BigDecimal工具类和Java数字处理

package org.lee.study.utils;

import java.math.BigDecimal;


public class ArithmeticUtils {
    private static final int DEF_DIV_SCALE = 10;

    
    public static double add(double v1, double v2){
        BigDecimal b1 = new BigDecimal(String.valueOf(v1));
        BigDecimal b2 = new BigDecimal(String.valueOf(v2));
        return b1.add(b2).doubleValue();
    }

    
    public static BigDecimal add(String v1, String v2){
        BigDecimal b1 = new BigDecimal(v1);
        BigDecimal b2 = new BigDecimal(v2);
        return b1.add(b2);
    }

    
    public static String add(String v1, String v2, int scale){
        if(scale < 0){
            throw new IllegalArgumentException("The scale must be a positive integer or zero");
        }
        BigDecimal b1 = new BigDecimal(v1);
        BigDecimal b2 = new BigDecimal(v2);
        return b1.add(b2).setScale(scale,BigDecimal.ROUND_HALF_UP).toString();
    }

    
    public static double subtraction(double v1, double v2){
        BigDecimal b1 = new BigDecimal(String.valueOf(v1));
        BigDecimal b2 = new BigDecimal(String.valueOf(v2));
        return b1.subtract(b2).doubleValue();
    }

    
    public static BigDecimal subtraction(String v1, String v2){
        BigDecimal b1 = new BigDecimal(v1);
        BigDecimal b2 = new BigDecimal(v2);
        return b1.subtract(b2);
    }

    
    public static String subtraction(String v1, String v2, int scale){
        if(scale < 0){
            throw new IllegalArgumentException("The scale must be a positive integer or zero");
        }
        BigDecimal b1 = new BigDecimal(v1);
        BigDecimal b2 = new BigDecimal(v2);
        return b1.subtract(b2).setScale(scale,BigDecimal.ROUND_HALF_UP).toString();
    }

    
    public static double multiplication(double v1, double v2){
        BigDecimal b1 = new BigDecimal(String.valueOf(v1));
        BigDecimal b2 = new BigDecimal(String.valueOf(v2));
        return b1.multiply(b2).doubleValue();
    }

    
    public static BigDecimal multiplication(String v1, String v2){
        BigDecimal b1 = new BigDecimal(v1);
        BigDecimal b2 = new BigDecimal(v2);
        return b1.multiply(b2);
    }

    
    public static String multiplication(String v1, String v2, int scale){
        if(scale < 0){
            throw new IllegalArgumentException("The scale must be a positive integer or zero");
        }
        BigDecimal b1 = new BigDecimal(v1);
        BigDecimal b2 = new BigDecimal(v2);
        return b1.multiply(b2).setScale(scale,BigDecimal.ROUND_HALF_UP).toString();
    }

    
    private static double division(double v1, double v2){
        return division(v1,v2,DEF_DIV_SCALE);
    }

    
    public static double division(double v1, double v2, int scale){
        if(scale < 0){
            throw new IllegalArgumentException("The scale must be a positive integer or zero");
        }
        BigDecimal b1 = new BigDecimal(String.valueOf(v1));
        BigDecimal b2 = new BigDecimal(String.valueOf(v2));
        return b1.divide(b2, scale, BigDecimal.ROUND_HALF_UP).doubleValue();
    }

    
    public static double round(double v, int scale){
        if(scale < 0){
            throw new IllegalArgumentException("The scale must be a positive integer or zero");
        }
        BigDecimal b = new BigDecimal(String.valueOf(v));
        return b.setScale(scale,BigDecimal.ROUND_HALF_UP).doubleValue();
    }

    
    public static String round(String v, int scale){
        if(scale < 0){
            throw new IllegalArgumentException("The scale must be a positive integer or zero");
        }
        BigDecimal b = new BigDecimal(v);
        return b.setScale(scale,BigDecimal.ROUND_HALF_UP).toString();
    }

    
    public static String remainder(String v1, String v2, int scale){
        if(scale < 0){
            throw new IllegalArgumentException("The scale must be a positive integer or zero");
        }
        BigDecimal b1 = new BigDecimal(v1);
        BigDecimal b2 = new BigDecimal(v2);
        return b1.remainder(b2).setScale(scale, BigDecimal.ROUND_HALF_UP).toString();
    }

    
    public static String remainder(BigDecimal v1, BigDecimal v2, int scale){
        if(scale < 0){
            throw new IllegalArgumentException("The scale must be a positive integer or zero");
        }
        return v1.remainder(v2).setScale(scale, BigDecimal.ROUND_HALF_UP).toString();
    }

    
    public static boolean compare(String v1, String v2){
        BigDecimal b1 = new BigDecimal(v1);
        BigDecimal b2 = new BigDecimal(v2);
        int bj = b1.compareTo(b2);
        boolean res;
        if(bj>0) {
            res = true;
        }
        else {
            res = false;
        }
        return res;
    }
}

package org.lee.study;

import java.math.BigDecimal;
import java.text.NumberFormat;


public class BigDecimalDemo {
    public static void main(String[] args) {
        NumberFormat currency = NumberFormat.getCurrencyInstance();
        //送参数指定国家币种 Locale.FRANCE,默认是人民币
        NumberFormat percent = NumberFormat.getPercentInstance();
        percent.setMaximumFractionDigits(3);

        BigDecimal loanAmount = new BigDecimal("15000.48");
        BigDecimal interestRate = new BigDecimal("0.008");
        BigDecimal interest = loanAmount.multiply(interestRate);

        System.out.println("贷款金额:t" + currency.format(loanAmount));
        System.out.println("利率:t" + percent.format(interestRate));
        System.out.println("利息:t" + currency.format(interest));
    }
}

package org.lee.study.utils;

import java.text.DecimalFormat;
import java.text.NumberFormat;


public class NumberDealUtils {
    
    public static String trimZero(boolean isFormat, double num) {
        NumberFormat nf = NumberFormat.getInstance();
        if (!isFormat) {
            //设置输出格式是否使用“,”分组,默认是使用的
            nf.setGroupingUsed(false);
        }
        return nf.format(num);
    }

    
    public static String trimZero(boolean isFormat, double num, int fractionDigit) {
        NumberFormat nf = NumberFormat.getInstance();
        nf.setMaximumFractionDigits(fractionDigit);
        if (!isFormat) {
            //设置输出格式是否使用“,”分组,默认是使用的
            nf.setGroupingUsed(false);
        }
        return nf.format(num);
    }

    
    public static String addZeroFormat(double num, int integerDigit, int fractionDigit) {
        StringBuilder rule = new StringBuilder();
        if (integerDigit <= 0) {
            rule.append("#");
        } else {
            for (int i = 0; i < integerDigit; i++) {
                rule.append("0");
            }
        }
        if (fractionDigit > 0) {
            rule.append(".");
            for (int i = 0; i < fractionDigit; i++) {
                rule.append("0");
            }
        }
        DecimalFormat df = new DecimalFormat(rule.toString());
        return df.format(num);
    }

    
    public static String fractionDigitFormat(double num, int fractionDigit) {
        NumberFormat nf = NumberFormat.getInstance();
        nf.setMaximumFractionDigits(fractionDigit);
        //设置输出格式是否使用“,”分组,这里不使用
        nf.setGroupingUsed(false);
        return nf.format(num);
    }
}