给你一个方法:
double div(double v1,double v2)
{
return div(v1,v2,3);
}
double div(double v1,double v2,int scale)
{
if(scale<0)
{
throw new IllegalArgumentException("The scale must be a positive integer or zero");
}
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.divide(b2,scale,BigDecimal.ROUND_HALF_UP).doubleValue();
}
double round(double v,int scale)
{
if(scale<0)
{
throw new IllegalArgumentException( "The scale must be a positive integer or zero");
}
BigDecimal b = new BigDecimal(Double.toString(v));
BigDecimal one = new BigDecimal("1");
return b.divide(one,scale,BigDecimal.ROUND_HALF_UP).doubleValue();
}
使用之前先加入java.math.BigDecimal类