/**
* Description:等额本金工具类
*/
import com.google.common.collect.Maps;
import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
/**
* 等额本金是指一种贷款的还款方式，是在还款期内把贷款数总额等分，每月偿还同等数额的本金和剩余贷款在该月所产生的利息，这样由于每月的还款本金额固定，
* 而利息越来越少，借款人起初还款压力较大，但是随时间的推移每月还款数也越来越少。
*/
public class AverageCapitalUtils {
/**
* 等额本金计算获取还款方式为等额本金的每月偿还本金和利息
*
* 公式：每月偿还本金=(贷款本金÷还款月数)+(贷款本金-已归还本金累计额)×月利率
*
* @param invest
* 总借款额（贷款本金）
* @param yearRate
* 年利率
* @param month
* 还款总月数
* @return 每月偿还本金和利息,不四舍五入，直接截取小数点最后两位
*/
public static Map<Integer, Double> getPerMonthPrincipalInterest(double invest, double yearRate, int totalMonth) {
Map<Integer, Double> map = new HashMap<Integer, Double>();
// 每月本金
double monthPri = getPerMonthPrincipal(invest, totalMonth);
// 获取月利率
double monthRate = yearRate / 12;
monthRate = new BigDecimal(monthRate).setScale(6, BigDecimal.ROUND_DOWN).doubleValue();
for (int i = 1; i <= totalMonth; i++) {
double monthRes = monthPri + (invest - monthPri * (i - 1)) * monthRate;
monthRes = new BigDecimal(monthRes).setScale(2, BigDecimal.ROUND_DOWN).doubleValue();
map.put(i, monthRes);
}
return map;
}
/**
* 等额本金计算获取还款方式为等额本金的每月偿还利息
*
* 公式：每月应还利息=剩余本金×月利率=(贷款本金-已归还本金累计额)×月利率
*
* @param invest
* 总借款额（贷款本金）
* @param yearRate
* 年利率
* @param month
* 还款总月数
* @return 每月偿还利息
*/
public static Map<Integer, Double> getPerMonthInterest(double invest, double yearRate, int totalMonth) {
Map<Integer, Double> inMap = new HashMap<Integer, Double>();
double principal = getPerMonthPrincipal(invest, totalMonth);
Map<Integer, Double> map = getPerMonthPrincipalInterest(invest, yearRate, totalMonth);
for (Map.Entry<Integer, Double> entry : map.entrySet()) {
BigDecimal principalBigDecimal = new BigDecimal(principal);
BigDecimal principalInterestBigDecimal = new BigDecimal(entry.getValue());
BigDecimal interestBigDecimal = principalInterestBigDecimal.subtract(principalBigDecimal);
interestBigDecimal = interestBigDecimal.setScale(2, BigDecimal.ROUND_DOWN);
inMap.put(entry.getKey(), interestBigDecimal.doubleValue());
}
return inMap;
}
/**
* 等额本金计算获取还款方式为等额本金的每月偿还本金
*
* 公式：每月应还本金=贷款本金÷还款月数
*
* @param invest
* 总借款额（贷款本金）
* @param yearRate
* 年利率
* @param month
* 还款总月数
* @return 每月偿还本金
*/
public static double getPerMonthPrincipal(double invest, int totalMonth) {
BigDecimal monthIncome = new BigDecimal(invest).divide(new BigDecimal(totalMonth), 2, BigDecimal.ROUND_DOWN);
return monthIncome.doubleValue();
}
/**
* 等额本金计算获取还款方式为等额本金的总利息
*
* @param invest
* 总借款额（贷款本金）
* @param yearRate
* 年利率
* @param month
* 还款总月数
* @return 总利息
*/
public static double getInterestCount(double invest, double yearRate, int totalMonth) {
BigDecimal count = new BigDecimal(0);
Map<Integer, Double> mapInterest = getPerMonthInterest(invest, yearRate, totalMonth);
for (Map.Entry<Integer, Double> entry : mapInterest.entrySet()) {
count = count.add(new BigDecimal(entry.getValue()));
}
return count.doubleValue();
}
/**
* @param args
*/
public static void main(String[] args) {
double invest = 800000; // 本金
int month = 120;
double yearRate = 0.052; // 年利率
Map<Integer, Double> getPerMonthPrincipalInterest = getPerMonthPrincipalInterest(invest, yearRate, month);
System.out.println("等额本金---每月本息：" + getPerMonthPrincipalInterest);
double benjin = getPerMonthPrincipal(invest, month);
System.out.println("等额本金---每月本金:" + benjin);
Map<Integer, Double> mapInterest = getPerMonthInterest(invest, yearRate, month);
System.out.println("等额本金---每月利息:" + mapInterest);
Map<Integer, Double> mapInterestCount = Maps.newHashMap();
for(Map.Entry<Integer, Double> entry : mapInterest.entrySet()){
int curMonth = entry.getKey();
Double curIntersetCount = 0d;
if(curMonth > 1){
curIntersetCount = entry.getValue() + mapInterestCount.get(curMonth - 1);
}else {
curIntersetCount = entry.getValue();
}
Double value = new BigDecimal(String.valueOf(curIntersetCount)).setScale(2, BigDecimal.ROUND_DOWN).doubleValue();
mapInterestCount.put(curMonth, value);
}
System.out.println("等额本金---各月加和:" + mapInterestCount);
double count = getInterestCount(invest, yearRate, month);
System.out.println("等额本金---总利息：" + count);
}
}
import com.google.common.collect.Maps;
import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Map;
public class AverageCapitalPlusInterestUtils {
/**
* 等额本息计算获取还款方式为等额本息的每月偿还本金和利息
* <p>
* 公式：每月偿还本息=〔贷款本金×月利率×(1＋月利率)＾还款月数〕÷〔(1＋月利率)＾还款月数-1〕
*
* @param invest 总借款额（贷款本金）
* @param yearRate 年利率
* @param month 还款总月数
* @return 每月偿还本金和利息, 不四舍五入，直接截取小数点最后两位
*/
public static double getPerMonthPrincipalInterest(double invest, double yearRate, int totalmonth) {
double monthRate = yearRate / 12;
BigDecimal monthIncome = new BigDecimal(invest)
.multiply(new BigDecimal(monthRate * Math.pow(1 + monthRate, totalmonth)))
.divide(new BigDecimal(Math.pow(1 + monthRate, totalmonth) - 1), 2, BigDecimal.ROUND_DOWN);
return monthIncome.doubleValue();
}
/**
* 等额本息计算获取还款方式为等额本息的每月偿还利息
* <p>
* 公式：每月偿还利息=贷款本金×月利率×〔(1+月利率)^还款月数-(1+月利率)^(还款月序号-1)〕÷〔(1+月利率)^还款月数-1〕
*
* @param invest 总借款额（贷款本金）
* @param yearRate 年利率
* @param month 还款总月数
* @return 每月偿还利息
*/
public static Map<Integer, BigDecimal> getPerMonthInterest(double invest, double yearRate, int totalmonth) {
Map<Integer, BigDecimal> map = new HashMap<Integer, BigDecimal>();
double monthRate = yearRate / 12;
BigDecimal monthInterest;
for (int i = 1; i < totalmonth + 1; i++) {
BigDecimal multiply = new BigDecimal(invest).multiply(new BigDecimal(monthRate));
BigDecimal sub = new BigDecimal(Math.pow(1 + monthRate, totalmonth)).subtract(new BigDecimal(Math.pow(1 + monthRate, i - 1)));
monthInterest = multiply.multiply(sub).divide(new BigDecimal(Math.pow(1 + monthRate, totalmonth) - 1), 6, BigDecimal.ROUND_DOWN);
monthInterest = monthInterest.setScale(2, BigDecimal.ROUND_DOWN);
map.put(i, monthInterest);
}
return map;
}
/**
* 等额本息计算获取还款方式为等额本息的每月偿还本金
*
* @param invest 总借款额（贷款本金）
* @param yearRate 年利率
* @param month 还款总月数
* @return 每月偿还本金
*/
public static Map<Integer, BigDecimal> getPerMonthPrincipal(double invest, double yearRate, int totalmonth) {
double monthRate = yearRate / 12;
BigDecimal monthIncome = new BigDecimal(invest)
.multiply(new BigDecimal(monthRate * Math.pow(1 + monthRate, totalmonth)))
.divide(new BigDecimal(Math.pow(1 + monthRate, totalmonth) - 1), 2, BigDecimal.ROUND_DOWN);
Map<Integer, BigDecimal> mapInterest = getPerMonthInterest(invest, yearRate, totalmonth);
Map<Integer, BigDecimal> mapPrincipal = new HashMap<Integer, BigDecimal>();
for (Map.Entry<Integer, BigDecimal> entry : mapInterest.entrySet()) {
mapPrincipal.put(entry.getKey(), monthIncome.subtract(entry.getValue()));
}
return mapPrincipal;
}
/**
* 等额本息计算获取还款方式为等额本息的总利息
*
* @param invest 总借款额（贷款本金）
* @param yearRate 年利率
* @param month 还款总月数
* @return 总利息
*/
public static double getInterestCount(double invest, double yearRate, int totalmonth) {
BigDecimal count = new BigDecimal(0);
Map<Integer, BigDecimal> mapInterest = getPerMonthInterest(invest, yearRate, totalmonth);
for (Map.Entry<Integer, BigDecimal> entry : mapInterest.entrySet()) {
count = count.add(entry.getValue());
}
return count.doubleValue();
}
/**
* 应还本金总和
*
* @param invest 总借款额（贷款本金）
* @param yearRate 年利率
* @param month 还款总月数
* @return 应还本金总和
*/
public static double getPrincipalInterestCount(double invest, double yearRate, int totalmonth) {
double monthRate = yearRate / 12;
BigDecimal perMonthInterest = new BigDecimal(invest)
.multiply(new BigDecimal(monthRate * Math.pow(1 + monthRate, totalmonth)))
.divide(new BigDecimal(Math.pow(1 + monthRate, totalmonth) - 1), 2, BigDecimal.ROUND_DOWN);
BigDecimal count = perMonthInterest.multiply(new BigDecimal(totalmonth));
count = count.setScale(2, BigDecimal.ROUND_DOWN);
return count.doubleValue();
}
/**
* @param args
*/
public static void main(String[] args) {
double invest = 800000; // 本金
int month = 120;
double yearRate = 0.052; // 年利率
double perMonthPrincipalInterest = getPerMonthPrincipalInterest(invest, yearRate, month);
System.out.println("等额本息---每月还款本息：" + perMonthPrincipalInterest);
Map<Integer, BigDecimal> mapInterest = getPerMonthInterest(invest, yearRate, month);
System.out.println("等额本息---每月还款利息：" + mapInterest);
Map<Integer, BigDecimal> mapInterestCount = Maps.newHashMap();
for(Map.Entry<Integer, BigDecimal> entry : mapInterest.entrySet()){
int curMonth = entry.getKey();
BigDecimal curIntersetCount = new BigDecimal(0);
if(curMonth > 1){
curIntersetCount = entry.getValue().add(mapInterestCount.get(curMonth - 1));
}else {
curIntersetCount = entry.getValue();
}
mapInterestCount.put(curMonth, curIntersetCount);
}
System.out.println("等额本金---各月加和:" + mapInterestCount);
Map<Integer, BigDecimal> mapPrincipal = getPerMonthPrincipal(invest, yearRate, month);
System.out.println("等额本息---每月还款本金：" + mapPrincipal);
double count = getInterestCount(invest, yearRate, month);
System.out.println("等额本息---总利息：" + count);
double principalInterestCount = getPrincipalInterestCount(invest, yearRate, month);
System.out.println("等额本息---应还本息总和：" + principalInterestCount);
}
}
import com.google.common.collect.Maps;
import java.math.BigDecimal;
import java.util.Map;
/**
* 提前还贷款：http://www.zuhedaikuan.com/jsq/tiqian.aspx
*/
public class House {
public static void main(String[] args) {
testHose(580000, 0.052, 60);
System.out.println();
System.out.println();
System.out.println();
testHose(500000, 0.0325, 120);
}
public static void testHose(double invest, double yearRate, int month){
Map<Integer, Double> getPerMonthPrincipalInterest = AverageCapitalUtils.getPerMonthPrincipalInterest(invest, yearRate, month);
System.out.println("等额本金---每月本息：" + getPerMonthPrincipalInterest);
double perMonthPrincipalInterestPlus = AverageCapitalPlusInterestUtils.getPerMonthPrincipalInterest(invest, yearRate, month);
System.out.println("等额本息---每月本息：" + perMonthPrincipalInterestPlus);
System.out.println();
double benjin = AverageCapitalUtils.getPerMonthPrincipal(invest, month);
System.out.println("等额本金---每月本金：" + benjin);
Map<Integer, BigDecimal> mapPrincipalPlus = AverageCapitalPlusInterestUtils.getPerMonthPrincipal(invest, yearRate, month);
System.out.println("等额本息---每月本金：" + mapPrincipalPlus);
System.out.println();
double benjinMonth = AverageCapitalUtils.getPerMonthPrincipal(invest, month);
Map<Integer, BigDecimal> benjinAll = Maps.newHashMap();
for(int i=0; i<month ;i++){
if(i == 0){
benjinAll.put(i + 1, new BigDecimal(String.valueOf(benjinMonth)));
}else {
benjinAll.put(i + 1, benjinAll.get(i).add(new BigDecimal(String.valueOf(benjinMonth))));
}
}
System.out.println("等额本金---已还本金：" + benjinAll);
Map<Integer, BigDecimal> mapPrincipalAll = Maps.newHashMap();
for(Map.Entry<Integer, BigDecimal> entry : AverageCapitalPlusInterestUtils.getPerMonthPrincipal(invest, yearRate, month).entrySet()) {
int curMonth = entry.getKey();
BigDecimal curIntersetCount = new BigDecimal(0);
if(curMonth > 1){
curIntersetCount = entry.getValue().add(mapPrincipalAll.get(curMonth - 1));
}else {
curIntersetCount = entry.getValue();
}
mapPrincipalAll.put(curMonth, curIntersetCount);
}
System.out.println("等额本息---已还本金：" + mapPrincipalAll);
System.out.println();
Map<Integer, Double> mapInterest = AverageCapitalUtils.getPerMonthInterest(invest, yearRate, month);
System.out.println("等额本金---每月利息：" + mapInterest);
Map<Integer, BigDecimal> mapInterestPlus = AverageCapitalPlusInterestUtils.getPerMonthInterest(invest, yearRate, month);
System.out.println("等额本息---每月利息：" + mapInterestPlus);
System.out.println();
Map<Integer, Double> mapInterestCount = Maps.newHashMap();
for(Map.Entry<Integer, Double> entry : mapInterest.entrySet()){
int curMonth = entry.getKey();
Double curIntersetCount = 0d;
if(curMonth > 1){
curIntersetCount = entry.getValue() + mapInterestCount.get(curMonth - 1);
}else {
curIntersetCount = entry.getValue();
}
Double value = new BigDecimal(String.valueOf(curIntersetCount)).setScale(2, BigDecimal.ROUND_DOWN).doubleValue();
mapInterestCount.put(curMonth, value);
}
System.out.println("等额本金---各月加和：" + mapInterestCount);
Map<Integer, BigDecimal> mapInterestCountPlus = Maps.newHashMap();
for(Map.Entry<Integer, BigDecimal> entry : mapInterestPlus.entrySet()){
int curMonth = entry.getKey();
BigDecimal curIntersetCountPlus = new BigDecimal(0);
if(curMonth > 1){
curIntersetCountPlus = entry.getValue().add(mapInterestCountPlus.get(curMonth - 1));
}else {
curIntersetCountPlus = entry.getValue();
}
mapInterestCountPlus.put(curMonth, curIntersetCountPlus);
}
System.out.println("等额本金---各月加和：" + mapInterestCountPlus);
System.out.println();
double beforecount = AverageCapitalUtils.getInterestCount(invest, yearRate, month);
System.out.println("等额本金---总利息：" + beforecount);
double beforecountPlus = AverageCapitalPlusInterestUtils.getInterestCount(invest, yearRate, month);
System.out.println("等额本息---总利息：" + beforecountPlus);
}
}