string小数点取后n位_Java取小数点后两位(N位)的方法归纳

Ⅰ

java.text.DecimalFormat df = new java.text.DecimalFormat("#0.##");

double d=3.14159;

System.out.println(df.format(d));

Ⅱ

java.math.BigDecimal bd = new java.math.BigDecimal("3.14159265");

bd = bd.setScale(2,BigDecimal.ROUND_HALF_UP);

Ⅲ

class Test{

public static void main(String se77en[]){

double ret = convert(3.14159);

System.out.println(ret);

}

static double convert(double value){

long l1 = Math.round(value*100); //四舍五入

double ret = l1/100.0; //注意：使用100.0而不是100

return ret;

}

}

Ⅳ

double d = 3.14159;

d = (double)((int)(d*100+0.5))/100;