一个web页面下的发信组件，只能发送文本和html格式的邮件，支持二次开发。-a web page letter under the components, can only send text and html format of the mail, the development of secondary support.

利用JavaMail发送邮件，包括纯文本邮件，Html格式邮件，和带附件的邮件-use JavaMail to send mail,include text mail,html mail and with attachs mail