使用Commons Email发送邮件以及与Spring的结合

使用Maven构建项目，在pom.xml中添加依赖包，

<dependencies>
    ...
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-email</artifactId>
        <version>1.3.3</version>
    </dependency>
</dependencies>

参考User guide，基于QQ邮箱发送文本邮件，

public static void main(String[] args) {
    Email email = new SimpleEmail();
    // 连接参数配置
    email.setHostName("smtp.qq.com");
    email.setSmtpPort(465);
    email.setAuthenticator(new DefaultAuthenticator("QQ No", "QQ Password");
    email.setSSLOnConnect(true);
    // 邮件相关内容
    try {
        email.setFrom("from@qq.com");
        email.setMsg("Hello, world!");
        email.addTo("to@example.com");
        email.send();
    } catch (EmailException e) {

    }
}

与使用JDBC连接数据库一样，前面的代码包含大量的模板操作，所以结合Spring，与JdbcTemplate类似，构建MailTemplate。在applicationContext-mail.xml中声明Bean，

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

    <bean id="simpleMail" class="org.apache.commons.mail.SimpleEmail">
        <property name="hostName" value="${me.mail.hostName}" />
        <property name="smtpPort" value="${me.mail.smtpPort}" />
        <property name="from" value="${me.mail.from}" />
        <property name="authenticator">
            <bean class="org.apache.commons.mail.DefaultAuthenticator">
                <constructor-arg value="${me.mail.authenticator.userName}" />
                <constructor-arg value="${me.mail.authenticator.password}" />
            </bean>
        </property>
    </bean>

    <bean id="mailTemplate" class="me.voler.jechat.core.MailTemplate">
        <property name="simpleMail" ref="simpleMail" />
    </bean>
</beans>

将连接参数添加到mail.properties，me.voler.jechat.core.MailTemplate即构建的MailTemplate，

package me.voler.jechat.core;

import org.apache.commons.mail.EmailException;
import org.apache.commons.mail.SimpleEmail;

public class MailTemplate {

    private SimpleEmail simpleMail;

    public void send(String msg, String to) {
        this.send("【邮件】", msg, to);
    }

    /**
     * 
     * @param subject 邮件主题
     * @param msg 邮件正文
     * @param toList 收件人列表
     */
    public void send(String subject, String msg, String... toList) {

        try {
            simpleMail.setSubject(subject);
            simpleMail.setMsg(msg);
            simpleMail.addTo(toList);

            simpleMail.setSSLOnConnect(true);
            simpleMail.send();
        } catch (EmailException e) {
            e.printStackTrace();
        }

    }

    public SimpleEmail getSimpleMail() {
        return simpleMail;
    }

    public void setSimpleMail(SimpleEmail simpleMail) {
        this.simpleMail = simpleMail;
    }

}

使用构建的MailTemplate发送文本邮件，

@Autowired
@Qualifier("mailTemplate")
private MailTemplate mailTemplate;

public void sendEmptyMail() {
    mailTemplate.send("中文测试，English Test.", "to@example.com");
}

SimpleEmail的父类的属性sslOnConnect的set方法名为setSSLOnConnect，如果直接在applicationContext-mail.xml的simpleMail Bean下配置<property name="sslOnConnect" value="${me.mail.sslOnConnect}" />会提示Bean property is not writable or has an invalid setter method