java——double数据精度问题

代码：使用BigDecimal来代替double

public class BigDecimalUtil {
     public static BigDecimal add(double v1,double v2){
         BigDecimal b1 = new BigDecimal(Double.toString(v1));
         BigDecimal b2 = new BigDecimal(Double.toString(v2));
         return b1.add(b2);
     }
     public static BigDecimal sub(double v1,double v2){
         BigDecimal b1 = new BigDecimal(Double.toString(v1));
         BigDecimal b2 = new BigDecimal(Double.toString(v2));
         return b1.subtract(b2);
     }
     public static BigDecimal mul(double v1,double v2){
         BigDecimal b1 = new BigDecimal(Double.toString(v1));
         BigDecimal b2 = new BigDecimal(Double.toString(v2));
         return b1.multiply(b2);
     }
     public static BigDecimal div(double v1,double v2){
         BigDecimal b1 = new BigDecimal(Double.toString(v1));
         BigDecimal b2 = new BigDecimal(Double.toString(v2));
         return b1.divide(b2,2,BigDecimal.ROUND_HALF_UP);//四舍五入,保留2位小数
    }
 }

 

double测试示例：

public class BigDecimalTest{
     @test
     public void test1(){
         System.out.println(0.05+0.01);
         System.out.println(1.0-0.42);
         System.out.println(4.015*100);
         System.out.println(123.3/100);
     }
 }

//运行结果
//0.060000000000005
 //0.57000000000000001
 //401.499999999999994
 //1.2329999999999999