我想将主方法转换为新的非主方法类

Question

I have a program that I can send emails through. However, this needs to be a part of a much bigger program. The Email class is under a different package whereas my other 2 classes (The driver class/main program, as well as another object class) are both in the default package. Can I access the email class despite it being in a different package or do I need them all to be in one package? And how do I go about doing either of these? Currently, I tried removing the main method part of the email class and putting it in the default package with my driver class, this resulted in many syntax errors. Below are some photos showing my classes and some code. The SendMail class is the same as SendMailTLS just with the main method being removed and put into the default package. The SendMailTLS class works perfectly, I just need to be able to access it from the IA class.

SendMail Class:

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SendMail {


        final String username = "treybyroncollier@gmail.com";
        final String password = "13october";

        Properties props = new Properties();
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.port", "587");

        Session session = Session.getInstance(props,
          new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
          });

        try {

            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("treybyroncollier@gmail.com"));
            message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse("treycollier@live.co.uk"));
            message.setSubject("THIS EMAIL IS A TEST");
            message.setText("Hello Trey, just to let you know that this email is a test and everything is working with Java.");

            Transport.send(message);

            System.out.println("Done");

        } catch (MessagingException e) {
            throw new RuntimeException(e);
        }
}

SendMailTLS Class:

package com.mkyong.common;

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SendMailTLS {

    public static void main(String[] args) {

        final String username = "treybyroncollier@gmail.com";
        final String password = "13october";

        Properties props = new Properties();
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.port", "587");

        Session session = Session.getInstance(props,
          new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
          });

        try {

            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("treybyroncollier@gmail.com"));
            message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse("treycollier@live.co.uk"));
            message.setSubject("THIS EMAIL IS A TEST");
            message.setText("Hello Trey, just to let you know that this email is a test and everything is working with Java.");

            Transport.send(message);

            System.out.println("Done");

        } catch (MessagingException e) {
            throw new RuntimeException(e);
        }
    }
}

Answer 1

You should learn the basics first and then start with such a comlicated program.

In your sendMail class, you added all of your code directly into the class body, that's not going to work. Instead, create a method in that class and paste your code in there.

Then you can call that method from your other class after you imported the package.

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

    public class SendMail {

        public static void start() {

            final String username = "treybyroncollier@gmail.com";
            final String password = "13october";

            Properties props = new Properties();
            props.put("mail.smtp.auth", "true");
            props.put("mail.smtp.starttls.enable", "true");
            props.put("mail.smtp.host", "smtp.gmail.com");
            props.put("mail.smtp.port", "587");

            Session session = Session.getInstance(props,
              new javax.mail.Authenticator() {
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(username, password);
                }
              });

            try {

                Message message = new MimeMessage(session);
                message.setFrom(new InternetAddress("treybyroncollier@gmail.com"));
                message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse("treycollier@live.co.uk"));
                message.setSubject("THIS EMAIL IS A TEST");
                message.setText("Hello Trey, just to let you know that this email is a test and everything is working with Java.");

                Transport.send(message);

                System.out.println("Done");

            } catch (MessagingException e) {
                throw new RuntimeException(e);
            }
        }
    }

You can then run that code from your new main method or any other method you like.

public class YourMainClass {

    public static void main(String[] args) {
        SendMail.start();
    }
}

In short, if you don't want your main method to execute when you start the program, just change its name from main to something of your choice and remove the parameter String[] args .