server:
  port: 12032
  servlet:
    context-path: /laokou-demo
spring:
  application:
    name: laokou-third-party-email-demo
  mail:
    default-encoding: UTF-8
    host: smtp.qq.com
    username: 你的邮箱地址
    password: 授权码
    properties:
      mail:
        smtp:
          auth: true
          starttls:
            enable: true
            required: true

package io.laokou.email.utils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.stereotype.Component;
import java.util.Date;
/**
 * TODO
 *
 * @author Kou Shenhai 2413176044
 * @version 1.0
 */
@Component
public class EmailUtil {
    @Autowired
    private JavaMailSender sender;
    @Value("${spring.mail.username}")
    private String fromUser;
    public Integer send() {
        try{
            // 构建一个邮件对象
            SimpleMailMessage message = new SimpleMailMessage();
            //发送人
            message.setFrom(fromUser);
            //接收人
            message.setTo(你发给哪个人的邮箱);
            //邮件主题
            message.setSubject("验证码");
            //邮件时间
            message.setSentDate(new Date());
            //邮件内容
            message.setText(String.format("验证码:%s，您正在登录，若非本人操作，请勿泄露。", 233232));
            sender.send(message);
            return 1;
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("error："+e.getMessage());
            return 0;
        }
    }
}

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.0.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.17</version>
        </dependency>

spring.jackson.time-zone=GMT+8
spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
mybatis-plus.mapper-locations=classpath:/mybatis/mapper/*.xml
mybatis-plus.type-aliases-package=io.laokou.freemarker.entity
mybatis-plus.global-config.db-config.id-type=id_worker
mybatis-plus.global-config.db-config.field-strategy=not_null
mybatis-plus.global-config.db-config.column-like=true
mybatis-plus.global-config.banner=false
mybatis-plus.configuration.map-underscore-to-camel-case=true
mybatis-plus.configuration.cache-enabled=false
mybatis-plus.configuration.call-setters-on-nulls=true
spring.datasource.druid.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.druid.url=jdbc:mysql://127.0.0.1:3306/kcloud?serverTimezone=CTT&useUnicode=true&characterEncoding=utf-8&allowMultiQueries=true
spring.datasource.druid.username=root
spring.datasource.druid.password=123456
spring.datasource.druid.initial-size=10
spring.datasource.druid.max-active=100
spring.datasource.druid.min-idle=10
spring.datasource.druid.max-wait=60000
spring.datasource.druid.pool-prepared-statements=true
spring.datasource.druid.max-pool-prepared-statement-per-connection-size=20
spring.datasource.druid.time-between-eviction-runs-millis=60000
spring.datasource.druid.min-evictable-idle-time-millis=300000
spring.datasource.druid.test-while-idle=true
spring.datasource.druid.test-on-borrow=false
spring.datasource.druid.test-on-return=false
spring.datasource.druid.stat-view-servlet.enabled=true
spring.datasource.druid.stat-view-servlet.url-pattern=/druid/**
spring.datasource.druid.stat-view-servlet.login-username=root
spring.datasource.druid.stat-view-servlet.login-password=123456
spring.datasource.druid.filter.stat.log-slow-sql=true
spring.datasource.druid.filter.stat.slow-sql-millis=1000
spring.datasource.druid.filter.stat.merge-sql=false
spring.datasource.druid.filter.wall.config.multi-statement-allow=true

public class TemplateUtil {
    public static String getTemplate(String templateContent,Map<String,Object> params) throws IOException, TemplateException {
        //Freemarker配置
        Configuration configuration = new Configuration(Configuration.getVersion());
        configuration.setLocale(Locale.CHINA);
        configuration.setDefaultEncoding("UTF-8");
        StringTemplateLoader loader = new StringTemplateLoader();
        //略过替换部分标签
        loader.putTemplate("templates",templateContent);
        configuration.setTemplateLoader(loader);
        Template template = configuration.getTemplate("templates","utf-8");
        StringWriter result = new StringWriter();
        template.process(params,result);
        return result.toString();
    }
}