java 发送qq 纯文字邮件

package org.zhiyi.config;

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

import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import java.util.Properties;
import java.util.regex.Pattern;

@Component
public class Email {

    @Value("${email.stmp}")
    String stmp;
    @Value("${email.account}")
    String username;
    @Value("${email.pwd}")
    String password;

    Session session;

    private void createSession() {
        Properties prop = new Properties();
        prop.setProperty("mail.host","smtp.qq.com");
        prop.setProperty("mail.transport.protocol","smtp");
        prop.setProperty("mail.smtp.auth","true");

        session = Session.getInstance(prop, new Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });

        session.setDebug(true);

    }
//发送邮件
    public void send(String recipient, String subject, String content) throws MessagingException {
        createSession();
        if(!emailFormat(recipient)){
            throw new RuntimeException("email format error!");
        }
        MimeMessage msg = new MimeMessage(session);
        msg.setFrom(new InternetAddress(username));
        msg.setRecipient(Message.RecipientType.TO, new InternetAddress(recipient));
        msg.setSubject(subject, "utf-8");

        MimeBodyPart body = new MimeBodyPart();
        body.setContent(content, "text/html;charset=utf-8");

        MimeMultipart mul = new MimeMultipart();
        mul.addBodyPart(body);

        msg.setContent(mul);

        Transport.send(msg);
    }
//邮件模板
    public String mesTemplate(String title, String body) {
        StringBuilder sb = new StringBuilder();
        sb.append("<h1>" + title + "</h1>");
        sb.append("<div>" + body + "</div>");
        return sb.toString();
    }
//验证邮箱格式
    final static Pattern partern = Pattern.compile("[a-zA-Z0-9]+[\\.]{0,1}[a-zA-Z0-9]+@[a-zA-Z0-9]+\\.[a-zA-Z]+");
    public static boolean emailFormat(String email){
        return partern.matcher(email).matches();
    }

}

Email email = new Email(); 
String code = "1234";
email.send("1098628245@qq.com", "验证码", email.mesTemplate("验证码", "您的验证码为<h2>" + code + "</h2>，验证码有效期为五分钟！"));