Spring Mail用QQ邮箱测试发送邮件失败

代码：

 public class SendMailController {

    //@Autowired
    private JavaMailSenderImpl mailSender;

    @RequestMapping(value ="/sendMail", method = RequestMethod.GET) 
    public void sendMail(HttpServletRequest request) throws MessagingException {
        mailSender = new JavaMailSenderImpl();
        mailSender.setHost("smtp.qq.com");  //设置邮件服务器
        mailSender.setUsername("XXXX@qq.com");
        mailSender.setPassword("**********");

        MimeMessage msg = mailSender.createMimeMessage();
        MimeMessageHelper msgHelper = new MimeMessageHelper(msg, true, "utf-8");

        msgHelper.setTo("YYYYYYYYY@qq.com");
        msgHelper.setFrom("XXXXXXX@qq.com");
        msgHelper.setSubject("测试发送带附件的邮件");
        msgHelper.setText("测试邮件");

        FileSystemResource file = new FileSystemResource(new File("D:/test.png"));
        msgHelper.addAttachment("test.png", file); //添加附件

        Properties prop = new Properties();
        prop.put("mail.smtp.auth", "true");
        prop.put("mail.smtp.timeout", "25000"); 
        mailSender.setJavaMailProperties(prop);

        mailSender.send(msg);

        System.out.println("邮件发送成功！");
    }
}

错误：
type Exception report
message Request processing failed; nested exception is org.springframework.mail.MailSendException: Mail server connection failed; nested exception is com.sun.mail.util.MailConnectException: Couldn't connect to host, port: smtp.qq.com, 25; timeout -1;
description The server encountered an internal error that prevented it from fulfilling this request.
exception
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.mail.MailSendException: Mail server connection failed; nested exception is com.sun.mail.util.MailConnectException: Couldn't connect to host, port: smtp.qq.com, 25; timeout -1;
nested exception is:
java.net.ConnectException: Connection timed out: connect. Failed messages: com.sun.mail.util.MailConnectException: Couldn't connect to host, port: smtp.qq.com, 25; timeout -1;
nested exception is:
java.net.ConnectException: Connection timed out: connect; message exceptions (1) are:
Failed message 1: com.sun.mail.util.MailConnectException: Couldn't connect to host, port: smtp.qq.com, 25; timeout -1;
nested exception is:
java.net.ConnectException: Connection timed out: connect
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:948)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)