某呗分期还款模拟

/**
 * 某呗计息还款规则说明实现
 * 
 * @return
 */
package jdongtech.jiebaiUtils;

import java.util.Arrays;
import java.util.Calendar;
import java.util.HashMap;
import java.util.Map;

import jdongtech.interestUtils.AverageCapitalPlusInterestUtils;

public class normalRepay {
	public static void main(String[] args) {
		// 需要手动填写
		double invest = 120; // 本金
		int month = 6;     // 期数
		double yearRate = 14.4 / 100; // 年利率
		int acctOffsetDay = 15;
		int accountDay = 13;     // 账单日，蚂蚁会把账单日设置成借款当日
		// 发起借款当天
		Calendar lendDay = Calendar.getInstance();
		lendDay.set(Calendar.MONTH, 4);
		lendDay.set(Calendar.DAY_OF_MONTH, 13);

		double dateRate = yearRate / 360;
		int[] daysCount = new int[month];
		int IncreaseFlag = 0;
		Calendar lendCalOffset = (Calendar) lendDay.clone();
		lendCalOffset.add(Calendar.DATE, acctOffsetDay);
		Calendar accCal = (Calendar) lendDay.clone();
		accCal.set(Calendar.DAY_OF_MONTH, accountDay);
		Calendar accCalBegin = (Calendar) accCal.clone();
		if (lendCalOffset.before(accCal)) {
		} else {
			accCalBegin.add(Calendar.MONTH, 1);
			IncreaseFlag = 1;
		}
		Calendar accCalEnd = (Calendar) accCal.clone();
		accCalEnd.add(Calendar.MONTH, month-1);

		System.out.println(lendDay.getTime() + "借款日期");
		System.out.println(accCalBegin.getTime() + "开始");
		System.out.println(accCalEnd.getTime() + "结束");
		int daysLending = RepayUtils.daysOffset(lendDay, accCalEnd);
		System.out.println("借款经历" + daysLending + "天");

		Calendar accCalPerEnd = (Calendar) accCalBegin.clone();
		for (int i = 0; i < month; i++) {
			Calendar accCalPerBeg;
			if (i == 0) {
				accCalPerBeg = (Calendar) lendDay.clone();
			} else {
				accCalPerBeg = (Calendar) accCalPerEnd.clone();
				accCalPerBeg.add(Calendar.MONTH, -1);
			}

			int daysPer = RepayUtils.daysOffset(accCalPerBeg, accCalPerEnd);
			daysCount[i] = daysPer;
			accCalPerEnd.add(Calendar.MONTH, 1);
		}
		//dateRate=0.0003;
		getPerMonthPrincipalInterestBig(invest, dateRate, month, daysCount, IncreaseFlag);
	}

	/**
	 * 计算实际等额本息每月额度
	 * 
	 * @return
	 */
	public static double getPerMonthPrincipalInterestBig(double invest, double dateRate, int totalmonth, int[] daysCount,
			int IncreaseFlag) {
		IncreaseFlag = 1;
		double perMonthStandard = AverageCapitalPlusInterestUtils.getPerMonthPrincipalInterest(invest, dateRate * 360,
				totalmonth);

		double perMonthMax = perMonthStandard * 1.1;
		double[] PRperMonth = new double[totalmonth];
		double[] PperMonth = new double[totalmonth];
		double[] RperMonth = new double[totalmonth];
		double[] PLeftperMonth = new double[totalmonth];
		Map<Double, Double> lastCheckMap = new HashMap<Double, Double>();
		Map<Double, String> PLeftperMonthMap = new HashMap<Double, String>();
		Map<Double, String> PRperMonthMap = new HashMap<Double, String>();
		Map<Double, String> PperMonthMap = new HashMap<Double, String>();
		Map<Double, String> RperMonthMap = new HashMap<Double, String>();
		Map<Double, Double> sumPRMap = new HashMap<Double, Double>();
		Map<Double, Double> sumPMap = new HashMap<Double, Double>();
		Map<Double, Double> sumRMap = new HashMap<Double, Double>();

		if (IncreaseFlag == 1) {
			while (perMonthStandard < perMonthMax) {
				PRperMonth[0] = RepayUtils.num2second(perMonthStandard);
				PLeftperMonth[0] = RepayUtils.num2second(invest);
				RperMonth[0] = RepayUtils.num2secondDown(PLeftperMonth[0] * daysCount[0] * dateRate);
				PperMonth[0] = RepayUtils.num2second(PRperMonth[0] - RperMonth[0]);
				for (int j = 1; j < totalmonth; j++) {
					PRperMonth[j] = RepayUtils.num2second(perMonthStandard);
					PLeftperMonth[j] = RepayUtils.num2second(PLeftperMonth[j - 1] - PperMonth[j - 1]);
					RperMonth[j] = RepayUtils.num2secondDown(PLeftperMonth[j] * dateRate * daysCount[j]);
					PperMonth[j] = RepayUtils.num2second(PRperMonth[j] - RperMonth[j]);
					if (j == totalmonth - 1) {
						PperMonth[j] = RepayUtils.num2second(PLeftperMonth[j]);
						PRperMonth[j] = RepayUtils.num2second(PperMonth[j] + RperMonth[j]);
					}
				}
				double sumP = 0;
				double sumR = 0;
				double sumPR = 0;
				for (int i = 0; i < PLeftperMonth.length; i++) {
					sumP = sumP + PperMonth[i];
					sumR = sumR + RperMonth[i];
					sumPR = sumPR + PRperMonth[i];
				}
				lastCheckMap.put(RepayUtils.num2second(perMonthStandard),
						Math.abs(PRperMonth[totalmonth - 1] - PRperMonth[totalmonth - 2]));
				PLeftperMonthMap.put(RepayUtils.num2second(perMonthStandard), Arrays.toString(PLeftperMonth));
				PRperMonthMap.put(RepayUtils.num2second(perMonthStandard), Arrays.toString(PRperMonth));
				PperMonthMap.put(RepayUtils.num2second(perMonthStandard), Arrays.toString(PperMonth));
				RperMonthMap.put(RepayUtils.num2second(perMonthStandard), Arrays.toString(RperMonth));
				sumPRMap.put(RepayUtils.num2second(perMonthStandard), RepayUtils.num2second(sumPR));
				sumPMap.put(RepayUtils.num2second(perMonthStandard), RepayUtils.num2second(sumP));
				sumRMap.put(RepayUtils.num2second(perMonthStandard), RepayUtils.num2second(sumR));

				perMonthStandard = perMonthStandard + 0.01;
			}
		}

		Double resultKey = RepayUtils.getKeyByMinValue(lastCheckMap);

		System.out.println("等额本息每月还款额：" + resultKey);
		System.out.println("每期经历" + Arrays.toString(daysCount));
		System.out.println("每月余本金:" + PLeftperMonthMap.get(resultKey));
		System.out.println("每月还款额:" + PRperMonthMap.get(resultKey));
		System.out.println("每月还本金:" + PperMonthMap.get(resultKey));
		System.out.println("每月还利息:" + RperMonthMap.get(resultKey));
		System.out.println("总还款额:" + sumPRMap.get(resultKey));
		System.out.println("总还本金:" + sumPMap.get(resultKey));
		System.out.println("总还利息:" + sumRMap.get(resultKey));
		return resultKey;
	}

}