用Java写PTA 7-11 设计一个能处理异常的Loan类

用Java写PTA 7-11 设计一个能处理异常的Loan类
定义一个贷款类Loan，其中有属性：
annualInterestRate:double，表示贷款的年利率（默认值：2.5）
numberOfYears:int，表示贷款的年数（默认值：1）
loanAmount:double,表示贷款额（默认值：100）
loanDate:java.util.Date,表示创建贷款的日期
定义方法：
（1）默认的无参构造方法
（2）带指定利率、年数和贷款额的构造方法
（3）所有属性的get/set方法
（4）返回这笔贷款的月支付额getMonthlyPayment()
月支付额 = (贷款额度月利率)/(1-(1/Math.pow(1+月利率,年数12)))
（5）返回这笔贷款的总支付额getTotalPayment()
总支付额度 = 月支付额度年数12

附上如下的测试类。

public class Main{
  public static void main(String[] args) {
      Scanner input = new Scanner(System.in);
      while (input.hasNext()) {
          double AIR = input.nextDouble();
          int NOY = input.nextInt();
          double LA = input.nextDouble();
          try {
              Loan m = new Loan(AIR, NOY, LA);
              System.out.printf("%.3f\n",m.getTotalPayment());
          } catch (Exception ex) {
              System.out.println(ex);
          }
      }
    
  }
}
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输入格式:
输入有多组数据，一个实数表示年利率，一个整数表示年数，一个实数表示贷款总额。

输出格式:
若任意一项小于或等于零，抛出IllegalArgumentException异常及相应描述（Number of years must be positive或Annual interest rate must be positive或Loan amount must be positive）；有多项不符合，以不符合最前项为准；

若均符合要求，按照格式输出总额。

输入样例:
在这里给出一组输入。例如：

1 1 1000
2.0 0 2000
0 0 0
输出样例:
在这里给出相应的输出。例如：

1005.425
java.lang.IllegalArgumentException: Number of years must be positive
java.lang.IllegalArgumentException: Annual interest rate must be positive

import java.util.Scanner;
class Loan{
  double annualInterestRate;
   int numberOfYears;
 double loanAmount;
java.util.Date loanDate;
    Loan(){
        this.annualInterestRate=2.5;
        this.numberOfYears=1;
        this.loanAmount=100;
        this.loanDate=loanDate;
    }
     Loan(double annualInterestRate,int numberOfYears,double loanAmount){
        this.annualInterestRate=annualInterestRate;
        this.numberOfYears=numberOfYears;
        this.loanAmount=loanAmount;
        
    }
    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 java.util.Date getLoanDate() {
	return loanDate;
}
public void setLoanDate(java.util.Date loanDate) {
	this.loanDate = loanDate;
}
  public double getMonthlyPayment(){
      double monthRate=annualInterestRate/1200;
      double monthlyPayment=(monthRate)/(1-(1/Math.pow(1+monthRate,numberOfYears*12)));  
      return monthlyPayment;
  }
 public double getTotalPayment(){
	 double totalPayment=getMonthlyPayment()*12*numberOfYears;
     return totalPayment;
 }

}
public class Main{
  public static void main(String[] args) {
      Scanner input = new Scanner(System.in);
      while (input.hasNext()) {
          double AIR = input.nextDouble();
          int NOY = input.nextInt();
          double LA = input.nextDouble();
          
          try {
              Loan m = new Loan(AIR, NOY, LA);
              if (AIR<=0)throw new IllegalArgumentException("Annual interest rate must be positive");
else if (NOY<=0)throw new IllegalArgumentException("Number of years must be positive");
else if (LA<=0)throw new IllegalArgumentException("Loan amount must be positive");

              System.out.printf("%.3f\n",m.getTotalPayment()*1000);
          } catch (Exception ex) {
              System.out.println(ex);
          }
      }
    
  }
}
        
        
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