spingboot 邮件模板发送；

 <!-- 邮件start -->
<dependency>
    <groupId>javax.mail</groupId>
    <artifactId>mail</artifactId>
    <version>1.4.7</version>
</dependency>
<!-- 邮件end -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-mail</artifactId>
</dependency>
<!--freemarker模板引擎-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-freemarker</artifactId>
</dependency>
<!--quartz定时-->
<dependency>
    <groupId>org.quartz-scheduler</groupId>
    <artifactId>quartz</artifactId>
    <version>2.2.1</version>
</dependency>
-------------------------------------------------------------------

# JavaMailSender 邮件发送的配置s
spring.mail.host=smtp.qq.com
spring.mail.username=98@qq.com
spring.mail.password=klfrwbbhd
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.properties.mail.smtp.starttls.required=true
# JavaMailSender 邮件发送的配置e
#每60执行一次
scheduled.cron=0/60 * * * * ?
#初次执行任务之前需要等待的时间(5秒)
scheduled.initialDelay=60000
#每次执行任务之后间隔多久再次执行该任务（60秒）执行频率
scheduled.fixedDelay=60000
#执行频率，每隔多少时间就启动任务，不管该任务是否启动完成
scheduled.fixedRate=60000
----------------------------------------------------------------

package com.manage.util;

import com.w3china.mingjing3.model.MailLog;
import freemarker.template.Template;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.mail.javamail.JavaMailSender;

import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.ui.freemarker.FreeMarkerTemplateUtils;
import org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer;

import javax.mail.internet.MimeMessage;
import java.util.HashMap;
import java.util.Map;

public class Singleton { //双检锁/双重校验锁(单例模式)
    private static final Logger LOGGER = LoggerFactory.getLogger(Singleton.class);

    private static class SingletonHolder {
        public final static Singleton instance = new Singleton();
    }

    public static Singleton getInstance() {
        return SingletonHolder.instance;
    }

    public static Map<Object, Object> sendmail(MailLog mailLog, JavaMailSender mailSender, String mailFrom, String password, FreeMarkerConfigurer freeMarkerConfigurer) {
        Map<Object, Object> map = new HashMap<Object, Object>();
//                发邮件
        MimeMessage message = null;
        try {
            message = mailSender.createMimeMessage();
            MimeMessageHelper helper = new MimeMessageHelper(message, true);
            helper.setFrom(mailFrom);
            helper.setTo(mailLog.getMailTo());
            helper.setSubject(mailLog.getRefAction());
            Map<String, Object> model = new HashMap<>();
            String mailtemplatsPath = "";
            if (103 == mailLog.getResType()) {
                model.put("resTypeName", "服务资源");
            } else if (102 == mailLog.getResType()) {
                model.put("resTypeName", "云资源");
            } else if (101 == mailLog.getResType()) {
                model.put("resTypeName", "广告资源");
            }
            model.put("refName", mailLog.getRefName());
            model.put("refQuota", mailLog.getRefQuota());
            if ((mailLog.getRefAction()).equals("额度发放")) {
                mailtemplatsPath = "mailtemplats/sendQuota.ftl";
            } else if ((mailLog.getRefAction()).equals("额度使用")) {
                mailtemplatsPath = "mailtemplats/useQuota.ftl";
            } else if ((mailLog.getRefAction()).equals("额度返还")) {
                mailtemplatsPath = "mailtemplats/backQuota.ftl";
            }
            //读取 ftl 模板
            Template template = freeMarkerConfigurer.getConfiguration().getTemplate(mailtemplatsPath);
            String html = FreeMarkerTemplateUtils.processTemplateIntoString(template, model);
            helper.setText(html, true);
            map.put("id", mailLog.getId());
            map.put("mailState", true);
            map.put("mailResCode", 1);
            map.put("mailResMsg", "发送成功");
            map.put("mailCount", null);
            LOGGER.info("发送成功");
        } catch (Exception e) {
            e.printStackTrace();
            map.put("id", mailLog.getId());
            map.put("mailState", false);
            map.put("mailResCode", 0);
            map.put("mailResMsg", e.toString());
            map.put("mailCount", 1);

            LOGGER.info("发送失败");
            LOGGER.info(e.toString());
        }
        mailSender.send(message);
        LOGGER.info("邮件已经发送-----");
        return map;
    }

}-------------

package com.manage.util;

import com.alibaba.fastjson.JSON;
import com.w3china.mingjing3.manage.service.MailLogService;
import com.w3china.mingjing3.model.MailLog;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import java.util.*;

import org.slf4j.Logger;
import org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer;

@Component
@Configurable
@EnableScheduling
public class ScheduledTasks {
    private static final Logger LOGGER = LoggerFactory.getLogger(ScheduledTasks.class);
    @Autowired
    private JavaMailSender mailSender; //自动注入的Bean
    @Value("${spring.mail.username}")
    private String mailFrom; //读取配置文件中的参数
    @Value("${spring.mail.password}")
    private String password; //读取配置文件中的参数
    @Autowired
    private FreeMarkerConfigurer freeMarkerConfigurer;  //自动注入
    @Autowired
    private MailLogService mailLogService;

//      fixedRate 每次任务结束后会从任务编排表中找下一次该执行的任务，判断是否到时机执行。
//      fixedRate 的任务某次执行时间再长也不会造成两次任务实例同时执行，除非用了 @Async 注解。
//      fixedDelay 总是前一次任务完成后，延时固定时间然后执行一次任务

    @Scheduled(cron = "${scheduled.cron}")
    public void reportCurrentByCron() {
        LOGGER.info("ScheduledTasks开始定时执行");
        List<MailLog> mailLogList = mailLogService.selectByMailState(100); //
        Queue<MailLog> queue = new LinkedList<MailLog>();
        if (queue.isEmpty()) {
            for (int i = 0; i < mailLogList.size(); i++) { // 队列为空的话，就将集合放到队列里
                queue.offer(mailLogList.get(i));
            }
        }
        LOGGER.info(JSON.toJSONStringWithDateFormat("queque==" + queue, "yyyy-MM-dd HH:mm:ss"));
        Singleton singleton = Singleton.getInstance();
//            queue.poll(); //返回第一个元素，并在队列中删除
        Map<Object, Object> sendmail = singleton.sendmail(queue.poll(), mailSender, mailFrom, password, freeMarkerConfigurer);

        mailLogService.updateMailLogById( // 更新数据库邮件记录表
                (Integer) sendmail.get("id"),
                (Boolean) sendmail.get("mailState"),
                (Integer) sendmail.get("mailResCode"),
                (String) sendmail.get("mailResMsg"),
                (Integer) sendmail.get("mailCount")
        );

    }

}

----------------
manage\src\main\resources\templates\mailtemplats\sendQuota.ftl

<html>

<body>
<#--额度发放 邮箱模板-->
<h3>
    您好，您提交的${resTypeName!}资源中${refName!}项目的资源申请已通过审核，发放额度${refQuota!}元，请登录系统使用。
</h3>
<#--注意：只给公司业务联系人的邮箱发送-->
</body>

</html>