Spring 高效批量邮件发送
Gmail 邮件发送配置
email.properties 文件：
# Gmail Configuration
email.host=smtp.gmail.com
email.port=587
email.username=******
email.password=******
email.defaultEncoding=UTF-8
applicationContext.xml 文件：
<!-- Email Service -->
<bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
<property name="host" value="${email.host}"/>
<property name="port" value="${email.port}"/>
<property name="username" value="${email.username}"/>
<property name="password" value="${email.password}"/>
<property name="javaMailProperties">
<props>
<prop key="mail.transport.protocol">smtp</prop>
<prop key="mail.smtp.starttls.enable">true</prop>
<prop key="mail.smtp.host">smtp.gmail.com</prop>
<prop key="mail.smtp.auth">true</prop>
<prop key="mail.smtp.port">465 </prop>
</props>
<!--
<value>
mail.smtp.auth=true
</value>
-->
</property>
<property name="defaultEncoding" value="${email.defaultEncoding}"></property>
</bean>
<bean id="emailSender" class="com.tucue.common.util.SimpleEmailSender">
<property name="mailSender" ref="mailSender"></property>
</bean>
<!-- end of Email Service -->
FAQ ：
com .sun .mail .smtp .SMTPSendFailedException: 530 5 .7 . 0 Must issue a STARTTLS command first .
A ：
<prop key="mail.smtp.starttls.enable">true</prop>
Send Batch Mail
http://static.springsource.org/spring/docs/2.5.x/api/org/springframework/mail/MailSender .html
Method Summary
void |
send (SimpleMailMessage simpleMessage) Send the given simple mail message. |
void |
send (SimpleMailMessage [] simpleMessages) Send the given array of simple mail messages in batch. |
Method Summary
MimeMessage |
createMimeMessage () Create a new JavaMail MimeMessage for the underlying JavaMail Session of this sender. |
MimeMessage |
createMimeMessage (InputStream contentStream) Create a new JavaMail MimeMessage for the underlying JavaMail Session of this sender, using the given input stream as the message source. |
void |
send (MimeMessage mimeMessage) Send the given JavaMail MIME message . |
void |
send (MimeMessage [] mimeMessages) Send the given array of JavaMail MIME messages in batch . |
void |
send (MimeMessagePreparator mimeMessagePreparator) Send the JavaMail MIME message prepared by the given MimeMessagePreparator. |
void |
send (MimeMessagePreparator [] mimeMessagePreparators) Send the JavaMail MIME messages prepared by the given MimeMessagePreparators. |
方案一：首先获取要发送邮件的所有地址，然后迭代的封装单个 MimeMessage 之后就将其发送出去（即发送一封邮件）。
SimpleEmailSender.java 文件
/**
* 功能: 传入邮件接收者地址、标题和内容，然后发送单个邮件服务
* @param {@link String} emailAddress
* @param {@link String} subject
* @param {@link String} content
* @throws MessagingException
*/
public static void sendSimpleEmail(String receiver
, String subject, String content) throws MessagingException {
JavaMailSender sender = (JavaMailSender) mailSender;
MimeMessage mimeMessage
= sender.createMimeMessage();
MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage, true, "UTF-8");
messageHelper.setFrom("***@gmail
.com");
messageHelper.setTo(receiver);
messageHelper.setSubject(subject);
messageHelper.setText(content, true);
sender.send(mimeMessage
);
}
UserInfoAction.java 文件
// 用户 -> 批量邮件发送
public String sendBatchEmail() {
if(!emailReceiverList.equals("")) { // 发送用户邮件
// String[] receiverList = emailReceiverList.split(",");
String[] receiverList = new String[20];
for(int i = 0; i < 20; ++i) {
receiverList[i] = "[email protected]";
}
long start = System.currentTimeMillis();
for(String receiver: receiverList
) {
try {
SimpleEmailSender.sendSimpleEmail(receiver, emailSubject, emailContent);
} catch (MessagingException e) {
e.printStackTrace();
}
}
long end = System.currentTimeMillis();
System.out.println(end - start);
} else {// 发送用户组邮件
List<String> receiverList = userInfoService.getUserEmailByGroupId(groupID);
for(String receiver: receiverList) {
try {
SimpleEmailSender.sendSimpleEmail(receiver, emailSubject, emailContent);
} catch (MessagingException e) {
e.printStackTrace();
}
}
}
return SUCCESS;
}
方案二：首先获取要发送邮件的所有地址，然后一起封装成 MimeMessage[] 之后就将其发送出去（即批量发送所有要发送的邮件）。
SimpleEmailSender.java 文件
/**
* 功能: 传入邮件接收者地址列表、标题和内容，然后发送批量邮件服务
* @param {@link List<String>} receiverList
* @param {@link String} subject
* @param {@link String} content
* @throws MessagingException
*/
public static void sendBulkEmail(List<String> receiverList
, String subject, String content) throws MessagingException {
JavaMailSender sender = (JavaMailSender) mailSender;
int len = receiverList.size();
MimeMessage[] mimeMessageList
= new MimeMessage[len]; // 注意：是数组类型
MimeMessageHelper messageHelper = null;
for(int i = 0; i < len; ++i) {
mimeMessageList[i]
= sender.createMimeMessage();
messageHelper = new MimeMessageHelper(mimeMessageList[i], true, "UTF-8");
messageHelper.setFrom("[email protected]");
messageHelper.setTo(receiverList.get(i));
messageHelper.setSubject(subject);
messageHelper.setText(content, true);
}
sender.send(mimeMessageList
);
}
UserInfoAction.java 文件
// 用户 -> 批量邮件发送
public String sendBatchEmail() {
if(!emailReceiverList.equals("")) { // 发送用户邮件
// String[] receiverList = emailReceiverList.split(",");
List<String> receiverList
= new ArrayList<String>(20);
for(int i = 0; i < 20; ++i) {
receiverList.add("[email protected]");
}
long start = System.currentTimeMillis();
try {
// SimpleEmailSender.sendBulkEmail(Arrays.asList(receiverList), emailSubject, emailContent);
SimpleEmailSender.sendBulkEmail(receiverList
, emailSubject, emailContent);
} catch (MessagingException e) {
e.printStackTrace();
}
long end = System.currentTimeMillis();
System.out.println(end - start);
} else {// 发送用户组邮件
List<String> receiverList = userInfoService.getUserEmailByGroupId(groupID);
try {
SimpleEmailSender.sendBulkEmail(receiverList, emailSubject, emailContent);
} catch (MessagingException e) {
e.printStackTrace();
}
}
return SUCCESS;
}
根据上述两种方案，通过发送 20 封邮件进行测试后发，发现第二种方案（用时 36984 ms）比第一种（81266 ms）的 执行效率 2.1 倍多 。
总结
通过这次实验，感觉自己收获了不少。第一，评价哪种方案优劣，用你需要的数据测试就能体现执行效率，但健壮性和可扩展性就不能一概而论了；第二，要想编写更加高效的代码，就必须对你特别重要（特别是常用基础类）的 API 有足够的熟知。就以这个案例为例，刚开始我没有仔细看过 JavaMailSender 的 API ，导致就不知道用 send (MimeMessage [] mimeMessages) 这个函数，所以也不知道存在第二种方案。后来突然发现有这个函数，就像能不能对先前的发送单个邮件服务加以改进，第二种方案也就是这样萌生的。