how can I parse "30.0" or "30.00" to Integer?

Question

I using:

String str="300.0";
System.out.println(Integer.parseInt(str));

return an exception:

Exception in thread "main" java.lang.NumberFormatException: For input string: "300.0"

How can I parse this String to int?

thanks for help :)

Answer 1

Here's how you do it:

String str = "300.0";
System.out.println((int) Double.parseDouble(str));

The reason you got a NumberFormatException is simply that the string ("300.00", which is a floating point number) could not be parsed as an integer.

---

It may be worth mentioning, that this solution prints 300 even for input "300.99". To get a proper rounding, you could do

System.out.println(Math.round(Double.parseDouble("300.99")));  // prints 301

Answer 2

I am amazed no one has mentioned BigDecimal.

It's really the best way to convert string of decimal's to int.
Josuha Bloch suggest using this method in one of his puzzlers.

Here is the example run on Ideone.com

class Test {
  public static void main(String args[]) {
    try {
        java.math.BigDecimal v1 = new java.math.BigDecimal("30.0");
        java.math.BigDecimal v2 = new java.math.BigDecimal("30.00");            
      System.out.println("V1: " + v1.intValue() + " V2: " + v2.intValue());
    } catch(NumberFormatException npe) {
      System.err.println("Wrong format on number");
    }
  }
}