double 的Bigdecimal精度

double sd = (double)8/(double)261;
BigDecimal bgitem = BigDecimal.valueOf(sd);
double fitem = Math.round(bgitem.setScale(4, BigDecimal.ROUND_HALF_UP).doubleValue()10000)0.01 ;

                    DecimalFormat    df   = new DecimalFormat("######0.00");
                    String st = df.format(fitem);