CODEWITHSUNDEEP
javanumberformatexception
user1608396
user1608396

Reputation:

Get an exception once divide two values

I am retrieving two values from a database, and need to divide them, but it gives me null pointer exception on line 1 and 2

1    int value1 = Integer.parseInt(rs.getString("value1"));
2    int value2 = Integer.parseInt(rs.getString("value2"));
3    double result = (double)value1/value2;


Error 

 java.lang.NumberFormatException: null
at java.lang.Integer.parseInt(Integer.java:417)
at java.lang.Integer.parseInt(Integer.java:499)

Upvotes: 0

Views: 399

Answers (4)

MadProgrammer
MadProgrammer

Reputation: 347314

You can do...

double result = 0;

String value1 = rs.getString("value1");
String value2 = rs.getString("value2");
if (value1 != null && value2 != null) {
    try {
        result = (double)(Integer.parseInt(value1) / (double)Integer.parseInt(value2))
    } catch (NumberFormatException exp) {
      // Handle or re-throw exception...
    }
}
return result;

Or, if the column values are actually numbers...

double result = 0;

int value1 = rs.getInt("value1");
int value2 = rs.getInt("value2");

if (result2 > 0) {
    result = (double)value1 / (double)value2;
}
return result;

Or, which might be simpler

double result = 0;

int value1 = rs.getDouble("value1");
int value2 = rs.getDouble("value2");

if (result2 > 0) {
    result = value1 / value2;
}
return result;

Upvotes: 0

Nandkumar Tekale
Nandkumar Tekale

Reputation: 16158

You can parse only integer values which are in the form of Strings. For e.g. :

 int i = Integer.parseInt("20");
 int j = Integer.parseInt("NaN"); // throws NumberFormatException

Also, you should check values for null to avoid NPE as :

int v1=0, v2=0;
String value1 = rs.getString("value1");
if(value1  != null) {
    v1 = Integer.parseInt(value1);
}
String value2 = rs.getString("value2");
if(value1  != null) {
    v2 = Integer.parseInt(value2);
}

Upvotes: 0

Ankit HTech
Ankit HTech

Reputation: 1893

int value1 = Integer.parseInt(rs.getString("value1"));
int value2 = Integer.parseInt(rs.getString("value2"));

this line must be giving null thats why its giving null pointer exception

Upvotes: 0

Rohit Jain
Rohit Jain

Reputation: 213351

That is because, you are getting a null value from your database, that you cannot pass to Integer.parseInt().

If one of the res.getString("value1");, or res.getString("value2") is null, you will get an exception.

A better way is to wrap that conversion around try-catch block, and in catch block print the value of res.getString("value1"); to check the actual value returned.

EDIT: -

Of course, you can also first print the value returned before you convert it to integer to find if that is null or not.

Upvotes: 1

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