本文主要介绍如何使用简单的Spring邮件抽象层来实现邮件发送功能，对于JavaMail中的API并不做介绍。通过对比JavaMail的API和Spring的邮件抽象层，我觉得，Spring的邮件抽象层优点就是简化了代码量，并能充分利用IOC功能；缺点就是要使用部分Spring
API，使程序与第三方框架耦合。关于这方面的内容，可以参考Spring的参考手册。
闲言少叙，现在就说说Spring邮件抽象层。这里将要用的接口和类有：
1
）
MailSender
，它是发送邮件的主要接口，代码如下：
public
interface
MailSender {
/**
*
Send
the
given
simple
mail
message.
*
@param
simpleMessage
the
message
to
send
*
@throws
org.springframework.mail.MailParseException
*
in
case
of
failure
when
parsing
the
message
*
@throws
org.springframework.mail.MailAuthenticationException
*
in
case
of
authentication
failure
*
@throws
org.springframework.mail.MailSendException
*
in
case
of
failure
when
sending
the
message
*/
void
send(SimpleMailMessage simpleMessage)
throws
MailException;
/**
*
Send
the
given
array
of
simple
mail
messages
in
batch.
*
@param
simpleMessages
the
messages
to
send
*
@throws
org.springframework.mail.MailParseException
*
in
case
of
failure
when
parsing
a
message
*
@throws
org.springframework.mail.MailAuthenticationException
*
in
case
of
authentication
failure
*
@throws
org.springframework.mail.MailSendException
*
in
case
of
failure
when
sending
a
message
*/
void
send(SimpleMailMessage[] simpleMessages)
throws
MailException;
}
2
）一个简单邮件信息的实现类
SimpleMailMessage
。
3
）
JavaMailSender
接口，提供使用
JavaMail
中
MimeMessage
，代码如下：
public
interface
JavaMailSender
extends
MailSender {
/**
*
Create
a
new
JavaMail
MimeMessage
for
the
underlying
JavaMail
Session
*
of
this
sender.
Needs
to
be
called
to
create
MimeMessage
instances
*
that
can
be
prepared
by
the
client
and
passed
to
send(MimeMessage).
*
@return
the
new
MimeMessage
instance
*
@see
#send(MimeMessage)
*
@see
#send(MimeMessage[])
*/
MimeMessage
createMimeMessage();
/**
*
Create
a
new
JavaMail
MimeMessage
for
the
underlying
JavaMail
Session
*
of
this
sender,
using
the
given
input
stream
as
the
message
source.
*
@param
contentStream
the
raw
MIME
input
stream
for
the
message
*
@return
the
new
MimeMessage
instance
*
@throws
org.springframework.mail.MailParseException
*
in
case
of
message
creation
failure
*/
MimeMessage
createMimeMessage(InputStream contentStream)
throws
MailException;
/**
*
Send
the
given
JavaMail
MIME
message.
*
The
message
needs
to
have
been
created
with
{@link
#createMimeMessage()}
.
*
@param
mimeMessage
message
to
send
*
@throws
org.springframework.mail.MailAuthenticationException
*
in
case
of
authentication
failure
*
@throws
org.springframework.mail.MailSendException
*
in
case
of
failure
when
sending
the
message
*
@see
#createMimeMessage
*/
void
send(MimeMessage mimeMessage)
throws
MailException;
/**
*
Send
the
given
array
of
JavaMail
MIME
messages
in
batch.
*
The
messages
need
to
have
been
created
with
{@link
#createMimeMessage()}
.
*
@param
mimeMessages
messages
to
send
*
@throws
org.springframework.mail.MailAuthenticationException
*
in
case
of
authentication
failure
*
@throws
org.springframework.mail.MailSendException
*
in
case
of
failure
when
sending
a
message
*
@see
#createMimeMessage
*/
void
send(MimeMessage[] mimeMessages)
throws
MailException;
/**
*
Send
the
JavaMail
MIME
message
prepared
by
the
given
MimeMessagePreparator.
*
<p>
Alternative
way
to
prepare
MimeMessage
instances,
instead
of
*
{@link
#createMimeMessage()}
and
{@link #send(MimeMessage)}
calls.
*
Takes
care
of
proper
exception
conversion.
*
@param
mimeMessagePreparator
the
preparator
to
use
*
@throws
org.springframework.mail.MailPreparationException
*
in
case
of
failure
when
preparing
the
message
*
@throws
org.springframework.mail.MailParseException
*
in
case
of
failure
when
parsing
the
message
*
@throws
org.springframework.mail.MailAuthenticationException
*
in
case
of
authentication
failure
*
@throws
org.springframework.mail.MailSendException
*
in
case
of
failure
when
sending
the
message
*/
void
send(MimeMessagePreparator mimeMessagePreparator)
throws
MailException;
/**
*
Send
the
JavaMail
MIME
messages
prepared
by
the
given
MimeMessagePreparators.
*
<p>
Alternative
way
to
prepare
MimeMessage
instances,
instead
of
*
{@link
#createMimeMessage()}
and
{@link #send(MimeMessage[])}
calls.
*
Takes
care
of
proper
exception
conversion.
*
@param
mimeMessagePreparators
the
preparator
to
use
*
@throws
org.springframework.mail.MailPreparationException
*
in
case
of
failure
when
preparing
a
message
*
@throws
org.springframework.mail.MailParseException
*
in
case
of
failure
when
parsing
a
message
*
@throws
org.springframework.mail.MailAuthenticationException
*
in
case
of
authentication
failure
*
@throws
org.springframework.mail.MailSendException
*
in
case
of
failure
when
sending
a
message
*/
void
send(MimeMessagePreparator[] mimeMessagePreparators)
throws
MailException;
}
4
）
MimeMessagePreparator
，支持
MimeMessage
的回调接口，代码如下：
public
interface
MimeMessagePreparator {
/**
*
Prepare
the
given
new
MimeMessage
instance.
*
@param
mimeMessage
the
message
to
prepare
*
@throws
javax.mail.MessagingException
passing
any
exceptions
thrown
by
MimeMessage
*
methods
through
for
automatic
conversion
to
the
MailException
hierarchy
*
@throws
java.io.IOException
passing
any
exceptions
thrown
by
MimeMessage
methods
*
through
for
automatic
conversion
to
the
MailException
hierarchy
*
@throws
Exception
if
mail
preparation
failed,
for
example
when
a
*
Velocity
template
cannot
be
rendered
for
the
mail
text
*/
void
prepare(MimeMessage mimeMessage)
throws
Exception;
}
使用
JavaMail
，需要依赖
mail.jar
和
activation.jar
两个包。利用
Spring
的
IOC
优势，可以通过配置文件来配置邮件发送信息。对于
MailSender
，
Spring
提供了实现类
JavaMailSenderImpl
，可以如下配置
MailSender
信息。
<
bean
id
=
"mailSender"
class
=
"org.springframework.mail.javamail.JavaMailSenderImpl"
>
<
property
name
=
"host"
value
=
"smtp.126.com"
></
property
>
<
property
name
=
"javaMailProperties"
>
<
props
>
<
prop
key
=
"mail.smtp.auth"
>
true
</
prop
>
<
prop
key
=
"mail.smtp.timeout"
>
20000
</
prop
>
</
props
>
</
property
>
<
property
name
=
"username"
value
=
"kafka0102"
></
property
>
<
property
name
=
"password"
value
=
"****"
></
property
>
</
bean
>
可以想到，如果是在
Service
中调用
mailSender
，可以通过
IOC
将
mailSender
注入到
Service
中。这里给出一个简单的使用演示：
BeanFactory
bf =
new
ClassPathXmlApplicationContext(
"service-applicationContext.xml"
);
MailSender
ms = (MailSender)bf.getBean(
"mailSender"
);
SimpleMailMessage
smm =
new
SimpleMailMessage();
smm.setTo(
"kafka0102@126.com"
);
smm.setFrom(
"kafka0102@126.com"
);
smm.setSubject(
"hello"
);
smm.setText(
"I
am you"
);
ms.send(smm);
其中，
SimpleMailMessage
也可以通过配置文件配置使用到的属性。
SimpleMailMessage
不能发送带有附件的邮件，这时就需要
JavaMailSender
（它的实现类也是
JavaMailSenderImpl
），
MimeMessagePreparator
的实现类和部分
JavaMail
API
。
mailSender
的配置不变，添加一个实现
MimeMessagePreparator
的类
OneMimeMessagePreparator
，代码如下。
import
java.util.Date;
import
javax.activation.DataHandler;
import
javax.activation.FileDataSource;
import
javax.mail.Message;
import
javax.mail.Multipart;
import
javax.mail.internet.InternetAddress;
import
javax.mail.internet.MimeBodyPart;
import
javax.mail.internet.MimeMessage;
import
javax.mail.internet.MimeMultipart;
import
org.springframework.mail.javamail.MimeMessagePreparator;
public
class
OneMimeMessagePreparator
implements
MimeMessagePreparator{
public
void
prepare(MimeMessage mm)
throws
Exception {
mm.setRecipient(Message.RecipientType.
TO
,
new
InternetAddress(
"kafka0102@126.com"
));
mm.setFrom(
new
InternetAddress(
"kafka0102@126.com"
));
mm.setSubject(
"I
am you"
);
Multipart
mp =
new
MimeMultipart();
MimeBodyPart
mbp =
new
MimeBodyPart();
mbp.setText(
"hello
kafka0102"
);
mp.addBodyPart(mbp);
String[]
files =
new
String[]{
"/home/kafka0102/Document/
常用基础算法
.txt"
,
"/home/kafka0102/Document/21164.html"
};
for
(String
f : files){
MimeBodyPart
mbpFile =
new
MimeBodyPart();
FileDataSource
fds =
new
FileDataSource(f);
mbpFile.setDataHandler(
new
DataHandler(fds));
mbpFile.setFileName(fds.getName());
mp.addBodyPart(mbpFile);
}
mm.setContent(mp);
mm.setSentDate(
new
Date());
}
}
OneMimeMessagePreparator
的功能就是配置
MimeMessage
，其中添加了两个附件。下面就是简单的使用方法。
BeanFactory
bf = new
ClassPathXmlApplicationContext("service-applicationContext.xml");
JavaMailSender
ms = (JavaMailSender)bf.getBean("mailSender");
ms.send(new
OneMimeMessagePreparator());