CODEWITHSUNDEEP
javamysqljdbcarraylist
Gipsy
Gipsy

Reputation: 265

getting elements from mysql table to arraylist

i have an ArrayList that looks like this: 

[
1 2011-05-10  1  22.0, 
2 2011-05-10  2  5555.0, 
3 2011-05-11  3  123.0, 
4 2011-05-11  2  212.0, 
5 2011-05-30  1  3000.0, 
6 2011-05-30  1  30.0, 
7 2011-06-06  1  307.0, 
8 2011-06-06  1  307.0, 
9 2011-06-06  1  307.0, 
10 2011-06-08  2  3070.0, 
11 2011-06-03  2  356.0, 
12 2011-05-10  2  100.0, 
13 2011-05-30  1  3500.0, 
14 2011-05-10  3  1000.0, 
15 2011-05-10  3  1000.0, 
16 2011-05-07  1  5000.0, 
17 2011-05-07  4  500.0, 
18 2011-08-07  3  1500.0, 
19 2011-08-08  6  11500.0, 
20 2011-08-08  4  11500.0, 
21 2011-08-08  7  11500.0, 
22 2011-06-07  8  3000.0]

Here is the code how i got this arraylist: 

@Override
    public ArrayList<Expenses> getExpenses() {
        ArrayList<Expenses> expenses = new ArrayList<Expenses>();
        try {
            Statement stmt = myConnection.createStatement();
            ResultSet result = stmt.executeQuery("SELECT * FROM expenses");
            while(result.next()){

                Expenses expense = new Expenses();
                expense.setNum(result.getInt(1));
                expense.setPayment(result.getString(2));
                expense.setReceiver(result.getInt(3));
                expense.setValue(result.getDouble(4));

                expenses.add(expense);

                }
        }
            catch (SQLException e){
                 System.out.println(e.getMessage());
             }
        return expenses;
    }

but what i want to get to an arraylist so that each element of array wasn't the line of the table (what i have now), but every individual element of the table should be the element of array ( [1, 2011-05-10, 1, 22.0, 2, 2011-05-10, 2, 5555.0, 3, 2011-05-11, 3, 123.0,]. Can anyone help me with that?

Upvotes: 1

Views: 16812

Answers (3)

kgiannakakis
kgiannakakis

Reputation: 104196

The only way you could do add into an ArrayList elements of different type, will be to treat them as general objects. However the code you already have is much superior.

@Override
public ArrayList<Object> getExpenses() {
    ArrayList<Object> expenses = new ArrayList<Object>();
    try {
        Statement stmt = myConnection.createStatement();
        ResultSet result = stmt.executeQuery("SELECT * FROM expenses");
        while(result.next()) {

            expenses.add(new Integer(result.getInt(1)));

            expenses.add(result.getString(2));
            expenses.add(new Integer(result.getInt(3)));
            expenses.add(result.getDouble(4));
        }
    }
    catch (SQLException e) {
        System.out.println(e.getMessage());
    }
    return expenses;
}

Upvotes: 6

NPE
NPE

Reputation: 500913

Since you say in the comments that you're looking to get an ArrayList of Strings, the following should work:

@Override
public ArrayList<String> getExpenses() {
    ArrayList<String> expenses = new ArrayList<String>();
    try {
        Statement stmt = myConnection.createStatement();
        ResultSet result = stmt.executeQuery("SELECT * FROM expenses");
        while (result.next()) {
            expenses.add(result.getString(1));
            expenses.add(result.getString(2));
            expenses.add(result.getString(3));
            expenses.add(result.getString(4));
        }
    }
    catch (SQLException e) {
        System.out.println(e.getMessage());
    }
    return expenses;
}

The JDBC spec mandates (in Appendix B) that most SQL types -- including all types that are used here -- can be retrieved as strings using Statement.getString().

P.S. It is considered good practice to close each JDBC statement as soon as you're done with it. This is commonly done in a finally block (or in Java 7, using the try-with-resources construct). See https://stackoverflow.com/a/10514079/367273

Upvotes: 2

Rizstien
Rizstien

Reputation: 802

@Override
public ArrayList<String> getExpenses() {
    ArrayList<String> expenses = new ArrayList<String>();
    try {
        Statement stmt = myConnection.createStatement();
        ResultSet result = stmt.executeQuery("SELECT * FROM expenses");
        while(result.next()){

            String expense = null;
            setExpense(result.getInt(1).toString());
expenses.add(getExpense());                
setExpense(result.getString(2));
expenses.add(getExpense());                
setExpense(result.getInt(3).toString());
expenses.add(getExpense());                
setExpense(result.getDouble(4).toString());
expenses.add(getExpense());                


            }
    }
        catch (SQLException e){
             System.out.println(e.getMessage());
         }
    return expenses;
}
// make getter setters of expense accordingly

Upvotes: 1

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