Spring的邮件服务支持主要是通过JavaMailSender这个接口实现的：
public interface JavaMailSender extends MailSender {
MimeMessage createMimeMessage();
MimeMessage createMimeMessage(InputStream contentStream) throws MailException;
void send(MimeMessage mimeMessage) throws MailException;
void send(MimeMessage[] mimeMessages) throws MailException;
void send(MimeMessagePreparator mimeMessagePreparator) throws MailException;
void send(MimeMessagePreparator[] mimeMessagePreparators) throws MailException;
}
这是JavaMailSender的接口源代码(去除注释),可以看到，主要提供了createMimeMessage和send两个方法。createMimeMessage方法主要是用来创建JavaMail的MIME信件，而send则是发送电子邮件的主要方法。
Spring中提供了JavaMailSender的简单实现：org.springframework.mail.javamail.JavaMailSenderImpl。在JavaMailSendImpl这个类中，实现了JavaMailSender中定义的方法的具体实现。而众所周知，Spring是核心的功能是IOC，所以通过Spring来发送电子邮件，就可以使用Spring强大的IOC功能，下面就来看一下，怎么样在Spring中发送邮件：
1. Spring配置文件，主要配置mailSender和对velocity的支持
<? xml version="1.0" encoding="UTF-8" ?>
< beans xmlns ="http://www.springframework.org/schema/beans"
xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation ="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd"
default-lazy-init ="true" default-autowire ="byName" >
<!-- 属性文件加载, 加载邮件设置属性文件 -->
< bean id ="propertyConfigurer"
class ="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" >
< property name ="locations" >
< list >
< value > classpath:mail.properties </ value >
</ list >
</ property >
</ bean >
< bean id ="mailEngine" class ="org.example.mailer.MailEngine" >
< property name ="javaMailSender" ref ="javaMailSender" />
< property name ="velocityEngine" ref ="velocityEngine" />
</ bean >
< bean id ="velocityEngine"
class ="org.springframework.ui.velocity.VelocityEngineFactoryBean" >
< property name ="resourceLoaderPath" value ="classpath:velocity" />
</ bean >
<!-- 邮件发送器 -->
< bean id ="javaMailSender" class ="org.springframework.mail.javamail.JavaMailSenderImpl" >
< property name ="host" value ="${mail.host}" />
< property name ="username" value ="${mail.username}" />
< property name ="password" value ="${mail.password}" />
< property name ="defaultEncoding" value ="UTF-8" ></ property >
< property name ="javaMailProperties" >
< props >
< prop key ="mail.smtp.auth" > ${mail.smtp.auth} </ prop >
< prop key ="mail.smtp.timeout" > ${mail.smtp.timeout} </ prop >
</ props >
</ property >
</ bean >
</ beans >
在这个配置文件中，通过 propertyConfigurer这个bean 加载了邮件的配置文件：mail.properties，这个文件主要定义一些邮件服务的属性(使用的时候根据自己的要求进行相应的配置，这里以126的smtp服务为例):
mail.from =
mail.host = smtp. 126 .com
mail.username =
mail.password =
mail.smtp.auth = true
mail.smtp.timeout = 25000
下面来看一下MailEngine 的实现：
package org.example.mailer;
import java.util.Map;
import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.exception.VelocityException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.mail.MailException;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.ui.velocity.VelocityEngineUtils;
public class MailEngine {
protected final Log logger = LogFactory.getLog(getClass());
private JavaMailSender javaMailSender;
private VelocityEngine velocityEngine;
public void setJavaMailSender(JavaMailSender javaMailSender) {
this .javaMailSender = javaMailSender;
}
public void setVelocityEngine(VelocityEngine velocityEngine) {
this .velocityEngine = velocityEngine;
}
public void sendMailWithVelocity() {
MimeMessage msg = javaMailSender.createMimeMessage();
MimeMessageHelper helper = new MimeMessageHelper(msg);
String result = null ;
Map model = null ;
try {
result = VelocityEngineUtils.mergeTemplateIntoString(
velocityEngine, " sendMail.vm " , " UTF-8 " , model); // UTF-8为模板文件的字符编码
helper.setFrom( " 邮件发送者 " );
helper.setSubject( " 测试Spring邮件 " );
helper.setTo( " 邮件接收者 " );
helper.setText(result);
javaMailSender.send(msg);
} catch (VelocityException e) {
e.printStackTrace();
logger.error(e.getMessage());
} catch (MessagingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public boolean senaMail() {
MimeMessage msg = javaMailSender.createMimeMessage();
MimeMessageHelper helper = new MimeMessageHelper(msg);
try {
helper.setFrom( " 邮件发送者 " );
helper.setSubject( " 邮件内容 " );
helper.setTo( " 邮件接收者 " );
helper.setText( " test spring mailer " , true ); // 如果发的不是html内容去掉true参数
javaMailSender.send(msg);
} catch (MessagingException e) {
// TODO 自动生成 catch 块
if (logger.isWarnEnabled()) {
logger.warn( " 邮件信息导常! 邮件标题为: " );
}
return false ;
// e.printStackTrace();
} catch (MailException me) {
// TODO: handle exception
if (logger.isWarnEnabled()) {
logger.warn( " 发送邮件失败! 邮件标题为: " );
}
return false ;
}
return true ;
}
public static void main(String[] args) {
BeanFactory bf = new ClassPathXmlApplicationContext( " beans.xml " );
MailEngine mailEngine = (MailEngine) bf.getBean( " mailEngine " );
// mailEngine.senaMail();
mailEngine.sendMailWithVelocity();
}
}
sendMailWithVelocity方法主要是使用Velocity模板文件来发送邮件，Velocity模板文件定义了邮件的内容,模板文件的位置由 resourceLoaderPath 指定，本例则在classpath下的velocity下，如果是web项目，则位于/WEB-INF/classes/veloticy/目录下。
执行main方法，就可以发送邮件了。