解决在阿里云服务器上面使用25端口无法发送腾讯企业邮箱邮件

[09:37:22] (SystemUserSelfService.java:469) - com.sun.mail.util.MailConnectException: Couldn't connect to host, port: smtp.exmail.qq.com, 25; timeout -1    at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2118)
    at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:712)
    at javax.mail.Service.connect(Service.java:388)
    at javax.mail.Service.connect(Service.java:246)
    at javax.mail.Service.connect(Service.java:195)
    at javax.mail.Transport.send0(Transport.java:254)
    at javax.mail.Transport.send(Transport.java:124)
    at cn.edu.scnu.ncsdc.sso.cloud.api.service.MailApi.send(MailApi.java:110)
    at cn.edu.scnu.ncsdc.sso.cloud.bussiness.service.SystemUserSelfService.sendMessage2Email(SystemUserSelfService.java:465)
    at cn.edu.scnu.ncsdc.sso.cloud.bussiness.service.SystemUserManageService.sendRegCode(SystemUserManageService.java:173)
    at cn.edu.scnu.ncsdc.sso.cloud.controller.manage.ManageSelfCtrl.sendUserRegCode(ManageSelfCtrl.java:639)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at cn.edu.scnu.ncsdc.sso.cloud.controller.filter.UserFilter.doFilter(UserFilter.java:64)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:677)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1457)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

原因：

阿里云封禁25号端口

出于安全考虑，阿里云默认封禁TCP 25端口出方向的访问流量，即你无法在阿里云上的云服务器通过TCP 25端口连接外部地址。

TCP 25端口的出方向封禁可能影响您通过TCP 25 端口连接第三方邮件服务商的SMTP服务器对外部发送邮件。

如果您需要使用阿里云上的云服务器对外部发送邮件，建议您使用阿里云邮产品或者使用第三方邮件服务商提供的465端口。

如果存在特殊场景，您必须在云服务器上使用TCP 25端口进行对外连接，请在安全管控平台中提交25端口解封申请。

阿里云：投诉，无故封禁25端口 （2016-12-06）

阿里云：TCP 25端口解封申请 （2018-06-27）

解决方法

SMTP服务器：ssl://smtp.exmail.qq.com

import javax.mail.*;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMessage.RecipientType;
import java.security.Security;
import java.util.List;
import java.util.Properties;


public class MailApi extends Authenticator {
    // 发送邮件的props文件
    private Properties props = System.getProperties();
    // 发件人邮箱账号
    private String username;
    // 发件人邮箱密码
    private String password;
    // 邮箱session
    private Session session;
    // 发送网关
    private String smtp;
    //超时时间（单位：毫秒）
    private Long timeout = 20000L;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getSmtp() {
        return smtp;
    }

    public void setSmtp(String smtp) {
        this.smtp = smtp;
    }

    public Long getTimeout() {
        return timeout;
    }

    public void setTimeout(Long timeout) {
        this.timeout = timeout;
    }

    private boolean createSession() {
        if (session == null) {
            if (this.username != null && this.password != null && this.smtp != null) {
                Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());
                final String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";
                props.put("mail.smtp.auth", "true");
                props.put("mail.smtp.host", smtp);
                props.put("mail.smtp.connectiontimeout", timeout);
                props.put("mail.smtp.timeout", timeout);
                props.put("mail.smtp.socketFactory.class", SSL_FACTORY);
                props.put("mail.smtp.socketFactory.fallback", "false");
                props.put("mail.smtp.port", "465");
                props.put("mail.smtp.socketFactory.port", "465");

                session = Session.getInstance(props, this);
            }
        }
        if (session != null) {
            return true;
        } else {
            return false;
        }
    }

    @Override
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication(username, password);
    }

    /**
     * 发送邮件
     *
     * @param recipient 收件人邮箱地址
     * @param subject   邮件主题
     * @param content   邮件内容
     * @throws AddressException
     * @throws MessagingException
     */
    public void send(String recipient, String subject, Object content)
            throws AddressException, MessagingException {
        if (createSession()) {
            // 创建mime类型邮件
            final MimeMessage message = new MimeMessage(session);
            // 设置发信人
            message.setFrom(new InternetAddress(this.username));
            // 设置收件人
            message.setRecipient(RecipientType.TO, new InternetAddress(recipient));
            // 设置主题
            message.setSubject(subject);
            // 设置邮件内容
            message.setContent(content.toString(), "text/html;charset=utf-8");
            // 发送
            Transport.send(message);
        }
    }

    /**
     * 群发邮件
     *
     * @param recipients 收件人列表
     * @param subject    主题
     * @param content    内容
     * @throws AddressException
     * @throws MessagingException
     */
    public void send(List recipients, String subject, Object content)
            throws AddressException, MessagingException {
        if (createSession()) {
            // 创建mime类型邮件
            final MimeMessage message = new MimeMessage(session);
            // 设置发信人
            message.setFrom(new InternetAddress(this.username));
            // 设置收件人们
            final int num = recipients.size();
            InternetAddress[] addresses = new InternetAddress[num];
            for (int i = 0; i < num; i++) {
                addresses[i] = new InternetAddress(recipients.get(i));
            }
            message.setRecipients(RecipientType.TO, addresses);
            // 设置主题
            message.setSubject(subject);
            // 设置邮件内容
            message.setContent(content.toString(), "text/html;charset=utf-8");
            // 发送
            Transport.send(message);
        }
    }
}