java——double數據精度問題

代碼：使用BigDecimal來代替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);//四捨五入,保留2位小數
 } }

 

double測試示例：

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); } }//運行結果//0.060000000000005 //0.57000000000000001 //401.499999999999994 //1.2329999999999999