一：普通方式发送

1.导包

        <!--Java MAil 发送邮件API-->
        <dependency>
            <groupId>javax.mail</groupId>
            <artifactId>javax.mail-api</artifactId>
            <version>1.6.1</version>
        </dependency>
        <!-- 真正的实现库 -->
        <dependency>
            <groupId>com.sun.mail</groupId>
            <artifactId>javax.mail</artifactId>
            <version>1.6.1</version>
        </dependency>

2.代码

• 实例：通过一个已知的163邮箱发送给他人邮件

    public static void main(String[] args) throws MessagingException {
        // 1.创建一个程序与邮件服务器会话对象 Session
        Properties props = new Properties();
        props.setProperty("mail.transport.protocol", "SMTP");
        props.setProperty("mail.smtp.host", "smtp.163.com");
        props.setProperty("mail.smtp.port", "25");
        // 指定验证为true
        props.setProperty("mail.smtp.auth", "true");
        props.setProperty("mail.smtp.timeout", "1000");
        // 验证账号及密码，密码对应邮箱授权码（163密码可行，qq必须授权码）
        Authenticator auth = new Authenticator() {
            public PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication("xxxx@163.com", "xxxxx");
            }
        };
        Session session = Session.getInstance(props, auth);

        // 2.创建一个Message，它相当于是邮件内容
        Message message = new MimeMessage(session);
        // 设置发送者
        message.setFrom(new InternetAddress("xxx同上xxx@163.com"));
        // 设置发送方式与接收者
        message.setRecipient(MimeMessage.RecipientType.TO, new InternetAddress("xx10086xx@qq.com"));
        // 设置主题
        message.setSubject("邮件发送测试");
        // 设置内容
        message.setContent("Hello!", "text/html;charset=utf-8");

        // 3.创建 Transport用于将邮件发送
        Transport.send(message);
    }

二：SpringBoot的JavaMailSenderImpl发送

1.在resources下新建mailConfig.properties

mailConfig.properties
#服务器
mailHost=smtp.163.com
#端口号
mailPort=25
#邮箱账号(使用者改成自己的)
mailUsername=xxxxxx@163.com
#邮箱密码(使用者改成自己的)
mailPassword=xxxxx
#时间延迟
mailTimeout=25000

2.新建一个类去读这个配置文件的内容

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

/**
 * Create by yster@foxmail.com 2018/5/28/028 21:00
 */
public class MailConfig {
    private static final String PROPERTIES_DEFAULT = "mailConfig.properties";
    public static String host;
    public static Integer port;
    public static String userName;
    public static String passWord;
    public static String emailForm;
    public static String timeout;
    public static String personal;
    public static Properties properties;
    static{
        init();
    }

    /**
     * 初始化
     */
    private static void init() {
        properties = new Properties();
        try{
            InputStream inputStream = MailConfig.class.getClassLoader().getResourceAsStream(PROPERTIES_DEFAULT);
            properties.load(inputStream);
            inputStream.close();
            host = properties.getProperty("mailHost");
            port = Integer.parseInt(properties.getProperty("mailPort"));
            userName = properties.getProperty("mailUsername");
            passWord = properties.getProperty("mailPassword");
            emailForm = properties.getProperty("mailUsername");
            timeout = properties.getProperty("mailTimeout");
            personal = "来自星星的我";//发送人
        } catch(IOException e){
            e.printStackTrace();
        }
    }
}

3.以上只是准备阶段，下面开始邮件编码

import cn.zyzpp.config.MailConfig;
import org.springframework.mail.javamail.JavaMailSenderImpl;
import org.springframework.mail.javamail.MimeMessageHelper;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import java.io.UnsupportedEncodingException;
import java.util.Properties;

/**
 * Create by yster@foxmail.com 2018/5/28/028 21:05
 */
public class MailUtil {
    private static final String HOST = MailConfig.host;
    private static final Integer PORT = MailConfig.port;
    private static final String USERNAME = MailConfig.userName;
    private static final String PASSWORD = MailConfig.passWord;
    private static final String emailForm = MailConfig.emailForm;
    private static final String timeout = MailConfig.timeout;
    private static final String personal = MailConfig.personal;
    private static JavaMailSenderImpl mailSender = createMailSender();
    /**
     * 邮件发送器
     *
     * @return 配置好的工具
     */
    private static JavaMailSenderImpl createMailSender() {
        JavaMailSenderImpl sender = new JavaMailSenderImpl();
        sender.setHost(HOST);
        sender.setPort(PORT);
        sender.setUsername(USERNAME);
        sender.setPassword(PASSWORD);
        sender.setDefaultEncoding("Utf-8");
        Properties p = new Properties();
        p.setProperty("mail.smtp.timeout", timeout);
        p.setProperty("mail.smtp.auth", "false");
        sender.setJavaMailProperties(p);
        return sender;
    }

    /**
     * 发送邮件
     *
     * @param to 接受人
     * @param subject 主题
     * @param html 发送内容
     * @throws MessagingException 异常
     * @throws UnsupportedEncodingException 异常
     */
    public static void sendMail(String to, String subject, String html) throws MessagingException,UnsupportedEncodingException {
        MimeMessage mimeMessage = mailSender.createMimeMessage();
        // 设置utf-8或GBK编码，否则邮件会有乱码
        MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage, true, "UTF-8");
        messageHelper.setFrom(emailForm, personal);
        messageHelper.setTo(to);
        messageHelper.setSubject(subject);
        messageHelper.setText(html, true);
        mailSender.send(mimeMessage);
    }

4.开始发送一封邮件

    public static void main(String[] args){
        try {
            MailUtil.sendMail("xxxx@qq.com", "标题", "内容");
        } catch (MessagingException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
    }

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