1、目标

实现50万的存款目标，俗称 “50计划”。💪

private static int targetAmount = 500000;

2、时间

达成这个目标，我们将在第xxxx年xx月实现？⌛

答案：文末给出了结果。

3、因数

纳入考虑的可变因素💡，目前列举了7项：投资年化率、工资、收房租、年终奖、生活费、付房租、贷款月供。

不纳入考虑的因素：生病、意外事故、工资不固定的情况，此类不太适用，误差较大。

private static double yearRate = 0.10; //income private static int wages = 9200; private static int rentCollect = 0; private static int yearEndAward = 20000; //payout private static int livingCost = 800; private static int rent = 800; private static int monthlyPayment = 0;

4、达成

这是一个算法，通过修改7项可变因素，将会得出具有参考价值的数据。 计算的核心就是利用复利效应，充分发挥资金价值。😀

源代码如下：

import java.math.BigDecimal; import java.math.RoundingMode; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class Test { public static BigDecimal MONTHS_A_YEAR = new BigDecimal(12); public static BigDecimal MONTHS_TWO_YEAR = new BigDecimal(24); private static int targetAmount = 500000; private static double yearRate = 0.10; //income private static int wages = 9200; private static int rentCollect = 0; private static int yearEndAward = 20000; //payout private static int livingCost = 800; private static int rent = 800; private static int monthlyPayment = 0; private static List<Map<BigDecimal, BigDecimal>> yearAmountMap = new ArrayList<>(); private static List<Map<BigDecimal, BigDecimal>> monthAmountMap = new ArrayList<>(); public static void main(String[] args) { BigDecimal yearRemainIncome = getYearRemainIncome(); gotoAchieveGoals(yearRemainIncome); } private static BigDecimal getYearRemainIncome() { int remainWages = wages - livingCost - rent - monthlyPayment; BigDecimal remainWagesBd = new BigDecimal(remainWages); BigDecimal yearEndAwardBd = new BigDecimal(yearEndAward); BigDecimal rentCollectBd = new BigDecimal(rentCollect); BigDecimal yearWageBd = remainWagesBd.multiply(MONTHS_A_YEAR); BigDecimal yearRentBd = rentCollectBd.multiply(MONTHS_A_YEAR); BigDecimal yearWageAndRent = yearWageBd.add(yearRentBd); BigDecimal yearWageAndRentAndYearEndAward = yearWageAndRent.add(yearEndAwardBd); return yearWageAndRentAndYearEndAward; } private static void gotoAchieveGoals(BigDecimal yearRemainIncome) { yearAmountMap.clear(); BigDecimal targetAmount = new BigDecimal(Test.targetAmount); BigDecimal monthRemainIncome = yearRemainIncome.divide(MONTHS_A_YEAR, 2, BigDecimal.ROUND_HALF_UP); BigDecimal achieveGoalsTotalMonths = targetAmount.divide(monthRemainIncome, 2, BigDecimal.ROUND_HALF_UP); BigDecimal achieveGoalsTotalYears = achieveGoalsTotalMonths.divide(MONTHS_A_YEAR, 2, RoundingMode.HALF_UP); BigDecimal investmentAndPrincipalTotalAmount = getInvestmentAndPrincipalTotalAmount(yearRemainIncome, achieveGoalsTotalMonths); BigDecimal totalInvestmentIncomeAmount = investmentAndPrincipalTotalAmount.subtract(targetAmount); double achieveGoalsWhereYear = getAchieveGoalsWhereYear(); System.out.println("--------------Total Result--------------"); System.out.println(" A year fixed income : " + yearRemainIncome); System.out.println(" Total investment income : " + totalInvestmentIncomeAmount); System.out.println(" Total principal income : " + investmentAndPrincipalTotalAmount.subtract(totalInvestmentIncomeAmount)); System.out.println(" Total investment and principal income : " + investmentAndPrincipalTotalAmount); System.out.println(" Total year achieving target by fixed income : " + achieveGoalsTotalYears); System.out.println(" Total year achieving target by fixed and investment income : " + achieveGoalsWhereYear); } private static BigDecimal getInvestmentAndPrincipalTotalAmount(BigDecimal principal, BigDecimal achieveGoalsTotalMonths) { BigDecimal yearRateBd = new BigDecimal(yearRate); yearRateBd = yearRateBd.setScale(2, RoundingMode.HALF_UP); BigDecimal monthRate = yearRateBd.divide(MONTHS_TWO_YEAR, 6, BigDecimal.ROUND_HALF_UP); monthRate = monthRate.setScale(4, RoundingMode.HALF_UP); double yearAccumulateAmount = getYearAccumulateAmount(principal, achieveGoalsTotalMonths, yearRateBd); double yearRemainMonthAccumulateAmount = getYearRemainMonthAccumulateAmount(principal, new BigDecimal(yearAccumulateAmount), achieveGoalsTotalMonths, monthRate); BigDecimal accumulateAmountBd = new BigDecimal(yearAccumulateAmount + yearRemainMonthAccumulateAmount); accumulateAmountBd = accumulateAmountBd.setScale(2, RoundingMode.HALF_UP); return accumulateAmountBd; } private static double getYearAccumulateAmount(BigDecimal principal, BigDecimal totalMonths, BigDecimal yearRate) { System.out.println("--------------year_rate（" + yearRate + "）--------------"); int year = totalMonths.setScale(0, RoundingMode.HALF_UP).intValue() / 12; BigDecimal yearAccumulateAmount = new BigDecimal(0); BigDecimal investmentAndPrincipalAmount; for (int i = 1; i <= year; i++) { if (i == 1) { investmentAndPrincipalAmount = principal; } else { investmentAndPrincipalAmount = yearAccumulateAmount; } BigDecimal yearInvestmentIncome = investmentAndPrincipalAmount.multiply(yearRate).setScale(2, RoundingMode.HALF_UP); yearAccumulateAmount = yearAccumulateAmount.add(principal.add(yearInvestmentIncome)); System.out.println("The " + i + " year, yearAccumulateAmount - yearInvestmentIncome = " + yearAccumulateAmount + " - " + yearInvestmentIncome + " = " + (yearAccumulateAmount.subtract(yearInvestmentIncome).doubleValue())); HashMap<BigDecimal, BigDecimal> map = new HashMap<>(); map.put(BigDecimal.valueOf(i), yearAccumulateAmount); yearAmountMap.add(map); } return yearAccumulateAmount.doubleValue(); } private static double getYearRemainMonthAccumulateAmount(BigDecimal principal, BigDecimal originYearAccumulateAmount, BigDecimal achieveGoalsTotalMonths, BigDecimal monthRate) { System.out.println("--------------remain_month_rate（" + monthRate + "）--------------"); BigDecimal monthFixedIncome = principal.divide(MONTHS_A_YEAR, 2, RoundingMode.HALF_UP); int remainMonths = achieveGoalsTotalMonths.intValue() % 12; BigDecimal yearAccumulateAmountBd = originYearAccumulateAmount; yearAccumulateAmountBd = yearAccumulateAmountBd.setScale(2, RoundingMode.HALF_UP); BigDecimal targetYearAccumulateAmount = yearAccumulateAmountBd; BigDecimal yearRemainMonthAccumulateAmount; for (int i = 1; i <= remainMonths; i++) { yearRemainMonthAccumulateAmount = targetYearAccumulateAmount; yearRemainMonthAccumulateAmount = yearRemainMonthAccumulateAmount.setScale(2, RoundingMode.HALF_UP); BigDecimal monthInvestmentIncome = yearRemainMonthAccumulateAmount.multiply(monthRate).setScale(2, RoundingMode.HALF_UP); BigDecimal fixedInvestmentIncome = (monthFixedIncome.add(monthInvestmentIncome)); targetYearAccumulateAmount = targetYearAccumulateAmount.add(fixedInvestmentIncome); System.out.println("The remain month" + i + " ," + " targetYearAccumulateAmount - monthInvestmentIncome = " + " " + targetYearAccumulateAmount + " - " + monthInvestmentIncome + " = " + (targetYearAccumulateAmount.subtract(monthInvestmentIncome).doubleValue())); HashMap<BigDecimal, BigDecimal> map = new HashMap<>(); map.put(BigDecimal.valueOf(i), targetYearAccumulateAmount); monthAmountMap.add(map); } return targetYearAccumulateAmount.subtract(yearAccumulateAmountBd).doubleValue(); } public static double getAchieveGoalsWhereYear() { BigDecimal targetAmountBd = new BigDecimal(targetAmount); targetAmountBd = targetAmountBd.setScale(2, RoundingMode.HALF_UP); double totalYear = yearAmountMap.size(); for (Map<BigDecimal, BigDecimal> map : yearAmountMap) { for (Map.Entry<BigDecimal, BigDecimal> entry : map.entrySet()) { if (entry.getValue().compareTo(targetAmountBd) >= 0) { return entry.getKey().doubleValue(); } } } //year amount is not enough,so find the month for (Map<BigDecimal, BigDecimal> map : monthAmountMap) { for (Map.Entry<BigDecimal, BigDecimal> entry : map.entrySet()) { if (entry.getValue().compareTo(targetAmountBd) >= 0) { return totalYear + (entry.getKey().divide(MONTHS_A_YEAR, 2, RoundingMode.HALF_UP)).doubleValue(); } } } double month = BigDecimal.valueOf(monthAmountMap.size()).divide(MONTHS_A_YEAR, 2, RoundingMode.HALF_UP).doubleValue(); return totalYear + month; } }

输出：

--------------year_rate（0.10）-------------- The 1 year, totalIncome - investmentIncomeBd = 122320.00 - 11120.00 = 111200.0 The 2 year, totalIncome - investmentIncomeBd = 245752.00 - 12232.00 = 233520.0 The 3 year, totalIncome - investmentIncomeBd = 381527.20 - 24575.20 = 356952.0 The 4 year, totalIncome - investmentIncomeBd = 530879.92 - 38152.72 = 492727.2 --------------remain_month_rate（0.0042）-------------- The remain month1 , totalIncome - investmentIncomeBd = 542376.29 - 2229.70 = 540146.59 The remain month2 , totalIncome - investmentIncomeBd = 553920.94 - 2277.98 = 551642.96 The remain month3 , totalIncome - investmentIncomeBd = 565514.08 - 2326.47 = 563187.61 The remain month4 , totalIncome - investmentIncomeBd = 577155.91 - 2375.16 = 574780.75 The remain month5 , totalIncome - investmentIncomeBd = 588846.63 - 2424.05 = 586422.58 --------------Total Result-------------- A year fixed income : 111200 Total investment income : 88846.63 Total principal income : 500000.00 Total investment and principal income : 588846.63 Total year achieving target by fixed income : 4.50 Total year achieving target by fixed and investment income : 4.0

111200：一年能攒下的金额；

88846.63：投资收入总金额；

4.50：只拿固定工资不投资需要4年半才能达成目标；

4.0：通过固定工资和投资理财则只需要4年即可达成目标；

😎要不要去看看自己的情况，那就去编译源码，修改7项可变因素吧。

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