1. /** 
2.  * 阿里借呗计息还款规则说明实现 
3.  *  
4.  * @return 
5.  */  
6. package jdongtech.jiebaiUtils;  
7.   
8. import java.util.Arrays;  
9. import java.util.Calendar;  
10. import java.util.HashMap;  
11. import java.util.Map;  
12.   
13. import jdongtech.interestUtils.AverageCapitalPlusInterestUtils;  
14.   
15. public class normalRepay {  
16.     public static void main(String[] args) {  
17.         // 需要手动填写  
18.         double invest = 120; // 本金  
19.         int month = 6;     // 期数  
20.         double yearRate = 14.4 / 100; // 年利率  
21.         int acctOffsetDay = 15;  
22.         int accountDay = 13;     // 账单日，蚂蚁会把账单日设置成借款当日  
23.         // 发起借款当天  
24.         Calendar lendDay = Calendar.getInstance();  
25.         lendDay.set(Calendar.MONTH, 4);  
26.         lendDay.set(Calendar.DAY_OF_MONTH, 13);  
27.   
28.         double dateRate = yearRate / 360;  
29.         int[] daysCount = new int[month];  
30.         int IncreaseFlag = 0;  
31.         Calendar lendCalOffset = (Calendar) lendDay.clone();  
32.         lendCalOffset.add(Calendar.DATE, acctOffsetDay);  
33.         Calendar accCal = (Calendar) lendDay.clone();  
34.         accCal.set(Calendar.DAY_OF_MONTH, accountDay);  
35.         Calendar accCalBegin = (Calendar) accCal.clone();  
36.         if (lendCalOffset.before(accCal)) {  
37.         } else {  
38.             accCalBegin.add(Calendar.MONTH, 1);  
39.             IncreaseFlag = 1;  
40.         }  
41.         Calendar accCalEnd = (Calendar) accCal.clone();  
42.         accCalEnd.add(Calendar.MONTH, month-1);  
43.   
44.         System.out.println(lendDay.getTime() + "借款日期");  
45.         System.out.println(accCalBegin.getTime() + "开始");  
46.         System.out.println(accCalEnd.getTime() + "结束");  
47.         int daysLending = RepayUtils.daysOffset(lendDay, accCalEnd);  
48.         System.out.println("借款经历" + daysLending + "天");  
49.   
50.         Calendar accCalPerEnd = (Calendar) accCalBegin.clone();  
51.         for (int i = 0; i < month; i++) {  
52.             Calendar accCalPerBeg;  
53.             if (i == 0) {  
54.                 accCalPerBeg = (Calendar) lendDay.clone();  
55.             } else {  
56.                 accCalPerBeg = (Calendar) accCalPerEnd.clone();  
57.                 accCalPerBeg.add(Calendar.MONTH, -1);  
58.             }  
59.   
60.             int daysPer = RepayUtils.daysOffset(accCalPerBeg, accCalPerEnd);  
61.             daysCount[i] = daysPer;  
62.             accCalPerEnd.add(Calendar.MONTH, 1);  
63.         }  
64.         //dateRate=0.0003;  
65.         getPerMonthPrincipalInterestBig(invest, dateRate, month, daysCount, IncreaseFlag);  
66.     }  
67.   
68.     /** 
69.      * 计算实际等额本息每月额度 
70.      *  
71.      * @return 
72.      */  
73.     public static double getPerMonthPrincipalInterestBig(double invest, double dateRate, int totalmonth, int[] daysCount,  
74.             int IncreaseFlag) {  
75.         IncreaseFlag = 1;  
76.         double perMonthStandard = AverageCapitalPlusInterestUtils.getPerMonthPrincipalInterest(invest, dateRate * 360,  
77.                 totalmonth);  
78.           
79.         double perMonthMax = perMonthStandard * 1.1;  
80.         double[] PRperMonth = new double[totalmonth];  
81.         double[] PperMonth = new double[totalmonth];  
82.         double[] RperMonth = new double[totalmonth];  
83.         double[] PLeftperMonth = new double[totalmonth];  
84.         Map<Double, Double> lastCheckMap = new HashMap<Double, Double>();  
85.         Map<Double, String> PLeftperMonthMap = new HashMap<Double, String>();  
86.         Map<Double, String> PRperMonthMap = new HashMap<Double, String>();  
87.         Map<Double, String> PperMonthMap = new HashMap<Double, String>();  
88.         Map<Double, String> RperMonthMap = new HashMap<Double, String>();  
89.         Map<Double, Double> sumPRMap = new HashMap<Double, Double>();  
90.         Map<Double, Double> sumPMap = new HashMap<Double, Double>();  
91.         Map<Double, Double> sumRMap = new HashMap<Double, Double>();  
92.   
93.         if (IncreaseFlag == 1) {  
94.             while (perMonthStandard < perMonthMax) {  
95.                 PRperMonth[0] = RepayUtils.num2second(perMonthStandard);  
96.                 PLeftperMonth[0] = RepayUtils.num2second(invest);  
97.                 RperMonth[0] = RepayUtils.num2secondDown(PLeftperMonth[0] * daysCount[0] * dateRate);  
98.                 PperMonth[0] = RepayUtils.num2second(PRperMonth[0] - RperMonth[0]);  
99.                 for (int j = 1; j < totalmonth; j++) {  
100.                     PRperMonth[j] = RepayUtils.num2second(perMonthStandard);  
101.                     PLeftperMonth[j] = RepayUtils.num2second(PLeftperMonth[j - 1] - PperMonth[j - 1]);  
102.                     RperMonth[j] = RepayUtils.num2secondDown(PLeftperMonth[j] * dateRate * daysCount[j]);  
103.                     PperMonth[j] = RepayUtils.num2second(PRperMonth[j] - RperMonth[j]);  
104.                     if (j == totalmonth - 1) {  
105.                         PperMonth[j] = RepayUtils.num2second(PLeftperMonth[j]);  
106.                         PRperMonth[j] = RepayUtils.num2second(PperMonth[j] + RperMonth[j]);  
107.                     }  
108.                 }  
109.                 double sumP = 0;  
110.                 double sumR = 0;  
111.                 double sumPR = 0;  
112.                 for (int i = 0; i < PLeftperMonth.length; i++) {  
113.                     sumP = sumP + PperMonth[i];  
114.                     sumR = sumR + RperMonth[i];  
115.                     sumPR = sumPR + PRperMonth[i];  
116.                 }  
117.                 lastCheckMap.put(RepayUtils.num2second(perMonthStandard),  
118.                         Math.abs(PRperMonth[totalmonth - 1] - PRperMonth[totalmonth - 2]));  
119.                 PLeftperMonthMap.put(RepayUtils.num2second(perMonthStandard), Arrays.toString(PLeftperMonth));  
120.                 PRperMonthMap.put(RepayUtils.num2second(perMonthStandard), Arrays.toString(PRperMonth));  
121.                 PperMonthMap.put(RepayUtils.num2second(perMonthStandard), Arrays.toString(PperMonth));  
122.                 RperMonthMap.put(RepayUtils.num2second(perMonthStandard), Arrays.toString(RperMonth));  
123.                 sumPRMap.put(RepayUtils.num2second(perMonthStandard), RepayUtils.num2second(sumPR));  
124.                 sumPMap.put(RepayUtils.num2second(perMonthStandard), RepayUtils.num2second(sumP));  
125.                 sumRMap.put(RepayUtils.num2second(perMonthStandard), RepayUtils.num2second(sumR));  
126.   
127.                 perMonthStandard = perMonthStandard + 0.01;  
128.             }  
129.         }  
130.   
131.         Double resultKey = RepayUtils.getKeyByMinValue(lastCheckMap);  
132.   
133.         System.out.println("等额本息每月还款额：" + resultKey);  
134.         System.out.println("每期经历" + Arrays.toString(daysCount));  
135.         System.out.println("每月余本金:" + PLeftperMonthMap.get(resultKey));  
136.         System.out.println("每月还款额:" + PRperMonthMap.get(resultKey));  
137.         System.out.println("每月还本金:" + PperMonthMap.get(resultKey));  
138.         System.out.println("每月还利息:" + RperMonthMap.get(resultKey));  
139.         System.out.println("总还款额:" + sumPRMap.get(resultKey));  
140.         System.out.println("总还本金:" + sumPMap.get(resultKey));  
141.         System.out.println("总还利息:" + sumRMap.get(resultKey));  
142.         return resultKey;  
143.     }  
144.   
145. }  

借呗分期还款模拟