LoanApplet类在引用其他包中的Loan类来创建Loan类对象时出错

Question

我在D盘根目录下创建了2个文件夹，分别是java和applet。
其中Loan类存放路径为D:\java\file，LoanApplet为D:\applet
Loan.java代码如下：
public class Loan{
private double annualInterestRate;
private int numberOfYears;
private double loanAmount;
private java.util.Date loanDate; public Loan(){
this(2.5, 1, 1000);
}
public Loan(double annualInterestRate,int numberOfYears,double loanAmount ){
this.annualInterestRate=annualInterestRate;
this.numberOfYears=numberOfYears;
this.loanAmount=loanAmount;
loanDate = new java.util.Date();
}
public double getAnnualInterestRate(){
return annualInterestRate;
}
public void setAnnualInterestRate(double annualInterestRate){
this.annualInterestRate=annualInterestRate;
}
public int getNumberOfYears(){
return numberOfYears;
}
public void setNumberOfYears(int numberOfYears){
this.numberOfYears=numberOfYears;
}
public double getLoanAmount(){
return loanAmount;
}
public void setLoanAmount(double loanAmount){
this.loanAmount=loanAmount;
}
public double monthlyPayment(){
double monthlyInterestRate=annualInterestRate/1200;
return loanAmount*monthlyInterestRate/(1 - (Math.pow(1/(1 + monthlyInterestRate),numberOfYears  * 12) ) );
}
public double totalPayment(){
return monthlyPayment() * numberOfYears * 12;
}
public java.util.Date getLoanDate(){
return loanDate;
}
}----------------------------------------------------------------------------
LoanApplet.java代码如下:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.TitledBorder;import file.Loan;//希望导入该类public class LoanApplet extends JApplet
implements ActionListener{
private JTextField jtfAnnualInterestRate = new JTextField();
private JTextField jtfNumberOfYears = new JTextField();
private JTextField jtfLoanAmount = new JTextField();
private JTextField jtfMonthlyPayment = new JTextField();
private JTextField jtfTotalPayment = new JTextField();

private JButton jbtComputeLoan = new JButton("Compute Payment");

public void init(){
jtfMonthlyPayment.setEditable(false);
jtfTotalPayment.setEditable(false);

jtfAnnualInterestRate.setHorizontalAlignment(JTextField.RIGHT);
jtfNumberOfYears.setHorizontalAlignment(JTextField.RIGHT);
jtfLoanAmount.setHorizontalAlignment(JTextField.RIGHT);
jtfMonthlyPayment.setHorizontalAlignment(JTextField.RIGHT);
jtfTotalPayment.setHorizontalAlignment(JTextField.RIGHT);

JPanel p1 = new JPanel();
p1.setLayout(new GridLayout(5, 2));
p1.add(new JLabel("Annual Interest Rate"));
p1.add(jtfAnnualInterestRate);
p1.add(new JLabel("Number of Years"));
p1.add(jtfNumberOfYears);
p1.add(new JLabel("Loan Amount"));
p1.add(jtfLoanAmount);
p1.add(new JLabel("Monthly Payment"));
p1.add(jtfMonthlyPayment);
p1.add(new JLabel("Total Payment"));
p1.add(jtfTotalPayment);
p1.setBorder(new TitledBorder("Enter interest rate, year and loan amount"));

JPanel p2 = new JPanel();
p2.setLayout(new FlowLayout(FlowLayout.RIGHT));
p2.add(jbtComputeLoan);

getContentPane().add(p1, BorderLayout.CENTER);
getContentPane().add(p2, BorderLayout.SOUTH);

jbtComputeLoan.addActionListener(this);
}

public void actionPerformed(ActionEvent e){
if(e.getSource() == jbtComputeLoan) {
double interest = Double.parseDouble(jtfAnnualInterestRate.getText());
int year = Integer.parseInt(jtfNumberOfYears.getText());
double loanAmount = Double.parseDouble(jtfLoanAmount.getText());
Loan loan = new Loan(interest, year, loanAmount);//创建Loan的一个实例                   jtfMonthlyPayment.setText("" + (int)(loan.monthlyPayment() * 100) / 100.0);
jtfTotalPayment.setText("" + (int)(loan.totalPayment() * 100) / 100.0);
}
}
}之前的环境变量配置成功，为了实现现在这个程序，在系统环境变量CLASSPATH中添加了D:\java;
CLASSPATH = .;D:\java;%JAVA_HOME%\lib;%JAVA_HOME%\lib\tools.jar;
我使用的是JDK1.6版本，LoanApplet是个applet，在命令提示符下的操作：
C:\Documents and Settings\Administrator>d:
D:\>cd applet
D:\applet>javac LoanApplet.java
结果显示：
LoanApplet.java:5: 无法访问 flie.Loan
错误的类文件:  D:\java\file\Loan.class
类文件包含错误的类： Loan
请删除该文件或确保该文件位于正确的类路径子目录中。弄了好久，实在搞不定，本人初学java，对这个包之间的引用也不怎么懂，请论坛里的高手们来教教我，谢谢了