Session
Session用于收集JavaMail运行过程中的环境信息，它可以创建一个单例的对象，也可以每次创建新的对象，Session没有构造器，只能通过如下方法创造实例：
getDefaultInstance得到的始终是该方法初次创建的缺省的对象，而getInstance得到的始终是新的对象，Authenticator的使用后面会说到。通过Session可以创建Transport(用于发送邮件)和Store(用于接收邮件)，Transport和Store是JavaMail API中定义好的接口，通过上文我们知道JavaMail分为API和service provider两部分，API定义了相关接口(eg.:Transport and Store)，service provider中实现了这些接口，这些实现类配置在名为
javamail.providers或
javamail.default.providers的文件中，该文件放在mail.jar/smtp.jar/pop3.jar/imap.jar中的META-INF下，文件内容格式如：
static Session |
getDefaultInstance(Properties props)Get the default Session object. |
static Session |
getDefaultInstance(Properties props,Authenticator authenticator)Get the default Session object. |
static Session |
getInstance(Properties props)Get a new Session object. |
static Session |
getInstance(Properties props,Authenticator authenticator)Get a new Session object. |
# JavaMail IMAP provider Sun Microsystems, Inc
protocol=imap; type=store; class=com.sun.mail.imap.IMAPStore; vendor=Sun Microsystems, Inc;
protocol=imaps; type=store; class=com.sun.mail.imap.IMAPSSLStore; vendor=Sun Microsystems, Inc;
# JavaMail SMTP provider Sun Microsystems, Inc
protocol=smtp; type=transport; class=com.sun.mail.smtp.SMTPTransport; vendor=Sun Microsystems, Inc;
protocol=smtps; type=transport; class=com.sun.mail.smtp.SMTPSSLTransport; vendor=Sun Microsystems, Inc;
# JavaMail POP3 provider Sun Microsystems, Inc
protocol=pop3; type=store; class=com.sun.mail.pop3.POP3Store; vendor=Sun Microsystems, Inc;
protocol=pop3s; type=store; class=com.sun.mail.pop3.POP3SSLStore; vendor=Sun Microsystems, Inc; Store |
getStore()Get a Store object that implements this user's desired Store protocol. |
Store |
getStore(Provider provider)Get an instance of the store specified by Provider. |
Store |
getStore(String protocol)Get a Store object that implements the specified protocol. |
Store |
getStore(URLName url)Get a Store object for the given URLName. |
Transport |
getTransport()Get a Transport object that implements this user's desired Transport protcol. |
Transport |
getTransport(Address address)Get a Transport object that can transport a Message of the specified address type. |
Transport |
getTransport(Provider provider)Get an instance of the transport specified in the Provider. |
Transport |
getTransport(String protocol)Get a Transport object that implements the specified protocol. |
Transport |
getTransport(URLName url)Get a Transport object for the given URLName. |
Message
Message是邮件的载体，用于封装邮件的所有信息，Message是一个抽象类，已知的实现类有MimeMessage。一封完整的邮件都有哪些信息呢？我们打开一个邮件客户端，我用的是FoxMail，新建一封邮件，如下图所示：
这就是一封完整的邮件包含的所有信息，默认情况下是没有暗送和回复设置的，可以通过菜单栏-->查看-->暗送地址/回复地址来显示出来，回复地址默认情况下为发件人，暗送是比较猥琐的发邮件方式，暗送邮件除了被暗送者，没有人能知道暗送给谁了，邮件头信息中也不会记录。下面来看下Message中设置邮件信息的一些方法。
发件人
abstract void |
setFrom()Set the "From" attribute in this Message. |
abstract void |
setFrom(Address address)Set the "From" attribute in this Message. |
收件人/抄送人/暗送人
void |
setRecipient(Message.RecipientType type,Address address)Set the recipient address. |
abstract void |
setRecipients(Message.RecipientType type,Address[] addresses)Set the recipient addresses. |
static Message.RecipientType |
BCCThe "Bcc" (blind carbon copy) recipients. |
static Message.RecipientType |
CCThe "Cc" (carbon copy) recipients. |
static Message.RecipientType |
TOThe "To" (primary) recipients. |
回复人
void |
setReplyTo(Address[] addresses)Set the addresses to which replies should be directed. |
标题
abstract void |
setSubject(String subject)Set the subject of this message. |
内容
void |
setContent(Multipart mp)This method sets the given Multipart object as this message's content. |
void |
setContent(Object obj,String type)A convenience method for setting this part's content. |
void |
setText(String text)A convenience method that sets the given String as this part's content with a MIME type of "text/plain". |