DecimalFormat

public class TestDemo {
    public static void main(String[] args) {
        String format = new DecimalFormat("##0.#######").format(10.000001);
        System.out.println(format);

        DecimalFormat f = new DecimalFormat("#,##0.00");
        f.setRoundingMode(RoundingMode.HALF_UP);
        String format1 = f.format(1.126);
        System.out.println(format1);
    }
}

output:
1.12

DecimalFormat f = new DecimalFormat("#,##0.00");
f.setRoundingMode(RoundingMode.HALF_UP);
double d = 1.125;
System.out.println(f.format(d)); // 输出 1.12

d = 1.135;
System.out.println(f.format(d)); // 输出 1.14

public static float div(int v1, int v2, int scale) { 
  if (v2 != 0) { 
    BigDecimal b1 = new BigDecimal(Double.toString(v1)); 
    BigDecimal b2 = new BigDecimal(Double.toString(v2)); 
    return b1.divid(b2,scale,BigDecimal.ROUND_HALF_UP).doubleValue(); 
  } else { 
      return 0; 
  } 
}

//scale表示保留几位小数