Spring Boot 之通过 JavaMailSender 实现邮件发送功能

使用JavaMailSender实现普通文本邮件和HMTL邮件发送。

util 包下：MailClient.java

package com.nowcoder.community.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.stereotype.Component;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;


@Component
public class MailClient {

    private static final Logger logger = LoggerFactory.getLogger(MailClient.class);

    @Autowired
    private JavaMailSender mailSender;

    @Value("${spring.mail.username}")
    private String from;

    public void sendMail(String to, String subject, String content) {
        try {
            MimeMessage message = mailSender.createMimeMessage();
            MimeMessageHelper helper = new MimeMessageHelper(message);
            helper.setFrom(from);
            helper.setTo(to);
            helper.setSubject(subject);
            helper.setText(content, true);
            mailSender.send(helper.getMimeMessage());
        } catch (MessagingException e) {
            logger.error("Fail to send E-mail!" + e.getMessage());
        }
    }

}

① 注解@Component把普通 POJO 实例化到 Spring 容器中
② 需要注入JavaMailSender
③ from 的注解@Value表示发送方
④ 发送邮件由 JavaMailSender 完成。首先JavaMailSender 的实例 mailSender 通过调用 createMimeMessage() 方法创建MimeMessage 的实例 message，再将 message 装配到 MimeMessageHelper 中生成 MimeMessageHelper 的实例 helper ，通过 helper 设置邮件的发送方、发送对象、标题、正文内容等。最后通过 mailSender 实现邮件发送。

编写测试类MailTests.java测试发送不同类型邮件。

package com.nowcoder.community;

import com.nowcoder.community.util.MailClient;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.ContextConfiguration;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.Context;


@SpringBootTest
@ContextConfiguration(classes = CommunityApplication.class)
public class MailTests {

    @Autowired
    private MailClient mailClient;

    @Autowired
    private TemplateEngine templateEngine;

    @Test
    public void testTextMail() {
        mailClient.sendMail("xxx@sina.com", "TEST", "Welcome to Sina!");
    }

    @Test
    public void testHtmlMail() {
        Context context = new Context();
        context.setVariable("username", "Lebron Le");

        String content = templateEngine.process("/mail/demo", context);
        System.out.println(content);

        mailClient.sendMail("xxx@sina.com", "HTML", content);
    }

}

① 需要注入MailClient、TemplateEngine
@ 通过模板引擎生成 html 邮件
③ context.setVariable("username", "Lebron Le");用于动态替换 html 文件中的对应拼接符

templates/mail/demo.html

    
    


欢迎您，！

新浪邮箱需要打开“客户端授权码”、“POP3/SMTP”服务、“IMAP4服务/SMTP服务”，同时设置：
application.properties

# MailProperties
spring.mail.host=smtp.sina.com
spring.mail.port=465
spring.mail.username=xxx@sina.com
spring.mail.password=客户端授权码，不是登录邮箱的密码
spring.mail.protocol=smtps
spring.mail.default-encoding=UTF-8
spring.mail.properties.mail.smtp.ssl.enable=true
spring.mail.properties.mail.smtp.socketFactory.port=465
spring.mail.properties.mail.smtp.socketFactory.class=javax.net.ssl.SSLSocketFactory

① 发送了一封标题为 TEST，正文内容为 Welcome to Sina! 的普通文本邮件。
② 发送了一封标题为 HTML，正文内容为 欢迎您，Lebron Le！的 HTML 邮件。