interestcalculator.java

适合与JAVA初级程序员 适合JAVA初学者编程

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;

public class InterestCalculator extends JFrame
{

     private JLabel principalJLabel;
     private JTextField principalJTextField;
     private JLabel interestRateJLabel;
     private JTextField interestRateJTextField;
     private JLabel yearsJLabel;
     private JSpinner yearsJSpinner;
     private JLabel yearlyBalanceJLabel;
     private JTextArea yearlyBalanceJTextArea;
     private JScrollPane yearlyBalanceJScrollPane;
     private JButton calculateJButton;

     public InterestCalculator()
     {

         createUserInterface();
      }

     private void createUserInterface()
     {

         Container contentPane = getContentPane();
         contentPane.setLayout(null);

         principalJLabel = new JLabel();
         principalJLabel.setBounds(16,16,56,24);
         principalJLabel.setText("Principal:");
         contentPane.add(principalJLabel);
 
         principalJTextField = new JTextField();
         principalJTextField.setBounds(100,16,100,24);
         principalJTextField.setHorizontalAlignment(JTextField.RIGHT);
         contentPane.add(principalJTextField);

         interestRateJLabel = new JLabel();
         interestRateJLabel.setBounds(16,56,80,24);
         interestRateJLabel.setText("Interest rate:");
         contentPane.add(interestRateJLabel);

         interestRateJTextField = new JTextField();
         interestRateJTextField.setBounds(100,56,100,24);
         interestRateJTextField.setHorizontalAlignment(JTextField.RIGHT);
         contentPane.add(interestRateJTextField);
 
         yearsJLabel = new JLabel();
         yearsJLabel.setBounds(16,96,48,24);
         yearsJLabel.setText("Years:");
         contentPane.add(yearsJLabel);

         yearsJSpinner = new JSpinner(new SpinnerNumberModel(1,1,10,1));
         yearsJSpinner.setBounds(100,96,100,24);
         contentPane.add(yearsJSpinner);

         yearlyBalanceJLabel = new JLabel();
         yearlyBalanceJLabel.setBounds(16,136,150,24);
         yearlyBalanceJLabel.setText("Yearly account balance:");
         contentPane.add(yearlyBalanceJLabel);

         yearlyBalanceJTextArea = new JTextArea();
         yearlyBalanceJTextArea.setEditable(false);
         yearlyBalanceJScrollPane = new JScrollPane(yearlyBalanceJTextArea);
         yearlyBalanceJScrollPane.setBounds(16,160,300,92);
         contentPane.add(yearlyBalanceJScrollPane);
         
         calculateJButton = new JButton();
         calculateJButton.setBounds(216,16,100,24);
         calculateJButton.setText("Calculate");
         contentPane.add(calculateJButton);
         calculateJButton.addActionListener(

            new ActionListener()
            {
 
                public void actionPerformed(ActionEvent event)
                {

                     calculateJButtonActionPerformed(event);
                }

             }

         );

         setTitle("Interset Calculator");
         setSize(340,296);
         setVisible(true);

         }

         private void calculateJButtonActionPerformed(ActionEvent event)
         {

             double principal = Double.parseDouble(principalJTextField.getText());
             double rate = Double.parseDouble(interestRateJTextField.getText());
             
             Integer integerObject = (Integer)yearsJSpinner.getValue();
             int year = integerObject.intValue();
             
             yearlyBalanceJTextArea.setText("Year\tAmount on Deposit");
             DecimalFormat dollars = new DecimalFormat("$0.00");
             
             for(int count = 1; count <= year; count++)
             {

                 double amount = principal * Math.pow((1 + rate / 100),count);
                 yearlyBalanceJTextArea.append("\n" + count + "\t" + dollars.format
                                (amount));

              }

          }

          public static void main(String[]args)
          {

                 InterestCalculator application = new InterestCalculator();
                 application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

           }

}