Java 设计一个贷款计算器 简易

             1
            import javax.swing.*;
 2import java.awt.*;
 3import java.awt.event.*;
 4import javax.swing.border.*;
 5 6publicclass LoanCalculator extends JFrame {
 7privateclass ButtonListener implements ActionListener {
 8        @Override
 9publicvoid actionPerformed(ActionEvent e) {
10// TODO Auto-generated method stub11double interest=
12                    Double.parseDouble(jtfAnnualInterestRate.getText());
13int year=
14                    Integer.parseInt(jtfNumberOfYears.getText());
15double loanAmount=
16                    Double.parseDouble(jtfLoanAmount.getText());
1718double monthlyInterest=interest/1200;
19double monthlyPayment= loanAmount*monthlyInterest/(1-1/Math.pow(1+monthlyInterest, 
20                     year*12));
21double totalPayment=monthlyPayment*year*12;
2223             jtfMonthlyPayment.setText(String.format("%.2f", monthlyPayment));
24             jtfTotalPayment.setText(String.format("%.2f", totalPayment));
25        }
26    }
2728private JTextField jtfAnnualInterestRate=new JTextField();
29private JTextField jtfNumberOfYears=new JTextField();
30private JTextField jtfLoanAmount=new JTextField();
31private JTextField jtfMonthlyPayment=new JTextField();
32private JTextField jtfTotalPayment=new JTextField();
3334private JButton jbtComputeLoan=new JButton("Compute Payment");
3536public LoanCalculator(){
37         JPanel p1=new JPanel(new GridLayout(5,2));
38         p1.add(new JLabel("Annual Interest Rate"));
39        p1.add(jtfAnnualInterestRate);
40         p1.add(new JLabel("Number of Years"));
41        p1.add(jtfNumberOfYears);
42         p1.add(new JLabel("Loan Amount"));
43        p1.add(jtfLoanAmount);
44         p1.add(new JLabel("Monthly Payment"));
45        p1.add(jtfMonthlyPayment);
46         p1.add(new JLabel("Total Payment"));
47        p1.add(jtfTotalPayment);
48         p1.setBorder(new TitledBorder("Enter loan amount, interest rate,"
49                 + " and year"));
5051         JPanel p2=new JPanel(new FlowLayout(FlowLayout.RIGHT));
52        p2.add(jbtComputeLoan);
53        add(p1,BorderLayout.CENTER);
54        add(p2,BorderLayout.SOUTH);
55         jbtComputeLoan.addActionListener(new ButtonListener());
5657    }
5859publicstaticvoid main(String[] args) {
60// TODO Auto-generated method stub61         LoanCalculator frame=new LoanCalculator();
62         frame.setTitle("LoanCalculator");
63        frame.pack();
64         frame.setLocationRelativeTo(null);
65        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
66         frame.setVisible(true);
67    }
6869 }