CODEWITHSUNDEEP
javamysqljdbc
EG3542
EG3542

Reputation: 9

JDBC Error After end of result set

I have created a method which should return a cell from my database (it's a varchar variable) and assign it to a String. Another method is then called that takes that String and assigns variables to a User object which is then added to an array list. The SQL query statement works fine in PHPMyAdmin, but in Java the method runs until just after System.out.println("Getting followers...");

Then for some reason it stops working. I don't understand it because I have used the code from this method to retrieve different variables in other parts of the program without any problems, but whenever I try to get this one variable from the database, it fails to work properly.

Thanks in advance for all your help.

public ArrayList<User> returnFollowers(){

    ArrayList<User> userArray = new ArrayList<User>();

    User user = new User();

    try{
        Class.forName("com.mysql.jdbc.Driver");
        statement = connection.createStatement();
        result = statement.executeQuery("SELECT Follower FROM User_Followers WHERE Username = 'Apple123'");

        if(!result.next()){

            System.out.println("No results found");
        }
        else{
            while(result.next()){
            }
                System.out.println("Getting followers...");
                String userID = result.getString("Follower");

                user.createUser(userID);
                userArray.add(user);
            }
        }
    catch(ClassNotFoundException error){
        System.out.println("Error: " + error.getMessage());
    }
    catch(SQLException error){
        System.out.println("Error " + error.getMessage());
    }       
    finally{
        if(connection != null){
            try{
                connection.close();
            }
            catch(SQLException ignore){

            }
        }

        if(statement != null){
            try{
                statement.close();
            }
            catch(SQLException ignore){
            }

        }
    }

    return userArray;

}

Upvotes: 0

Views: 71

Answers (2)

Braj
Braj

Reputation: 46871

  • First while loop is empty

  • Second The problem is with result.next() that you have already called in if clause.

    Now you are calling result.next() again in while clause hence first record is already skipped.

    change while loop in do-while in this case.

Do in this way:

   if(!result.next()){
        System.out.println("No results found");
   }else{
        do{
            System.out.println("Getting followers...");
            String userID = result.getString("Follower");

            user.createUser(userID);
            userArray.add(user);
        }while(result.next());
   }

Read more...

Upvotes: 2

Reimeus
Reimeus

Reputation: 159864

You're calling result.getString("Follower") outside the scope of the while loop so there are no more records available. It's probably better just to use a single while loop here

Upvotes: 0

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