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Tiberiu Dorian Moşescu
Tiberiu Dorian Moşescu

Reputation: 398

Convert Object to String in java

What is the best way to convert an object I get from a database to String in Java? For example, I have a field which returns a BigDecimal. How do I convert it to String, while keeping it as null (primitive), if it comes back null? I was using String.valueOf(obj), but this actually transforms it to the String representation "null".

Upvotes: 0

Views: 8923

Answers (3)

Dennis van Opstal
Dennis van Opstal

Reputation: 1338

I think casting the Object to a String or indeed using String.valueOf(obj) would work, but just do a check if the value isn't null, like:

if(obj == null) {
   //Do something
}
else {
   String s = (String) obj;
}

Upvotes: 0

h2ooooooo
h2ooooooo

Reputation: 39532

As you've noticed you get the string "null" instead of an actual null value. This is by design:

Returns:
if the argument is null, then a string equal to "null"; otherwise, the value of obj.toString() is returned.

That said, you could just check if it's null before converting it:

import java.math.BigDecimal;

class Main
{
    public static void main (String[] args)
    {
        BigDecimal foo = new BigDecimal(1.0);
        BigDecimal bar = null;

        // if the value isn't NULL, use String.valueOf, else use NULL
        String fooString = foo != null ? String.valueOf(foo) : null;
        String barString = bar != null ? String.valueOf(bar) : null;

        System.out.println(fooString == null ? "REALNULL" : "\"" + fooString + "\"");
        System.out.println(barString == null ? "REALNULL" : "\"" + barString + "\"");
    }
}

Output:

"1"
REALNULL

DEMO

Upvotes: 2

Awais Ahmad
Awais Ahmad

Reputation: 427

this is something you can do for converting those values into string values.

decimal dValue = 59.24;
String sValue = dValue+"";

Upvotes: 0

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