    @Autowired
    private EmailService emailService;

    @Override
    public void run(String... args) throws Exception {
        emailService.sendSimpleEmail("recipient@example.com", "Test Email", "This is a test email.");
        emailService.sendHtmlEmail("recipient@example.com", "Test HTML Email", "<h1>This is a test HTML email.</h1>");
    }
}