Cast a Null String into Integer

Question

Is there any way to cast a null to Integer. The null is actually a String, which i am passing in my service layer that accepts it as an Integer. So, whenever i try to cast a

Answer 1

You cannot cast from String to Integer.
Java data types are of two kinds: primitive and reference. Primitive types are: byte, short, int, long, char, float, double. The reference types are: class, interface, array.
byte -> short -> int -> long -> float -> double. is allow, Or The casting may be of its own type or to one of its subclass or superclasss types or interfaces.
So this is a ex. of function take a look

    public int getInteger(String no) {
    if (no != null) {
        return Integer.parseInt(no); //convert your string into integer 
    } else {
        return 0; // or what you want to return if string is Null
    }
}

Answer 2

Try below code:application will return 0 if the string is null else it will parse the string to int if string contains a number alone..

Code:

(str.equals("null")?0:Integer.parseInt(str))

Answer 3

If you are sure you only have to handle nulls,

int i=0;
i=(str==null?i:Integer.parseInt(str));
System.out.println(i);

for non integer strings it will throw Numberformat exception

Answer 4

String s= "";  
int i=0;
i=Integer.parseInt(s+0);
System.out.println(i);

Try this

Answer 5

What about this ?

private static void castTest() {
    System.out.println(getInteger(null));
    System.out.println(getInteger("003"));
    int a = getInteger("55");
    System.out.println(a);
}

private static Integer getInteger(String str) {
    if (str == null) {
        return new Integer(0);
    } else {
        return Integer.parseInt(str);
    }
}

Answer 6

You cannot cast from String to Integer. However, if you are trying to convert string into integer and if you have to provide an implementation for handling null Strings, take a look at this code snippet:

String str = "...";
// suppose str becomes null after some operation(s).
int number = 0;
try
{
    if(str != null)
      number = Integer.parseInt(str);
}
catch (NumberFormatException e)
{
    number = 0;
}