Spring集成JavaMail並利用線程池發送郵件

　　我們系統存在大量發送郵件的需求，項目使用的是Spring框架而JavaMail也能很好的跟Spring進行集成，由於發送郵件最好還是使用異步進行發送，所以這里就采用線程池+JavaMail進行郵件發送，下面看具體代碼實現：

　　Step1、引入JavaMail

<mail.version>1.4.7</mail.version>
<dependency>
      <groupId>javax.mail</groupId>
      <artifactId>mail</artifactId>
      <version>${mail.version}</version>
</dependency>

　　Step2、Spring配置文件中配置MailSender和線程池

 <!--MailSender-->
    <bean id="javaMailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
        <property name="host" value="${email.host}"/>
        <property name="username" value="${email.username}"/>
        <property name="password" value="${email.password}"/>
        <property name="javaMailProperties">
            <props>
                <prop key="mail.smtp.auth">true</prop>
                <prop key="mail.smtp.timeout">25000</prop>
                <!--
                <prop key="mail.smtp.starttls.enable">true</prop>
                <prop key="mail.smtp.socketFactory.class">javax.net.ssl.SSLSocketFactory</prop>
                -->
            </props>
        </property>
    </bean>


    <!--配置線程池-->
    <bean id="taskExecutor" class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
        <!-- 核心線程數 -->
        <property name="corePoolSize" value="${executor.corePoolSize}" />
        <!-- 最大線程數 -->
        <property name="maxPoolSize" value="${executor.maxPoolSize}" />
        <!-- 最大隊列數 -->
        <property name="queueCapacity" value="${executor.queueCapacity}" />
        <!-- 線程池維護線程所允許的空閑時間 -->
        <property name="keepAliveSeconds" value="${executor.keepAliveSeconds}" />
    </bean>

　　Step3、新建郵件實體類，方便業務處理

import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.util.Assert;

import javax.mail.internet.AddressException;
import java.util.Arrays;

/**
 * <p>
 * <code>MailEntry</code>
 * </p>
 * Description:
 * 郵件實體類
 * @author jianzh5
 * @version 2017/3/31 17:00
 * @since 1.0
 */
public class MailEntry {
    /**
     * 收件人
     */
    private String[] recipients;
    /**
     * 抄送人
     */
    private String[] carbonCopy;
    /**
     * 主題
     */
    private String subject;
    /**
     * 內容
     */
    private String text;

    public String getSubject() {
        return subject;
    }

    public void setSubject(String subject) {
        this.subject = subject;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public String[] getRecipients() {
        return recipients.clone();
    }

    public void setRecipients(String[] recipients) throws AddressException {
        Assert.isTrue(ArrayUtils.isNotEmpty(recipients),"收件人不能為空");
        String[] addresses = new String[recipients.length];
        for (int i = 0; i < addresses.length; i++) {
            addresses[i] = parseAddress(recipients[i]);
        }
        this.recipients = addresses;
    }

    public String[] getCarbonCopy() {
        if(ArrayUtils.isNotEmpty(carbonCopy)){
            return carbonCopy.clone();
        }
        return ArrayUtils.EMPTY_STRING_ARRAY;
    }

    public void setCarbonCopy(String[] carbonCopy) throws AddressException {
        String[] addresses = new String[carbonCopy.length];
        for (int i = 0; i < addresses.length; i++) {
            addresses[i] = parseAddress(carbonCopy[i]);
        }
        this.carbonCopy = addresses;
    }

    /**
     * @desc 只要設定郵件接受人的域賬號即可自動增加企業后綴
     * @author jianzh5
     * @date 2017/4/1 13:43
     * @param recipient 收件人域賬號
     * @return 帶企業后綴的郵箱地址
     * @throws AddressException
     */
    private String parseAddress(String recipient) throws AddressException {
        if(StringUtils.isEmpty(recipient)){
            throw new AddressException("郵箱賬號不能為空",recipient);
        }
        return recipient + "@company.com";
    }

    @Override public String toString() {
        return "MailEntry{" +
                "recipients=" + Arrays.toString(recipients) +
                ", carbonCopy=" + Arrays.toString(carbonCopy) +
                ", subject='" + subject + '\'' +
                ", text='" + text + '\'' +
                '}';
    }
}

　　說明：由於我們是使用企業郵箱發送郵件，而一般業務都只能取到公司用戶名而非真正的郵箱地址，所以在上面實體類里進行了一次轉換，如果能直接拿到郵箱地址的話上面的轉換是不需要的。收件人和抄送人都是支持數組形式的參數，所以在這里直接使用數組作為收件人、抄送人屬性，發送郵件的時候只要直接設置成數組參數即可。

　　Step4、發送郵件業務層實現

import org.apache.commons.lang3.ArrayUtils;
import org.springframework.core.task.TaskExecutor;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;

/**
 * <p>
 * <code>MailServiceImpl</code>
 * </p>
 * Description:
 * 郵件系統實現類
 * @author jianzh5
 * @version 2017/3/31 17:10
 * @since 1.0
 */

@Service
public class MailServiceImpl implements IMailService{
    private LoggerUtil logger = LoggerUtil.getLogger(this.getClass());

    @Resource
    private TaskExecutor taskExecutor;
    @Resource
    private JavaMailSender javaMailSender;



    @Override
    public void sendMail(MailEntry mailEntry) {
        MimeMessage message = javaMailSender.createMimeMessage();
        try {
            MimeMessageHelper helper = new MimeMessageHelper(message, true, "utf-8");
            helper.setFrom("[e-mail]");
            helper.setTo(mailEntry.getRecipients()); //收件人
            if(ArrayUtils.isNotEmpty(mailEntry.getCarbonCopy())){
                helper.setCc(mailEntry.getCarbonCopy()); //抄送人
            }
            helper.setSubject(mailEntry.getSubject());
            helper.setText(mailEntry.getText(),true);//設置為TRUE則可以使用Html標記
            addSendMailTask(message);
        } catch (MessagingException e) {
//            e.printStackTrace();
            logger.error("郵件轉換異常,郵件詳細信息為{}",e.getMessage());
        }


    }

    /**
     * @desc 使用多線程發送郵件
     * @author jianzh5
     * @date 2017/4/1 11:41
     * @param message MimeMessage郵件封裝類
     */
    private void addSendMailTask(final MimeMessage message){
        try{
            taskExecutor.execute(new Runnable() {
                @Override
                public void run() {
                    javaMailSender.send(message);
                }
            });
        }catch (Exception e){
            logger.error("郵件發送異常,郵件詳細信息為{}",e.getMessage());
        }

    }
}