阅读HTML文件并将其作为html格式的电子邮件发送

Question

我想阅读HTML文件，并希望发送HTML格式的电子邮件。

public class SendEmailer {

public void sendHtmlEmail(String host, String port,
        final String userName, final String password, String toAddress,
        String subject, String message) throws AddressException,
        MessagingException {

    final String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";
    // sets SMTP server properties
    Properties properties = new Properties();
    properties.setProperty("mail.smtp.socketFactory.class", SSL_FACTORY);
    properties.setProperty("mail.smtp.socketFactory.fallback", "false");
    properties.put("mail.smtp.host", host);
    properties.put("mail.smtp.port", port);
    properties.put("mail.smtp.auth", "true");
    properties.put("mail.smtp.starttls.enable", "true");
    properties.put("mail.store.protocol","pop3");
    properties.put("mail.transport.protocol","smtp");

    // creates a new session with an authenticator
    Authenticator auth = new Authenticator() {
        public PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(userName, password);
        }
    };

    Session session = Session.getInstance(properties, auth);

    // creates a new e-mail message
    Message msg = new MimeMessage(session);

    msg.setFrom(new InternetAddress(userName));
    InternetAddress[] toAddresses = { new InternetAddress(toAddress) };
    msg.setRecipients(Message.RecipientType.TO, toAddresses);
    msg.setSubject(subject);
    msg.setSentDate(new Date());
    // set plain text message
    msg.setContent(message, "text/html");

    // sends the e-mail
    Transport.send(msg);

}

 //Code to read HTML document. 
public void readHTML(String strfilename,String content){
   // content="";
    String str="";
    try{
        FileReader fr=new FileReader(strfilename);
        BufferedReader br=new BufferedReader(fr);

        while((str=br.readLine())!=null){
            System.out.println(str.toString());
            content+=str;
        }
        br.close();
    }catch(IOException ie){
        ie.printStackTrace();
    }

}


public static void main(String[] args) {
    // SMTP server information
    String host = "myhost.com";
    String port = "465";
    String mailFrom = "abc@myhost.com";
    String password = "abcd123";

    // outgoing message information
    String mailTo = "abc@gmail.com";
    String subject = "Test mail";

    // message contains HTML markups
    String message = "<i>Greetings!Sending HTML mail.</i><br>";
    message += "<font color=red>MyName</font>";


    SendEmailer mailer = new SendEmailer ();
    String filename="E:/filepath/filename.html"; 
    try {
        mailer.readHTML(filename);
        mailer.sendHtmlEmail(host, port, mailFrom, password, mailTo,
                subject, message);
        System.out.println("Email sent successfully.");
    } catch (Exception ex) {
        System.out.println("Failed to sent email.");
        ex.printStackTrace();
    }
}

}

我可以成功发送电子邮件。但现在我想发送html文件的完整正文部分。我写了一个方法readHTML()，但它没有读取该文件的内容，也没有发送相同的内容。它只发送我在消息变量中存储的内容。我在哪里弄错了？