关于String类型，转换BigDecimal .并且BigDecimal 的乘法计算

//减法计算

BigDecimal insuranceAmt= BigDecimal.ZERO;

BigDecimal price_JQX = BigDecimal.ZERO;

BigDecimal price = insuranceAmt.subtract(price_JQX);

//乘法计算，保留两位小数,只舍去不入

1 BigDecimal price_bonus = price.multiply(new BigDecimal(0.94,new MathContext(2))).setScale(2, BigDecimal.ROUND_DOWN);

//加法运算

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();
    }

//字符串与BigDecimal的相互转换

BigDecimal b = new BigDecimal(columnValue);
//变成金钱格式,留   .0
DecimalFormat format = new DecimalFormat("0.0");
String floatString = format.format(b);

//String 转换 BigDecimal

String a = "1.1";  //字符串类型，必须是数字，否则会报错， java.lang.NumberFormatException 异常

System.out.println(new BigDecimal(a));