java四舍五入、保留n位小数

public static void main(String[] args) { double x = 1103.41903333; DecimalFormat df5 = new DecimalFormat("0.00"); System.out.println(df5.format(x)); // 四舍五入 MathContext v = new MathContext(2, RoundingMode.HALF_DOWN); double e = 0.0000361328125; e = 0.37/1024; BigDecimal d = new BigDecimal(e, v); System.out.println(d.doubleValue()); }

 

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得到的结果是1.6。要输出是保留0，即1.60

 

java.text.NumberFormat formater = java.text.DecimalFormat.getInstance(); formater.setMaximumFractionDigits(2); formater.setMinimumFractionDigits(2); System.out.println(formater.format(1.6)); System.out.println(formater.format(300));

 

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BigDecimal mData = new BigDecimal("42674.625").setScale(2, BigDecimal.ROUND_HALF_UP);
        System.out.println("mData=" + mData);//mData=42674.63