How to check whether a int is not null or empty

Question

I really dont know if this is possible or not  But I am strucking in a place where I want to check an int value is null or not  to call different methods   Is there any way to do it   Actually  variable comes from a browser with a null value  I cannot change the int declaration to Integer  Because it has it own consequences   Any suggestions

User · Answer

if your int variable is declared as a class level variable  instance variable  it would be defaulted to 0  But that does not indicate if the value sent from the client was 0 or a null  may be you could have a setter method which could be called to initialize set the value sent by the client  then you can define your indicator value   may be a some negative value to indicate the null

User · Answer

public class Demo       private static int i      private static Integer j      private static int k   -1       public static void main String   args            System out println i     j     k                OutPut  0 null -1

User · Answer

int variables can t be null  If a null is to be converted to int  then it is the converter which decides whether to set 0  throw exception  or set another value  like Integer MIN VALUE   Try to plug your own converter

User · Answer

I think you can initialize the variables a value like -1  because if the int type variables is not initialized it can t be used  When you want to check if it is not the value you want you can check if it is -1

User · Answer

int cannot be null  If you are not assigning any value to int default value will be 0  If you want to check for null then make int as Integer in declaration  Then Integer object can be null  So  you can check where it is null or not  Even in javax bean validation you won t be able to get error for  NotNull annotation until the variable is declared as Integer

User · Answer

I think you are asking about code like this   int  count    request getParameter  counter      null    0   Integer parseInt request getParameter  counter

User · Answer

An integer can t be null but there is a really simple way of doing what you want to do  Use an if-then statement in which you check the integer s value against all possible values  Example  int x      Some Code     if  x  lt   0    x  gt  0          What you want the code to do if x has a value   else          What you want the code to do if x has no value     Disclaimer  I am assuming that Java does not automatically set values of numbers to 0 if it doesn t see a value

User · Answer

Possibly browser returns String representation of some integer value  Actually int can t be null   May be you could check for null  if value is not null  then transform String representation to int

[java] How to check whether a int is not null or empty?

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