Solve the problem of subtracting double type with errors __jmeter

Today, when writing a script, we found that the subtraction of the double type has an error with the actual result, such as: 19.9-9.9=9.9999999999999, instead of 10, after Baidu found that double subtraction will be converted to binary, because double valid digits are 16 bit This will result in a situation where the number of decimal places is not enough, in which case there will be error, the solution is to use BigDecimal, its effective length is long enough to store decimal digits so it can be used instead of double to subtraction, the following is the use of BigDecimal:

Serial number	Method	Type	Description
1	Public BigDecimal (double val)	Structure	Converts a double representation For BigDecimal
2	Public BigDecimal (int val)	Structure	Converts an int representation to a BigDecimal
3	Public BigDecimal (String val)	Structure	Represents a String Form conversion to BigDecimal
4	Public BigDecimal Add (BigDecimal augend)	Ordinary	Addition
5	Public BigDecimal Subtract (BigDecimal subtrahend)	Ordinary	Subtraction
6	Public BigDecimal Multiply (BigDecimal Multiplicand)	Ordinary	Multiplication
7	Public BigDecimal Divide (BigDecimal Divisor	Ordinary	Division

Add two double numbers

public static double Add (Double v1,double v2) {

BigDecimal B1 = new BigDecimal (v1.tostring ());

BigDecimal b2 = new BigDecimal (v2.tostring ());

Return B1.add (B2). Doublevalue ();

}

Subtract two double numbers

public static double sub (double v1,double v2) {

BigDecimal B1 = new BigDecimal (v1.tostring ());

BigDecimal b2 = new BigDecimal (v2.tostring ());

Return B1.subtract (B2). Doublevalue ();

}

Multiply two double numbers

public static double Mul (Double v1,double v2) {

BigDecimal B1 = new BigDecimal (v1.tostring ());

BigDecimal b2 = new BigDecimal (v2.tostring ());

Return b1.multiply (B2). Doublevalue ();

}

Divide two double numbers

public static double div (Double v1,double v2) {

BigDecimal B1 = new BigDecimal (v1.tostring ());

BigDecimal b2 = new BigDecimal (v2.tostring ());

Return B1.divide (B2,DEF_DIV_SCALE,BIGDECIMAL.ROUND_HALF_UP). Doublevalue ();

}

Divides two double numbers and preserves scale decimal places

public static double div (double v1,double v2,int scale) {

if (scale<0) {

throw New IllegalArgumentException (

"The scale must be a positive integer or zero");

}

BigDecimal B1 = new BigDecimal (v1.tostring ());

BigDecimal b2 = new BigDecimal (v2.tostring ());

Return B1.divide (B2,SCALE,BIGDECIMAL.ROUND_HALF_UP). Doublevalue ();

}

To rounding

BigDecimal B1 = new BigDecimal (d);
BigDecimal b2 = new BigDecimal (1);
Any number divided by 1 is the original number.
ROUND_HALF_UP is a constant of BigDecimal,
Represents an operation that is rounded
Return B1.divide (B2, Len,bigdecimal.
ROUND_HALF_UP). Doublevalue ();

}

More about BigDecimal usage See: http://www.apihome.cn/api/java/BigDecimal.html