源代码如下:

model层

package zlc.model;/***
* @author 信1705-1班赵路仓
* @version 1.0
*/public class Data {private double r;    //贴现率private double y;    //贴现因子private double rmb;    //现金public double getR() {return r;}public void setR(double r) {this.r = r;}public double getY() {return y;}public void setY(double y) {this.y = y;}public double getRmb() {return rmb;}public void setRmb(double rmb) {this.rmb = rmb;}}

view层

package zlc.view;/***
* @author 信1705-1班赵路仓
* @version 1.0
*/public class View {public void print(double sum) {System.out.println(sum);}}

Controller层

package zlc.controller;import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;import zlc.model.Data;
import zlc.view.View;/***
* @author 信1705-1班赵路仓
* @version 1.0
*/public class Controller {DecimalFormat format = new DecimalFormat("#.00");Scanner sc = new Scanner(System.in);private Data data;private View view;public Controller(Data data,View view) {this.data=data;this.view=view;}public static double formatDouble1(double d) {return (double)Math.round(d*10000)/10000;}//键盘输入数据public List<Data> Scin() {List<Data> datas =new ArrayList<Data>();try {System.out.println("请输入年数：");int x = sc.nextInt();System.out.println("请输入贴现率：");double y = sc.nextDouble();for(int i=0;i<=x;i++) {Data data=new Data();System.out.println("请输入第"+i+"年的盈亏金额：");double rmb = sc.nextDouble();data.setR(y);//贴现率data.setRmb(rmb);//本年金额data.setY(1/Math.pow((1+y), i));//,第一年的贴现因子是rmb本身，所以无需讨论初始投资年的情况System.out.println("第"+i+"年，"+"贴现率"+y+"贴现因子"+formatDouble1((1/Math.pow((1+y), i)))+"金额："+rmb+"计算后"+rmb*formatDouble1((1/Math.pow((1+y), i))));datas.add(data);}}catch(Exception e) {System.out.println("输入格式错误！");}return datas;}//计算净现值public double count() {List<Data> datas =new ArrayList<Data>();double sum = 0;datas=Scin();for(Data d:datas) {sum+=formatDouble1(d.getRmb())*formatDouble1(d.getY());//System.out.println(d.getRmb());//System.out.println(d.getY());//System.out.println(d.getRmb()*d.getY());//System.out.println("净现值为："+sum);}return sum;}public Data getData() {return data;}public void setData(Data data) {this.data = data;}public View getView() {return view;}public void setView(View view) {this.view = view;}}

Demo测试类

package demo;import zlc.controller.Controller;
import zlc.model.Data;
import zlc.view.View;public class Demo {public static void main(String[] args) {Data data=new Data();View view=new View();Controller controller=new Controller(data,view);System.out.println("程序开始");view.print(controller.count());System.out.println("程序结束");}
}

测试步骤：