您如何在Java应用程序中包含小程序？

Question

So for my computer science class we have to make a gpa calculator and include an applet in the same program to display the full name of the student and their GPA. I have the program working

import java.util.*;
import java.text.DecimalFormat;
import javax.swing.JApplet;
import java.awt.*;


public class Project1_Michael_Micool extends JApplet
{
public static void main(String[]args)
{
String first_name, last_name, course1, course2, course3, course4; 
    //Sets all the needed variables to string values for first, last and course names
int cred_course1, cred_course2, cred_course3, cred_course4, total_credits;
    //Sets all the course credits as int values
float grade_course1, grade_course2, grade_course3, grade_course4, grade_point1, grade_point2, grade_point3, grade_point4, total_grades_added, gpa;


Scanner scan = new Scanner(System.in);
DecimalFormat fmt = new DecimalFormat("0.##");


System.out.println("Welcome to the UNG GPA calculator.");

System.out.println();
System.out.println("Please enter your first name");
first_name = scan.next(); //Assigns the entered name as first_name
System.out.println("Please enter your last name");
last_name = scan.next();  //Assigns the entered name as last_name 


System.out.println();
System.out.println("A: 4.0      A-:3.67    ");
System.out.println("B+:3.33     B:3.00    B-:2.67");
System.out.println("C+: 2.33    C:2.00    C-:1.67");
System.out.println("D+: 1.33    D:1.00    F:0.00");


System.out.println();
System.out.println("Please enter your first course name and number. EX: PSYC1101");
course1 = scan.next();
System.out.println("Please enter the number of credits for course 1.");
cred_course1 = scan.nextInt();
System.out.println("Please enter your grade for course 1 using the chart. EX: B+= 3.33");
grade_course1 = scan.nextFloat();    


System.out.println();
System.out.println();
System.out.println("Please enter your second course name and number. EX: PSYC1101");
course2 = scan.next();
System.out.println("Please enter the number of credits for course 2.");
cred_course2 = scan.nextInt();
System.out.println("Please enter your grade for course 2 using the chart. EX: B+= 3.33");
grade_course2 = scan.nextFloat();


System.out.println();
System.out.println();
System.out.println("Please enter your third course name and number. EX: PSYC1101");
course3 = scan.next();
System.out.println("Please enter the number of credits for course 3.");
cred_course3 = scan.nextInt();
System.out.println("Please enter your grade for course 3 using the chart. EX: B+= 3.33");
grade_course3 = scan.nextFloat();


System.out.println();
System.out.println();
System.out.println("Please enter your fourth course name and number. EX: PSYC1101");
course4 = scan.next();
System.out.println("Please enter the number of credits for course 4.");
cred_course4 = scan.nextInt();
System.out.println("Please enter your grade for course 4 using the chart. EX: B+= 3.33");
grade_course4 = scan.nextFloat();


total_credits = cred_course1 + cred_course2 + cred_course3 + cred_course4; 
grade_point1 = grade_course1 * cred_course1; 
grade_point2 = grade_course2 * cred_course2;
grade_point3 = grade_course3 * cred_course3;
grade_point4 = grade_course4 * cred_course4;
total_grades_added = grade_point1 + grade_point2 + grade_point3 + grade_point4;
gpa = total_grades_added / total_credits;
gpa = Math.abs(gpa);


course1 = course1.toUpperCase();
course2 = course2.toUpperCase();
course3 = course3.toUpperCase();
course4 = course4.toUpperCase();


System.out.println("Your name is " + first_name + " " + last_name); 
System.out.println("You are taking " + course1 + " which is worth " + cred_course1 + " credit hours");
System.out.println("You are taking " + course2 + " which is worth " + cred_course2 + " credit hours");
System.out.println("You are taking " + course3 + " which is worth " + cred_course3 + " credit hours");
System.out.println("You are taking " + course4 + " which is worth " + cred_course4 + " credit hours");
System.out.println("Your total credit hours is " + total_credits);
System.out.println("Your GPA is " + fmt.format(gpa));
}
}

Here is the applet that I think should work.

public void paint(Graphics page)
{
page.drawString(first_name + " " + last_name, 110, 70);
page.drawString(gmt.format(gpa), 130, 100);
}

So my question is, how to you incorporate the applet into the program?

Answer 1

What you posted is not an "Applet"; it's just the paint method of something that might be an AWT widget (eg an applet). Just use that method in a widget that you integrate into your UI.

Answer 2

An Applet (or JApplet ) would not typically have a main(String[]) unless it is an hybrid application/applet (where the application is based around a Frame or JFrame ), but that main method is focused on the command line.

There is no practical way to use the command line code in either an applet or an application. It needs to be rewritten to use a GUI.

---

..for my computer science class..

Please refer the instructor to Why CS teachers should stop teaching Java applets .