Java08-BigDecimal类的常用方法

金额计算不能用double，金额计算必须用BigDecimal,

import java.math.BigDecimal;
import java.math.RoundingMode;

public class test_BigDecimal {
    public static void main(String[] args) {
        BigDecimal a = new BigDecimal("12.1");
        BigDecimal b = new BigDecimal("13.1");
        
        // 加法
        BigDecimal c = a.add(b);
        System.out.println("加法add：   " + c);
        
        // 减法
        System.out.println("减法subtract：   " + a.subtract(b));
        
        // 乘法
        System.out.println("乘法multiply：   " + a.multiply(b));
        
        // 除法-保留小数点后3位
        System.out.println("除法divide:   " + a.divide(b, 3, RoundingMode.HALF_UP));
        
        // 2个数相比较-1: less than, 0:equal to, 1: greater than
        System.out.println("compareTo:   " +a.compareTo(b));
        
        //true if and only if the specified Object is a BigDecimal whose value and scale are equal to this BigDecimal's.
        System.out.println("equals:   " +a.equals(b));
        
        //Returns the string 
        System.out.println("toString:   " +a.toString());
        
        //Converts this BigDecimal to a BigInteger
        System.out.println("toBigInteger:   " +a.toBigInteger());
       

    }

}