数学运算Java工具类
jopen
11年前
import java.math.BigDecimal; public class NumberUtil { private static final int DEFAULT_DIV_SCALE = 10; /** * 相加 * @param v1 * @param v2 * @return double */ 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(); } /** * 相减 * @param v1 * @param v2 * @return */ 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(); } /** * 相乘 * @param v1 * @param v2 * @return */ 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(); } /** * 相除 * @param v1 * @param v2 * @return double */ 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 void main(String[] args) { System.out.println(2.21 - 2); System.out.println(7 * 0.8); System.out.println(subtract(312.21, 312)); System.out.println(multiply(7, 0.8)); } }