方程输出为十进制，不是科学记数法

So I have this code:

所以我有这个代码:

public BigDecimal calculateEWT (BigDecimal amount, boolean vatInclusive, int scale)
{       
    if (isZeroTax())
        return Env.ZERO;

    BigDecimal rateTax = getRate().divide(ONEHUNDRED, 12, BigDecimal.ROUND_HALF_UP);
    BigDecimal rateEWT = getcus_tax_EWTRate().divide(ONEHUNDRED, 12, BigDecimal.ROUND_HALF_UP);
    rateTax = rateTax.add(Env.ONE);

    BigDecimal ewt = null;
    if (!vatInclusive) {
        BigDecimal base = amount.divide(rateTax, 12, BigDecimal.ROUND_HALF_UP);
        ewt = base.multiply(rateEWT);
        System.out.println("EWT VAT not inclusive: " + ewt);
    } else {
        BigDecimal base = amount.multiply (rateTax);
        ewt = base.multiply(rateEWT);
        System.out.println("EWT VAT inclusive: " + ewt);
    }
    BigDecimal finalEWT = ewt.setScale(scale, BigDecimal.ROUND_HALF_UP);
    System.out.println("Final EWT: " + finalEWT);
    return finalEWT;
}
public BigDe