java中每月等额与先息后本计算
一般信用贷款会提供两种还款方式:每月等额或者先息后本。每月等额,就是每月归还等同的部分本金和利息,你手里在使用的本金其实是逐月减少的。先息后本就是先还利息,到期归还本金。
每月等额
import java.math.BigDecimal; import java.util.Calendar; import java.util.Date; /** * <p>Title: 等额本息还款工具类</p> * */ public class CPMUtils{ /** * <p>Description: 每月还款总额。〔贷款本金×月利率×(1+月利率)^还款月数〕÷〔(1+月利率)^还款月数-1〕</p> * @param principal 贷款本金 * @param monthlyInterestRate 月利率 * @param amount 期数 * @return */ public static BigDecimal monthlyRepayment(BigDecimal principal, BigDecimal monthlyInterestRate, int amount){ //(1+月利率)^还款月数 BigDecimal temp = monthlyInterestRate.add(MoneyUtils.ONE).pow(amount); return principal.multiply(monthlyInterestRate) .multiply(temp) .divide(temp.subtract(MoneyUtils.ONE), MoneyUtils.MATHCONTEXT); } /** * <p>Description: 月还款利息。(贷款本金×月利率-月还款额)*(1+月利率)^(当前期数-1)+月还款额</p> * @param principal 贷款本金 * @param monthlyInterestRate 月利率 * @param monthlyRepayment 月还款额 * @param number 当前期数 * @return */ public static BigDecimal monthlyInterest(BigDecimal principal, BigDecimal monthlyInterestRate, BigDecimal monthlyRepayment, int number){ //(1+月利率)^(当前期数-1) BigDecimal temp = monthlyInterestRate.add(MoneyUtils.ONE).pow(number - 1); return principal.multiply(monthlyInterestRate) .subtract(monthlyRepayment) .multiply(temp).add(monthlyRepayment, MoneyUtils.MATHCONTEXT); } /** * <p>Description: 还款总利息。期数×贷款本金×月利率×(1+月利率)^期数÷〔(1+月利率)^期数-1〕-贷款本金 </p> * @param principal 贷款本金 * @param monthlyInterestRate 月利率 * @param amount 还款期数 * @return */ public static BigDecimal interest(BigDecimal principal, BigDecimal monthlyInterestRate, int amount){ //(1+月利率)^期数 BigDecimal temp = monthlyInterestRate.add(MoneyUtils.ONE).pow(amount); return new BigDecimal(amount) .multiply(principal) .multiply(monthlyInterestRate) .multiply(temp) .divide(temp.subtract(MoneyUtils.ONE), MoneyUtils.MATHCONTEXT) .subtract(principal, MoneyUtils.MATHCONTEXT); } /** * <p>Description: 月还款本金。已经精确到分位,未做单位换算</p> * @param principal 贷款本金 * @param monthlyInterestRate 月利率 * @param monthlyRepayment 月还款额 * @param number 当前期数 * @return */ public static BigDecimal monthlyPrincipal(BigDecimal principal, BigDecimal monthlyInterestRate, BigDecimal monthlyRepayment, int number){ BigDecimal monthInterest = monthlyInterest(principal, monthlyInterestRate, monthlyRepayment, number); //月还款额-月还款利息 return monthlyRepayment.subtract(monthInterest).setScale(MoneyUtils.MONEYSHOWSCALE, MoneyUtils.SAVEROUNDINGMODE); } /** * <p>Description: 月还款本金。已经精确到分位,未做单位换算</p> * @param monthRepayment 月还款总额 * @param monthInterest 月还款利息 * @return */ public static BigDecimal monthPrincipal(BigDecimal monthRepayment, BigDecimal monthInterest){ //月还款总额-月还款利息 return monthRepayment.subtract(monthInterest).setScale(MoneyUtils.MONEYSHOWSCALE, MoneyUtils.SAVEROUNDINGMODE); } }
先息后本
import java.math.BigDecimal; /** * <p>Title: 先息后本还款方式工具类型</p> */ public class BIAPPUtils extends RepaymentUtils { /** * <p>Description: 月还款利息 贷款本金×月利率 </p> * @param loan 贷款本金 * @param monthlyInterestRate 月利率 * @return */ public static BigDecimal monthlyInterest(BigDecimal loan, BigDecimal monthlyInterestRate){ return loan.multiply(monthlyInterestRate, MoneyUtils.MATHCONTEXT); } /** * <p>Description: 还款总利息 贷款本金×月利率×期数</p> * @param loan 贷款本金 * @param monthlyInterestRate 月利率 * @param number 期数 * @return */ public static BigDecimal interest(BigDecimal loan, BigDecimal monthlyInterestRate, int number){ return loan.multiply(monthlyInterestRate).multiply(new BigDecimal(number), MoneyUtils.MATHCONTEXT); } /** * <p>Description: 月还款额</p> * @param loan 贷款本金 * @param monthlyInterestRate 月利率 * @param amount 期数 * @param curNumber 当前期数 * @return */ public static BigDecimal monthlyRepayment(BigDecimal loan, BigDecimal monthlyInterestRate, int amount, int curNumber){ BigDecimal monthlyInterest = monthlyInterest(loan, monthlyInterestRate); if(amount == curNumber){ return monthlyInterest.add(loan, MoneyUtils.MATHCONTEXT);//最后月还款额 }else{ return monthlyInterest; } } }
*金额计算工具类
import java.math.BigDecimal; import java.math.MathContext; import java.math.RoundingMode; import java.text.NumberFormat; public class MoneyUtils { /** * 标度(小数位数) */ public static final int SCALE = 10; /** * 金钱显示标度(小数位数) */ public static final int MONEYSHOWSCALE = 2; /** * 利率显示标度(小数位数) */ public static final int INTERESTRATESHOWSCALE = 4; /** * 精度 */ public static final int PRECISION = 30; /** * 保存舍入规则 */ public static final RoundingMode SAVEROUNDINGMODE = RoundingMode.HALF_UP; /** * 是否舍去小数点最后的零 */ public static boolean STRIPTRAILINGZEROS = true; /** * 运算上下文(设置精度、舍入规则) */ public static final MathContext MATHCONTEXT = new MathContext(PRECISION, SAVEROUNDINGMODE); /** * 每年天数 */ public static final String YEARDAYS = "360"; /** * 每年月数 */ public static final String YEARMOTHS = "12"; /** * 每月天数 */ public static final String MOTHDAYS = "30"; /** * 数字“1” */ public static final BigDecimal ONE = new BigDecimal(1); /** * 数字“100” */ public static final BigDecimal HUNDRED = new BigDecimal(100); /** * 数字“0.01” */ public static final BigDecimal ONEHUNDREDTH = new BigDecimal(0.01); public static BigDecimal newBigDecimal(String str){ return (str == null || str.trim().isEmpty()) ? BigDecimal.ZERO : new BigDecimal(str); } /** * <p>Description: 加法返回格式化结果数字</p> * @param addend * @param augend * @return */ public static BigDecimal add(BigDecimal addend, BigDecimal augend){ return formatMoney(addend.add(augend, MATHCONTEXT)); } /** * <p>Description: 加法返回格式化结果数字</p> * @param addend * @param augend * @return */ public static BigDecimal add(String addend, String augend){ BigDecimal decimalAddend = newBigDecimal(addend); BigDecimal decimalAugend = newBigDecimal(augend); return formatMoney(decimalAddend.add(decimalAugend, MATHCONTEXT)); } /** * <p>Description: 加法返回格式化结果字符串</p> * @param addend * @param augend * @return */ public static String addToString(BigDecimal addend, BigDecimal augend){ return formatToString(addend.add(augend, MATHCONTEXT)); } /** * <p>Description: 加法返回格式化结果字符串</p> * @param addend * @param augend * @return */ public static String addToString(String addend, String augend){ BigDecimal decimalAddend = newBigDecimal(addend); BigDecimal decimalAugend = newBigDecimal(augend); return formatToString(decimalAddend.add(decimalAugend, MATHCONTEXT)); } /** * <p>Description: 减法返回格式化结果数字</p> * @param minuend * @param subtrahend * @return */ public static BigDecimal subtract(BigDecimal minuend, BigDecimal subtrahend){ return formatMoney(minuend.subtract(subtrahend, MATHCONTEXT)); } /** * <p>Description: 减法返回格式化结果数字</p> * @param minuend * @param subtrahend * @return */ public static BigDecimal subtract(String minuend, String subtrahend){ BigDecimal decimalMinuend = newBigDecimal(minuend); BigDecimal decimalSubtrahend = newBigDecimal(subtrahend); return formatMoney(decimalMinuend.subtract(decimalSubtrahend, MATHCONTEXT)); } /** * <p>Description: 减法返回格式化结果字符串</p> * @param minuend * @param subtrahend * @return */ public static String subtractToString(BigDecimal minuend, BigDecimal subtrahend){ return formatToString(minuend.subtract(subtrahend, MATHCONTEXT)); } /** * <p>Description: 减法返回格式化结果字符串</p> * @param minuend * @param subtrahend * @return */ public static String subtractToString(String minuend, String subtrahend){ BigDecimal decimalMinuend = newBigDecimal(minuend); BigDecimal decimalSubtrahend = newBigDecimal(subtrahend); return formatToString(decimalMinuend.subtract(decimalSubtrahend, MATHCONTEXT)); } /** * <p>Description: 乘法返回格式化结果数字</p> * @param multiplier * @param multiplicand * @return */ public static BigDecimal multiply(BigDecimal multiplier, BigDecimal multiplicand){ return formatMoney(multiplier.multiply(multiplicand, MATHCONTEXT)); } /** * <p>Description: 乘法返回格式化结果数字</p> * @param multiplier * @param multiplicand * @return */ public static BigDecimal multiply(String multiplier, String multiplicand){ BigDecimal decimalMultiplier = newBigDecimal(multiplier); BigDecimal decimalMultiplicand = newBigDecimal(multiplicand); return formatMoney(decimalMultiplier.multiply(decimalMultiplicand, MATHCONTEXT)); } /** * <p>Description: 乘法返回格式化结果字符串</p> * @param multiplier * @param multiplicand * @return */ public static String multiplyToString(BigDecimal multiplier, BigDecimal multiplicand){ return formatToString(multiplier.multiply(multiplicand, MATHCONTEXT)); } /** * <p>Description: 乘法返回格式化结果字符串</p> * @param multiplier * @param multiplicand * @return */ public static String multiplyToString(String multiplier, String multiplicand){ BigDecimal decimalMultiplier = newBigDecimal(multiplier); BigDecimal decimalMultiplicand = newBigDecimal(multiplicand); return formatToString(decimalMultiplier.multiply(decimalMultiplicand, MATHCONTEXT)); } /** * <p>Description: 除法返回格式化结果数字</p> * @param dividend * @param divisor * @return */ public static BigDecimal divide(BigDecimal dividend, BigDecimal divisor){ return formatMoney(dividend.divide(divisor, MATHCONTEXT)); } /** * <p>Description: 除法返回格式化结果数字</p> * @param dividend * @param divisor * @return */ public static BigDecimal divide(String dividend, String divisor){ BigDecimal decimalDividend = newBigDecimal(dividend); BigDecimal decimalDivisor = newBigDecimal(divisor); return formatMoney(decimalDividend.divide(decimalDivisor, MATHCONTEXT)); } /** * <p>Description: 除法返回格式化结果字符串</p> * @param dividend * @param divisor * @return */ public static String divideToString(BigDecimal dividend, BigDecimal divisor){ return formatToString(dividend.divide(divisor, MATHCONTEXT)); } /** * <p>Description: 除法返回格式化结果字符串</p> * @param dividend * @param divisor * @return */ public static String divideToString(String dividend, String divisor){ BigDecimal decimalDividend = newBigDecimal(dividend); BigDecimal decimalDivisor = newBigDecimal(divisor); return formatToString(decimalDividend.divide(decimalDivisor, MATHCONTEXT)); } /** * <p>Description: 月利率计算</p> * @param yearInterestRate * @return */ public static BigDecimal monthInterestRate(BigDecimal yearInterestRate){ BigDecimal dayInterestRate = MoneyUtils.divide(yearInterestRate, YEARDAYS).setScale(5, RoundingMode.CEILING); System.err.println(dayInterestRate); BigDecimal monthInterestRate = dayInterestRate.multiply(newBigDecimal(MOTHDAYS)); System.err.println(monthInterestRate); return monthInterestRate; } /** * <p>Description: 按既定小数位数格式化金额保存</p> * @param result * @return */ public static BigDecimal formatMoney(BigDecimal result){ return result.setScale(SCALE, SAVEROUNDINGMODE); } /** * <p>Description: 按既定小数位数格式化金额显示</p> * @param resultStr 要格式化的数 * @param multiple 乘以的倍数 * @return */ public static String formatMoneyToShow(String resultStr, BigDecimal multiple){ BigDecimal result = newBigDecimal(resultStr); return MoneyUtils.formatToString(MoneyUtils.formatMoneyToShow(result, multiple)); } /** * <p>Description: 按既定小数位数格式化金额显示</p> * @param result 要格式化的数 * @param multiple 乘以的倍数 * @return */ public static BigDecimal formatMoneyToShow(BigDecimal result, BigDecimal multiple){ return result.multiply(multiple).setScale(MONEYSHOWSCALE, SAVEROUNDINGMODE); } /** * <p>Description: 按既定小数位数格式化利率显示</p> * @param result 要格式化的数 * @param multiple 乘以的倍数 * @return */ public static BigDecimal formatInterestRateToShow(BigDecimal result, BigDecimal multiple){ return result.multiply(multiple).setScale(INTERESTRATESHOWSCALE, SAVEROUNDINGMODE); } /** * <p>Description: 按既定小数位数格式化显示</p> * @param result 要格式化的数 * @param scale 显示标度(小数位数) * @return */ public static BigDecimal formatToShow(BigDecimal result, int scale){ return result.setScale(scale, SAVEROUNDINGMODE); } /** * <p>Description: 格式化为字符串,进行去零不去零操作</p> * @param result * @return */ public static String formatToString(BigDecimal result){ if(result == null){ return ""; }else{ return STRIPTRAILINGZEROS ? result.stripTrailingZeros().toPlainString() : result.toPlainString(); } } /** * <p>Description: 按既定小数位数格式化为货币格式</p> * @param result * @return */ public static String formatToCurrency(BigDecimal result){ BigDecimal temp = result.divide(HUNDRED, SAVEROUNDINGMODE); NumberFormat numberFormat = NumberFormat.getCurrencyInstance(); return numberFormat.format(STRIPTRAILINGZEROS ? temp.stripTrailingZeros() : temp); } public static String formatToPercent(BigDecimal result){ BigDecimal temp = result.divide(HUNDRED, SAVEROUNDINGMODE); NumberFormat numberFormat = NumberFormat.getPercentInstance(); return numberFormat.format(STRIPTRAILINGZEROS ? temp.stripTrailingZeros() : temp); } /** * <p>Description:格式化数字为千分位显示; </p> * @param text * @return */ public static String fmtMicrometer(String text){ DecimalFormat df = null; if(text.indexOf(".") > 0) { if(text.length() - text.indexOf(".")-1 == 0){ df = new DecimalFormat("###,##0."); }else if(text.length() - text.indexOf(".")-1 == 1){ df = new DecimalFormat("###,##0.0"); }else { df = new DecimalFormat("###,##0.00"); } }else{ df = new DecimalFormat("###,##0.00"); } double number = 0.0; try { number = Double.parseDouble(text); } catch (Exception e) { number = 0.0; } return df.format(number); } }
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