Existing String to Double

Question

How can I change existing string into double. I have code like this declared as string but in reality its getting number from the database.. I was doing sting to number conversi

Answer 1

Double is immutable and must be constructed with a value (there is not a no-arg constructor): http://download.oracle.com/javase/1.4.2/docs/api/java/lang/Double.html

Answer 2

Just initialize it in your declaration, and remove the line where you set it to a new object. Take a look at this.

Answer 3

try {
  double d = Double.parseDouble(str);
  Double D = new Double(d);
}
catch( NumberFormatException e ) {
   // input cleansing
   // thou shalt not fail silently
}

Reference:

Double.parseDouble

Answer 4

I don't quite get your problem, but here are a few notes:

• you can create a double by simple declaring double d = 0. Or new Double(0) (passing the double value as argument)
• if you want to convert from string to double, use Double.parseDouble(string)