Java中Double类型的加减 - Java

前提: Double类型的加减直接进行加减将会损失精度, 这样就会造成bug, 正规应该使用BigDecimal类进行运算

使用平常加减出现的bug:

解决方法:

public static Double BigDecimalCal(Double d1,String operation,Double d2){
        BigDecimal bd = new BigDecimal("0");
        if(d1!=null && d2!=null){
            if("+".equals(operation)){
                bd = new BigDecimal(String.valueOf(d1)).add(new BigDecimal(String.valueOf(d2)));
            }else if("-".equals(operation)){
                bd = new BigDecimal(String.valueOf(d1)).subtract(new BigDecimal(String.valueOf(d2)));
            }else if("*".equals(operation)){
                bd = new BigDecimal(String.valueOf(d1)).multiply(new BigDecimal(String.valueOf(d2)));
            }else if("/".equals(operation)){
                bd = new BigDecimal(String.valueOf(d1)).divide(new BigDecimal(String.valueOf(d2)),6,RoundingMode.HALF_UP);
            }
        }
        return bd.doubleValue();
    }
    
    public static String BigDecimalCal(String d1,String operation,String d2){
        BigDecimal bd = new BigDecimal("0");
        if(d1!=null && d2!=null){
            if("+".equals(operation)){
                bd = new BigDecimal(d1).add(new BigDecimal(d2));
            }else if("-".equals(operation)){
                bd = new BigDecimal(d1).subtract(new BigDecimal(d2));
            }else if("*".equals(operation)){
                bd = new BigDecimal(d1).multiply(new BigDecimal(d2));
            }else if("/".equals(operation)){
                bd = new BigDecimal(d1).divide(new BigDecimal(d2),6,RoundingMode.HALF_UP);
            }
        }
        return bd.toString();
    }

应用:

Double rate1 = Double.parseDouble(rowData[1]);
  Double rate2 = Double.parseDouble(rowData[2]);
  // rate1*rate2, 如果是rate1-rate2, 只需改为 '-' 即可
  Double depX1 = PubFun.BigDecimalCal(rate1, "*", rate2);