Converting Integer to Long

Question

I need to get the value of a field using reflection. It so happens that I am not always sure what the datatype of the field is. For that, and to avoid some code duplication

Answer 1

No, you can't cast Integer to Long, even though you can convert from int to long. For an individual value which is known to be a number and you want to get the long value, you could use:

Number tmp = getValueByReflection(inv.var1(), classUnderTest, runtimeInstance);
Long value1 = tmp.longValue();

For arrays, it will be trickier...

Answer 2

A parser from int variables to the long type is included in the Integer class. Here is an example:

int n=10;
long n_long=Integer.toUnsignedLong(n);

You can easily use this in-built function to create a method that parses from int to long:

    public static long toLong(int i){
    long l;
    if (i<0){
        l=-Integer.toUnsignedLong(Math.abs(i));
    }
    else{
        l=Integer.toUnsignedLong(i);
    }
    return l;
}

Answer 3

Converting Integer to Long Very Simple and many ways to converting that
Example 1

 new Long(your_integer);

Example 2

Long.valueOf(your_integer); 

Example 3

Long a = 12345L;

Example 4
If you already have the int typed as an Integer you can do this:

Integer y = 12;
long x = y.longValue();

Answer 4

Simply:

Integer i = 7;
Long l = new Long(i);

Answer 5

If you know that the Integer is not NULL, you can simply do this:

Integer intVal = 1;
Long longVal = (long) (int) intVal

Answer 6

((Number) intOrLongOrSomewhat).longValue()