模拟贷款系统，根据输入的贷款年利率、贷款年限和货款总额，计算等额本息情况下的月均还款额和总还款额并输出。

模拟贷款系统通常用于演示金融计算器的功能，其中包含计算每月偿还本金和利息的过程。等额本息还款法（也称为固定月供）是最常见的贷款还款方式之一，每个月偿还金额相等。下面是使用Java编写的简单示例，计算等额本息还款的月均还款额和总还款额：

import java.util.Scanner;

public class LoanCalculator {
    private static final double MONTHS_IN_YEAR = 12;
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("请输入贷款总额:");
        double loanAmount = scanner.nextDouble();
        
        System.out.println("请输入贷款年利率(小数形式):");
        double annualInterestRate = scanner.nextDouble() / 100; // 将百分比转换为小数
        
        System.out.println("请输入贷款年限(年):");
        int loanTermYears = scanner.nextInt();
        
        double totalPayments = calculateTotalPayments(loanAmount, annualInterestRate, loanTermYears * MONTHS_IN_YEAR);
        double monthlyPayment = calculateMonthlyPayment(loanAmount, annualInterestRate, loanTermYears * MONTHS_IN_YEAR);
        
        System.out.printf("每月还款额: %.2f\n", monthlyPayment);
        System.out.printf("总还款额: %.2f\n", totalPayments);
    }

    // 计算总还款额
    private static double calculateTotalPayments(double loanAmount, double interestRate, int loanMonths) {
        return loanAmount * (interestRate * Math.pow((1 + interestRate), loanMonths)) / ((Math.pow((1 + interestRate), loanMonths)) - 1);
    }
    
    // 计算每月还款额
    private static double calculateMonthlyPayment(double loanAmount, double interestRate, int loanMonths) {
        double monthlyInterestRate = interestRate / MONTHS_IN_YEAR;
        return (loanAmount * monthlyInterestRate) / (1 - Math.pow((1 - monthlyInterestRate), loanMonths));
    }
}

在这个程序中，`calculateTotalPayments`函数使用了贷款的本金、年利率和总月份数来计算总还款额，而`calculateMonthlyPayment`函数则利用月利率和贷款期数来计算每月应还金额。