groovyとjavamailでHTMLメールを送る

groovyとjavamailでHTMLメールを送るには、以下のコードを実行します。

@Grab(group="javax.mail", module="mail", version="latest.integration")
import java.security.*
import java.util.*
import javax.mail.*
import javax.mail.internet.*
import groovy.xml.*

smtpHost = "smtp.gmail.com"
smtpPort = "465"
Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider())
Properties props = new Properties()
props.put("mail.smtp.host", smtpHost)
props.put("mail.smtp.port", smtpPort)
props.put("mail.smtp.auth", "true")
props.put("mail.smtp.socketFactory.port", smtpPort);
props.put("mail.smtp.socketFactory.class",
  "javax.net.ssl.SSLSocketFactory")
props.put("mail.smtp.socketFactory.fallback", "false")

Session session = Session.getDefaultInstance(props,
  [
    getPasswordAuthentication: {
      return new PasswordAuthentication("youraccount@gmail.com",
        'yourpassword')
    }
  ] as Authenticator
)
Message msg = new MimeMessage(session)
msg.setFrom(new InternetAddress(
  "youraccount@gmail.com","youraccount@gmail.com","iso-2022-jp"))
msg.setRecipients(Message.RecipientType.TO, "recipients@gmail.com")

msg.setSubject("HTMLメールサンプル","iso-2022-jp")
import groovy.xml.*
def writer = new StringWriter()
def html = new MarkupBuilder(writer)
html.doubleQuotes = true
html.html {
  body {
    p {
      mkp.yield("HTMLメールサンプル")
      br()
      a(href:"http://groovyarekore.blogspot.com", "groovyあれこれ")
    }
  }
}
msg.setContent(writer.toString(), "text/html; charset=iso-2022-jp")
Transport.send(msg)

動作環境
groovy 1.8.0, JDK6 Update22