Java 对接 Office 365 邮箱全攻略：OAuth2 认证 + JDK8 兼容 + Spring Boot 集成（2025 版）

🚨 重要通知：微软强制 OAuth2，传统认证已失效！

2023 年 10 月起，Office 365 全面禁用用户名 + 密码认证，Java 开发者必须通过OAuth 2.0实现邮件发送。本文针对 CSDN 技术栈，提供从 Azure AD 配置到生产级代码的全流程方案，附 JDK 8 兼容实现和 Spring Boot 集成示例。

一、Office 365 对接核心流程（图示）

二、Azure AD 应用注册（分步教程）

1. 创建应用

   • 登录Azure 门户 → Azure AD → 应用注册 → 新建注册
   • 记录：Client ID、Client Secret、Tenant ID（租户域名或 ID）

2. 配置权限

   • 在API 权限中添加Microsoft Graph的Mail.Send权限（选择应用权限）
   • 点击授予管理员同意（需管理员账号操作）

3. 获取令牌端点

   plaintext

   令牌URL：https://login.microsoftonline.com/{tenantId}/oauth2/v2.0/token
   

三、Java 原生 API 实现（JDK 8 兼容）

1. 核心依赖（Maven）

xml

<dependency>
    <groupId>com.sun.mail</groupId>
    <artifactId>mail</artifactId>
    <version>1.6.2</version> <!-- JDK8唯一兼容版本 -->
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version> <!-- HTTP请求工具 -->
</dependency>

2. 完整代码示例

java

import javax.mail.*;
import javax.mail.internet.*;
import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;

public class Office365MailClient {
    private static final String TOKEN_URL = "https://login.microsoftonline.com/%s/oauth2/v2.0/token";
    private static final String SCOPE = "https://outlook.office365.com/.default";
    private final String tenantId, clientId, clientSecret, senderEmail;
    private final ConcurrentHashMap<String, String> tokenCache = new ConcurrentHashMap<>();

    public Office365MailClient(String tenantId, String clientId, String clientSecret, String senderEmail) {
        this.tenantId = tenantId;
        this.clientId = clientId;
        this.clientSecret = clientSecret;
        this.senderEmail = senderEmail;
    }

    public void sendHtmlEmail(String to, String subject, String htmlContent) throws Exception {
        String accessToken = getAccessToken();
        Properties props = getSmtpProperties(accessToken);
        
        Session session = Session.getInstance(props);
        MimeMessage msg = createMimeMessage(session, to, subject, htmlContent);
        
        try (Transport transport = session.getTransport("smtp")) {
            transport.connect(); // 自动触发XOAUTH2认证
            transport.sendMessage(msg, msg.getAllRecipients());
            System.out.println("发送成功，响应码：" + ((SMTPTransport) transport).getLastServerResponse());
        }
    }

    private Properties getSmtpProperties(String accessToken) {
        Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.office365.com");
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.auth.mechanisms", "XOAUTH2");
        
        // 注入OAuth2认证器
        props.put("mail.smtp.user", senderEmail);
        props.put("mail.smtp.password", accessToken);
        return props;
    }

    private MimeMessage createMimeMessage(Session session, String to, String subject, String htmlContent) 
            throws MessagingException {
        MimeMessage msg = new MimeMessage(session);
        msg.setFrom(new InternetAddress(senderEmail));
        msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));
        msg.setSubject(subject, "UTF-8");
        msg.setContent(htmlContent, "text/html; charset=utf-8");
        return msg;
    }

    // 令牌获取与缓存（简化实现）
    private String getAccessToken() throws Exception {
        // 实际需实现HTTP请求获取令牌，参考后文Spring Boot方案
        return "your_oauth2_token";
    }
}

四、Spring Boot 集成方案（生产级）

1. 依赖配置

xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-mail</artifactId>
    <exclusions>
        <exclusion>
            <groupId>com.sun.mail</groupId>
            <artifactId>javax.mail</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>com.sun.mail</groupId>
    <artifactId>javax.mail</artifactId>
    <version>1.6.2</version>
</dependency>

2. 配置文件（application.properties）

properties

spring.mail.host=smtp.office365.com
spring.mail.port=587
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.properties.mail.smtp.auth.mechanisms=XOAUTH2

office365.tenant-id=your_tenant_id
office365.client-id=your_client_id
office365.client-secret=your_client_secret
office365.sender-email=your_sender@example.com

3. 服务类实现

java

import org.springframework.beans.factory.annotation.Value;
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;

@Service
public class Office365MailService {
    private final JavaMailSender mailSender;
    private final String tenantId, clientId, clientSecret, senderEmail;
    private final Office365TokenProvider tokenProvider;

    public Office365MailService(JavaMailSender mailSender,
                               @Value("${office365.tenant-id}") String tenantId,
                               @Value("${office365.client-id}") String clientId,
                               @Value("${office365.client-secret}") String clientSecret,
                               @Value("${office365.sender-email}") String senderEmail) {
        this.mailSender = mailSender;
        this.tenantId = tenantId;
        this.clientId = clientId;
        this.clientSecret = clientSecret;
        this.senderEmail = senderEmail;
        this.tokenProvider = new Office365TokenProvider(tenantId, clientId, clientSecret);
    }

    public void sendEmail(String to, String subject, String htmlContent) throws MessagingException {
        MimeMessage message = mailSender.createMimeMessage();
        MimeMessageHelper helper = new MimeMessageHelper(message, true, "UTF-8");
        
        helper.setFrom(senderEmail);
        helper.setTo(to);
        helper.setSubject(subject);
        helper.setText(htmlContent, true); // 支持HTML
        
        // 注入令牌到邮件头（非必须，Spring自动处理认证）
        message.setHeader("Authorization", "Bearer " + tokenProvider.getAccessToken());
        
        mailSender.send(message);
    }
}

五、常见错误与解决方案

六、性能优化与安全实践

1. 令牌缓存
   使用ConcurrentHashMap或 Redis 缓存令牌，设置提前 5 分钟刷新：

   java

   private static final long TOKEN_EXPIRE = 3600; // 有效期1小时
   private static final long REFRESH_BUFFER = 300; // 提前5分钟刷新
   

2. 连接池配置
   在 Spring Boot 中配置连接池参数：

   properties

   spring.mail.properties.mail.smtp.connectionpool.size=20
   spring.mail.properties.mail.smtp.connectionpool.timeout=5000
   

3. 敏感信息管理

   • 禁止硬编码，使用环境变量或 Spring 配置中心
   • 通过azure-keyvault组件从 Key Vault 获取Client Secret

七、权威参考

1. 微软官方文档

   • Office 365 SMTP OAuth2 认证
   • Azure AD 应用权限配置

2. JavaMail 最佳实践

   • XOAUTH2 认证示例
   • JDK 8 兼容性指南

🌟 总结

本文提供了 Java 对接 Office 365 邮箱的完整解决方案，覆盖原生 API 和 Spring Boot 集成，特别针对 JDK 8 兼容性和 OAuth 2.0 认证做了深度优化。