16.5

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

public class Test_16_5 extends JFrame{
    private JTextField JT1 = new JTextField();
    private JTextField JT2 = new JTextField();
    private JTextField JT3 = new JTextField();
    private JTextField JT4 = new JTextField();
    private JLabel JL1 = new JLabel("investmentAmount");
    private JLabel JL2 = new JLabel("years");
    private JLabel JL3 = new JLabel("monthlyInterestRate");
    private JLabel JL4 = new JLabel("Future Value");
    private JButton JB = new JButton("Calculate");
    
    public Test_16_5(){
        JPanel JP1 = new JPanel(new GridLayout(4,2));
        JPanel JP2 = new JPanel(new FlowLayout(FlowLayout.RIGHT));
        
        
        JP1.add(JL1);JP1.add(JT1);
        JP1.add(JL2);JP1.add(JT2);
        JP1.add(JL3);JP1.add(JT3);
        JP1.add(JL4);JP1.add(JT4);
        
        JP2.add(JB);
        add(JP1,BorderLayout.CENTER);
        add(JP2,BorderLayout.SOUTH);
        
        JB.addActionListener(new ComputeListener());
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Test_16_5 T1 = new Test_16_5();
        T1.setTitle("Test_16.5");
        T1.pack();
        T1.setLocationRelativeTo(null);
        T1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        T1.setVisible(true);
    }

    class ComputeListener implements ActionListener{    
        
        @Override
        public void actionPerformed(ActionEvent e) {
            // TODO Auto-generated method stub
            double investmentAmount = Double.parseDouble(JT1.getText());
            int years = Integer.parseInt(JT2.getText());
            double monthlyInterestRate = Double.parseDouble(JT3.getText());
            Interests interes = new Interests(investmentAmount,monthlyInterestRate,years);
            JT4.setText(interes.getFutureValue()+"");
        }        
    }
    class Interests{
        private double inves;
        private double monthly;
        private int year;
        public Interests(double inves,double monthly,int year){
            this.inves = inves;
            this.year = year;
            this.monthly = monthly;
        }
        public double getFutureValue(){
            return inves*Math.pow(1+monthly, year*12);
        }
    }
    
}

效果图：