Java parsing a string into an int, then a null

Question

Got this code:

            System.out.println("Introduce salary: ");
            Scanner alpha8 = new Scanner(System.in);
            String salary = alpha8.nextLine();
            int salaryNew = 0;
            if(salary .isEmpty()){
                salary = null;
            }else{
                salaryNew = Integer.parseInt(salary);
            }

How can i make this to output only 1 variable from the IF? Because if the introduced value is null (blank space from scanner, like enter) sets salary to null wich i use later on.

The thing is that i either need a "null" or an "int value".

In the "else" i cannot do this:

salary = Integer.parseInt(salary);

because id get an error, neither i can parse int into to null.

And this methodto convert dates:

public static Date changeDate(String introducedDate) throws ParseException {
    SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");
    java.util.Date sqlDate = sdf.parse(introducedDate);
    java.sql.Date newSqlDate= new java.sql.Date(sqlDate.getTime());
    return newSqlDate;
}

If introducedDate is null it will throw an exception, how can i change that method to return NULL if introduced date is NULL too?

if(introduced date == null){return null} like this? but there would be 2 returns in that method coz there muset be an else too — Alpha2k
– Alpha2k, Commented Sep 18, 2014 at 19:23

azurefrog · Accepted Answer · 2014-09-18 19:37:35Z

2

Part 1

The thing is that i either need a "null" or an "int value".

If you want to have an integer value which is nullable, use the wrapper class Integer:

Integer salaryNew = null;
if (!salary.isEmpty()) {
    salaryNew = Integer.parseInt(salary);
}

Part 2

If introducedDate is null it will throw an exception, how can i change that method to return NULL if introduced date is NULL too?

You need to check the value of the parameter before you do any work on it (See @nem's answer, since he beat me to that half).

edited Sep 18, 2014 at 19:37

answered Sep 18, 2014 at 19:24

azurefrog

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7 Comments

Alpha2k Over a year ago

strange, getting null pointer exception, i must set that salaryNew to an entity, like employee.setSalary(salaryNew) and getting null pinter lol. Works with date but not with salary

azurefrog Over a year ago

@Alpha2k I would expect that the salary type inside the employee is int, which as you've already discovered cannot be assigned a null value. When the compiler tries to unbox the null, it'll throw a NPE. Do you really need salaryNew to be nullable?

Alpha2k Over a year ago

even tough i changed the employee to Integer salary i still get a null pointer in the prepared statement: pstmt.setInt(7, employee.getSal());

azurefrog Over a year ago

@Alpha2k what value do you expect to be written to the database is the salary is null? If the database is expecting a number, you'll need to give it one. Do you have some sort of "no salary here" error code you can enter? If so, you can check for a null parameter in setSal() and assign that error value.

Alpha2k Over a year ago

yea kinda need it nullable max for example when searching with ranges. User may define lowestPrice but if highestPrice is not introduced by user is considered as null.

|

nem035 · Accepted Answer · 2014-09-18 19:24:21Z

1

Check out @azurefrog's answer for your first question.

If introducedDate is null it will throw an exception, how can i change that method to return NULL if introduced date is NULL too?

public static Date changeDate(String introducedDate) throws ParseException {
    if(introducedDate == null) {  // ADD THIS CHECK
        return null;
    }
    SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");
    java.util.Date sqlDate = sdf.parse(introducedDate);
    java.sql.Date newSqlDate= new java.sql.Date(sqlDate.getTime());
    return newSqlDate;
}

answered Sep 18, 2014 at 19:24

nem035

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2 Comments

azurefrog Over a year ago

Is there a way to combine our answers...? ;-)

nem035 Over a year ago

@azurefrog i don't think so haha then again, we both got an upvote for a half-answer so I guess that is a combination haha

Moni · Accepted Answer · 2014-09-18 19:59:32Z

0

you can do -

if(salary != null && ! salary.isEmpty() )
{
     return Integer.parseInt(salary);
}else{
      return null;
}

for your second part add this if condition before doing any date format-

   if(introducedDate == null) { 
        return null;
    }

answered Sep 18, 2014 at 19:59

Moni

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