The default calculation in java does not support very precise decimal operations, but the method of the bigDecimal class can solve this problem.
Below is a tool class that I encapsulated in the project. For reference
/**
* High-precision computing tools
*
* @author Leon
* @version 2018/4/18 11:56
*/
public class ArithmeticUtil {
/**
* default divide scale
*/
private static final int DEFAULT_DIVIDE_SCALE = 10;
/**
*default add scale
*/
private static final int DEFAULT_ADD_SCALE = 4;
/**
*default subtract scale
*/
private static final int DEFAULT_SUB_SCALE = 4;
/**
* default multiplicative default
*/
private static final int DEFAULT_MULTI_SCALE = 10;
/**
* default scale
*/
private static final int DEFAULT_SCALE = 2;
/**
* private constructor
*/
private ArithmeticUtil(){}
/**
* Return the result of tow number divide by default scale
*
* @param arg1
* @param arg2
* @return
*/
public static double divide(double arg1, double arg2){
return divide(arg1, arg2, DEFAULT_DIVIDE_SCALE);
}
/**
* Return the result of two string number divide by scale
*
* @param arg1
* @param arg2
* @param scale
* @return
*/
public static double divide(double arg1, double arg2, int scale){
return divide(Double.toString(arg1), Double.toString(arg2), scale);
}
/**
* Return the result of two string number divide by default scale
*
* @param arg1
* @param arg2
* @return
*/
public static double divide(String arg1, String arg2){
return divide(arg1, arg2,DEFAULT_DIVIDE_SCALE);
}
/**
* Return the result of two string number divide by scale
*
* @param arg1
* @param arg2
* @param scale
* @return
*/
public static double divide(String arg1, String arg2, int scale){
BigDecimal var1 = new BigDecimal(arg1);
BigDecimal var2 = new BigDecimal(arg2);
return var1.divide(var2, scale, BigDecimal.ROUND_HALF_UP).doubleValue();
}
/**
* Return the result of two number multiplicative by default scale
*
* @param arg1
* @param arg2
* @return
*/
public static double multiply(double arg1, double arg2){
return multiply(arg1, arg2, DEFAULT_MULTI_SCALE);
}
/**
* Return the result of two number multiplicative by scale
*
* @param arg1
* @param arg2
* @return
*/
public static double multiply(double arg1, double arg2, int scale){
return multiply(Double.toString(arg1), Double.toString(arg2), scale);
}
/**
* Return the result two string number multiplicative by default scale
*
* @param arg1
* @param arg2
* @return
*/
public static double multiply(String arg1, String arg2){
return multiply(arg1, arg2, DEFAULT_MULTI_SCALE);
}
/**
* Return the result of two number multiplicative by scale
*
* @param arg1
* @param arg2
* @param scale
* @return
*/
public static double multiply(String arg1, String arg2, int scale){
BigDecimal var1 = new BigDecimal(arg1);
BigDecimal var2 = new BigDecimal(arg2);
return round(var1.multiply(var2).doubleValue(), scale);
}
/**
* Return the result of two number subtract by scale
*
* @param arg1
* @param arg2
* @param scale
* @return
*/
public static double subtract(double arg1, double arg2 ,int scale){
return subtract(Double.toString(arg1), Double.toString(arg2), scale);
}
/**
* Return the result of two number subtract by default scale
*
* @param arg1
* @param arg2
* @return
*/
public static double subtract(double arg1, double arg2){
return subtract(Double.toString(arg1), Double.toString(arg2), DEFAULT_SUB_SCALE);
}
/**
* Return the result of two number subtract by default scale
*
* @param arg1
* @param arg2
* @return
*/
public static double subtract(String arg1, String arg2){
return subtract(arg1, arg2, DEFAULT_SUB_SCALE);
}
/**
* Return the result of two number subtract by scale
*
* @param arg1
* @param arg2
* @param scale
* @return
*/
public static double subtract(String arg1, String arg2, int scale){
BigDecimal var1 = new BigDecimal(arg1);
BigDecimal var2 = new BigDecimal(arg2);
return round(var1.subtract(var2).doubleValue(), scale);
}
/**
* Return two number sum by the param scale value
*
* @param arg1
* @param arg2
* @param scale
* @return
*/
public static double add(double arg1, double arg2, int scale){
return add(Double.toString(arg1), Double.toString(arg2), scale);
}
/**
* Return two number sum by default add scale
*
* @param arg1
* @param arg2
* @return
*/
public static double add(double arg1, double arg2){
return add(Double.toString(arg1), Double.toString(arg2));
}
/**
* Return two number sum by default add scale
*
* @param arg1
* @param arg2
* @return
*/
public static double add(String arg1, String arg2){
return add(arg1, arg2, DEFAULT_ADD_SCALE);
}
/**
* Return two number sum by scale
*
* @param arg1
* @param arg2
* @param scale
* @return
*/
public static double add(String arg1, String arg2, int scale){
BigDecimal var1 = new BigDecimal(arg1);
BigDecimal var2 = new BigDecimal(arg2);
return round(var1.add(var2).doubleValue(), scale);
}
/**
* Return a result from arg1 by scale
*
* @param arg1
* @param scale
* @return
*/
public static double round(double arg1, int scale){
return round(Double.toString(arg1), scale);
}
/**
* Return result by scale
*
* @param arg1
* @param scale
* @return
*/
public static double round(String arg1, int scale){
if (scale < 0){
throw new IllegalArgumentException("The scale value must be an integer or zero");
}
BigDecimal var1 = new BigDecimal(arg1);
BigDecimal var2 = new BigDecimal(1);
return var1.divide(var2, scale, BigDecimal.ROUND_HALF_UP).doubleValue();
}
/**
* Return a result from arg1 by default scale
*
* @param arg1
* @return
*/
public static double round(double arg1){
return round(arg1, DEFAULT_SCALE);
}
}