邮件的依赖：

        <!--mail-->
        <dependency>
            <groupId>javax.mail</groupId>
            <artifactId>mail</artifactId>
            <version>1.4.7</version>
        </dependency>

定义邮件的服务类:

public class MailService {
    @Value("${mail.from}")
    private String from;

    @Resource(name = "javaMailSender")
    private JavaMailSender javaMailSender;

    public void sendMail(String subject,String to, String text) {
        sendMail(subject, text, Collections.singletonList(to));
    }

    public void sendMail(String subject, String text, Collection<String> toMails) {
        if (CollectionUtils.isEmpty(toMails)) {
            return;
        }

        for (String toMail : toMails) {
            SimpleMailMessage message = new SimpleMailMessage();
            message.setFrom(from);
            message.setTo(toMail);
            message.setSubject(subject);
            message.setText(text);

            javaMailSender.send(message);
        }
    }
}

这里我们实例化MailService

public class MailConfig {

    @Value("${mail.host}")
    private String host;
    @Value("${mail.port}")
    private int port;
    @Value("${mail.username}")
    private String username;
    @Value("${mail.password}")
    private String password;
    @Value("${mail.protocol:smtp}")
    private String protocol;
    @Value("${mail.defaultEncoding:UTF-8}")
    private String defaultEncoding;

    @Bean(name = "javaMailSender")
    public JavaMailSender javaMailSender() {
        System.setProperty("https.protocols", "TLSv1.1");

        JavaMailSenderImpl sender = new JavaMailSenderImpl();
        sender.setHost(host);
        sender.setPort(port);
        sender.setUsername(username);
        sender.setPassword(password);
        sender.setProtocol(protocol);
        sender.setDefaultEncoding(defaultEncoding);

        Properties properties = new Properties();
        properties.setProperty("mail.smtp.auth", "true");//开启认证
        properties.setProperty("mail.debug", "true");//启用调试
        properties.setProperty("mail.smtp.timeout", "10000");//设置链接超时
        properties.setProperty("mail.smtp.port", Integer.toString(port));//设置端口
        properties.setProperty("mail.smtp.socketFactory.port", Integer.toString(port));//设置ssl端口
        properties.setProperty("mail.smtp.socketFactory.fallback", "false");
        properties.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

        sender.setJavaMailProperties(properties);
        return sender;
    }
}

测试一下:

public class MailTest {

    public static void main(String[] args) {
        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:/test-applicationContext-web.xml");
        applicationContext.start();

        String subject = "test-出现异常-subject";
        String text = "test-出现异常";
        String to = "xxx@xxx.com";

        MailService mailService = applicationContext.getBean(MailService.class);
        mailService.sendMail(subject,to,text);

        try {
            //等待一下,防止邮件还没发送出程序就结束了
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

}

test-applicationContext-web.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.navercorp.pinpoint.web.config.mail,com.navercorp.pinpoint.web.mail"/>

    <bean id="mailConfig" class="com.navercorp.pinpoint.web.config.mail.MailConfig"/>
    <bean id="mailService" class="com.navercorp.pinpoint.web.mail.MailService"/>

    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>classpath:mail.properties</value>
            </list>
        </property>
    </bean>
</beans>

mail.properties
这里需要注意一下下,mail.host,mail.port不同的厂商(qq,163等)不一样.

mail.host=smtp.exmail.qq.com
mail.port=465
mail.username=xxx@xxx.cn
mail.password=xxx
mail.protocol=smtp
mail.defaultEncoding=UTF-8
mail.from=xxx@xx.cn