java定时发送邮件springBoot

package com.example.demo.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSenderImpl;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;

import java.text.SimpleDateFormat;
import java.util.Date;

@Service
@EnableScheduling   // 2.开启定时任务
public class IndexService{
    @Autowired
    JavaMailSenderImpl mailSender;  //引入邮件发送

    @Scheduled(cron = "0/5 * * * * ?")  //每隔5秒发送一次邮件
    public void hello(){


        SimpleMailMessage mailMessage