java怎么处理大数相加

java怎么处理大数相加

package eshop.framework.util;

import java.math.BigDecimal;

public class AmountUtil {
// 默认除法运算精度
private static final int DEFAULT_DIV_SCALE = 2;


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


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


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


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


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


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


public static double divide(double v1, double v2) {
return divide(v1, v2, DEFAULT_DIV_SCALE);
}


public static double divide(double v1, double v2, int scale) {
return divide(v1, v2, scale, BigDecimal.ROUND_HALF_EVEN);
}


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


public static String divide(String v1, String v2) {
return divide(v1, v2, DEFAULT_DIV_SCALE);
}


public static String divide(String v1, String v2, int scale) {
return divide(v1, v2, DEFAULT_DIV_SCALE, BigDecimal.ROUND_HALF_EVEN);
}


public static String divide(String v1, String v2, int scale, int round_mode) {
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.divide(b2, scale, round_mode).toString();
}


public static double round(double v, int scale) {
return round(v, scale, BigDecimal.ROUND_HALF_EVEN);
}


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


public static String round(String v, int scale) {
return round(v, scale, BigDecimal.ROUND_HALF_EVEN);
}


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

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

BigDecimal b1 = new BigDecimal(Double.toString(

BigDecimal的加法溢出了

import java.math.BigInteger;
public class Main
{
public static void main(String[] args)
{
BigInteger a = new BigInteger("212112122212public static void main(String[] args) {
BigInteger bint = new BigInteger("10000000000000000000");
System.out.println(bint.add(new BigInteger("10000000000000000000")));
}

BigDecimal b1 = new BigDecimal("使用String类型。