java 实现发送邮件功能
今天分享一篇 java 发送 QQ 邮件的功能
环境：
jdk 1.8 + springboot 2.6.3 + maven 3.9.6
邮件功能依赖：
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-mail</artifactId></dependency>配置：
spring.mail.protocol=smtp
spring.mail.port=587
# qq邮箱
spring.mail.host=smtp.qq.com
# 发件人邮箱
spring.mail.username=xxx@qq.com
# 这里替换为自己的发件人邮箱的授权码
spring.mail.password=xxx
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.properties.mail.smtp.starttls.required=true获取授权码：
登录 QQ 邮箱网页版 -> 设置 -> 账号
往下翻：找到下面这一块区域，如果没有开启服务的，直接开启服务即可 然后点击管理服务
然后点击生成授权码
注意：生成后需要记住，授权码只展示这一次，如果忘了，可以生成多个
发送简单邮件
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
public class Test1Controller {@Autowiredprivate JavaMailSender mailSender;@Value("${from.email:xxx@qq.com}")private String fromEmail;@Value("${to.email:xxx@qq.com}")private String toEmail;@GetMapping("test")public void test() {sendSimpleMail();}public void sendSimpleMail() {SimpleMailMessage message = new SimpleMailMessage();message.setFrom(fromEmail); // 发件人邮箱message.setTo(toEmail);message.setSubject("主题：简单邮件");message.setText("内容：简单的邮件内容");mailSender.send(message);}
}发送带附件的邮件
import lombok.SneakyThrows;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.FileSystemResource;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;import javax.mail.internet.MimeMessage;
import java.io.File;@RestController
public class Test1Controller {@Autowiredprivate JavaMailSender mailSender;@Value("${from.email:xxx@qq.com}")private String fromEmail;@Value("${to.email:xxx@qq.com}")private String toEmail;@GetMapping("test")public void test() {sendAttachmentsMail();}@SneakyThrowspublic void sendAttachmentsMail() {MimeMessage mimeMessage = mailSender.createMimeMessage();MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true);helper.setFrom(fromEmail);helper.setTo(toEmail);helper.setSubject("主题：有附件");helper.setText("内容：有附件的邮件");FileSystemResource file = new FileSystemResource(new File("C:\\Users\\11786\\Desktop\\blackground\\1.jpg"));// 这里可以上传多个文件，我这里就直接用一个文件了helper.addAttachment("file-1.jpg", file);helper.addAttachment("file-2.jpg", file);helper.addAttachment("file-2.jpg", file);mailSender.send(mimeMessage);}
}使用 freemarker 发送模板邮件
在 resources -> templates -> email 目录下创建模板文件 template.ftl
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head><title>邮件标题</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<h1 th:text="${username}">用户名</h1>
<p>这是一封模板邮件。</p>
</body>
</html>发送邮件代码：
import freemarker.template.Configuration;
import freemarker.template.Template;
import lombok.SneakyThrows;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;import javax.mail.internet.MimeMessage;
import java.io.StringWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;@RestController
public class Test1Controller {@Autowiredprivate JavaMailSender mailSender;@Autowiredprivate Configuration freemarkerConfig;@Value("${from.email:xxx@qq.com}")private String fromEmail;@Value("${to.email:xxx@qq.com}")private String toEmail;@GetMapping("test")public void test() {sendTemplateMail();}@SneakyThrowspublic void sendTemplateMail() {MimeMessage mimeMessage = mailSender.createMimeMessage();MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true);helper.setFrom(fromEmail);helper.setTo(toEmail);helper.setSubject("主题：模板邮件");// 创建数据模型Map<String, Object> model = new HashMap<>();model.put("username", "heyue");// 获取模板Template template = freemarkerConfig.getTemplate("email/template.ftl");// 渲染模板Writer out = new StringWriter();template.process(model, out);String htmlContent = out.toString();// 设置邮件内容helper.setText(htmlContent, true);// 发送邮件mailSender.send(mimeMessage);}
}使用 thymeleaf 发送模板邮件
需要先引入依赖：
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-thymeleaf</artifactId></dependency>配置：
# 指定模板文件位置
spring.thymeleaf.prefix=classpath:/templates/email/
# 模板文件类型
spring.thymeleaf.suffix=.html
spring.thymeleaf.mode=HTML5
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.servlet.content-type=text/html
spring.thymeleaf.template-resolver-order=1在 resources -> templates -> email 目录下创建模板文件 template.html
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head><title>邮件标题</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<h1 th:text="${username}">用户名</h1>
<p>这是一封模板邮件。</p>
</body>
</html>发送邮件代码：
import lombok.SneakyThrows;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ApplicationContext;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.Context;import javax.mail.internet.MimeMessage;
import java.io.StringWriter;@RestController
public class Test1Controller {@Autowiredprivate JavaMailSender mailSender;@Autowiredprivate ApplicationContext applicationContext;@Value("${from.email:xxx@qq.com}")private String fromEmail;@Value("${to.email:xxx@qq.com}")private String toEmail;@GetMapping("test")public void test() {sendTemplateMail();}@SneakyThrowspublic void sendTemplateMail() {MimeMessage mimeMessage = mailSender.createMimeMessage();MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true);helper.setFrom(fromEmail);helper.setTo(toEmail);helper.setSubject("主题：模板邮件");// 获取 Thymeleaf 模板引擎TemplateEngine templateEngine = applicationContext.getBean(TemplateEngine.class);// 创建上下文并设置变量Context context = new Context();context.setVariable("username", "heyue");// 渲染模板StringWriter writer = new StringWriter();templateEngine.process("template", context, writer);String htmlContent = writer.toString();// 设置邮件内容helper.setText(htmlContent, true);// 发送邮件mailSender.send(mimeMessage);}
}