Java将浮点数转换为整数

Question

I want to do an operation like this : if the given float numbers are like 1.0 , 2.0 , 3.0 , I want to save them to database as integer (1,2,3 ), if they are like 1.1 , 2.1 , ,3.44 , I save them as float. what's the best solution for this problem using java ? The corresponding field in database is type of varchar.

Answer 1

Just try int i = (int) f; .

EDIT : I see the point in the question. This code might work :

 int i = (int) f;
 String valToStore = (i == f) ? String.valueOf(i) : String.valueOf(f);

Answer 2

String result = "0";
if (floatVar == Math.floor(floatVar)) {
    result = Integer.toString((int) floatVar);
} else {
    result = Float.toString(floatVar);
}

The if-clause checks whether the number is a whole number - ie if it is equal to the result of rounding it down to the closest whole value.

But this is very odd requirement indeed, and perhaps you should reconsider the need for such a thing.

Answer 3

Seems like you want to save Floats with no trailing numbers as Integers, while saving those with significant trailing numbers as Floats. I would rather just save it all as Float to the DB, but it's your question so here's my answer:

/**
   * Method to determine if trailing numbers are significant or not. Significant
   * here means larger than 0
   * 
   * @param fFloat
   * @return
   */
  public static boolean isTrailingSignificant(Float fFloat)
  {
    int iConvertedFloat = fFloat.intValue();// this drops trailing numbers
    // checks if difference is 0
    return ((fFloat - iConvertedFloat) > 0);
  }

This is how you would use this method:

 Number oNumToSave = null;
if (isTrailingSignificant(fFloat))
{
  // save float value as is
  oNumToSave = fFloat;
}
else
{
  // save as int
  oNumToSave = fFloat.intValue();// drops trailing numbers      
}

After that, you can do the database operation using the variable oNumToSave.

Answer 4

Not sure this is the best solution, but you can try to write a method like this :

String convertToString(Float f) {
  if (f.toString().endsWith(".0"))
      return f.intValue().toString();
  else
      return f.toString();
}

Answer 5

Kotlin:

    val mAmount = 3.0
    val intAmount = mAmount.toInt()
    val amountToDisplay = if (intAmount.compareTo(mAmount) == 0) intAmount.toString() else java.lang.String.valueOf(mAmount)