Insert operation taking null values in java swings

Question

i have a mysql database named tutorial which contain a table "devices", i have a swing programme, which insert a row to the table through text box. it works fine for inserting a row, but when i leave the textbox blank and click "ok" button, an empty column is added into the row.how to avoid adding empty row.and avoid adding the row even if a single textbox is empty. i have already defined not null constraint in mysql.plz help.

here is my code:

jb.addActionListener(new ActionListener(){

     public void actionPerformed( ActionEvent e ) {
         try {
                Class.forName("com.mysql.jdbc.Driver");
                System.out.println("Driver loading success!");
                String url = "jdbc:mysql://localhost:3306/tutorial";
                String name = "root";
                String password = "ranjini123";
        try {
                java.sql.Connection con = DriverManager.getConnection(url, name, password);
                System.out.println("Connected.");
                String text1=jt1.getText();
                String text2=jt2.getText();
                String text3=jt3.getText();
                String text4=jt4.getText();
                String text5=jt5.getText();
                ps = con.prepareStatement (
                    "INSERT INTO devices (asset_id,name,project,emp_id,emp_name) VALUES(?,?,?,?,?)");
                  try{ 

                          ps.setString (1, text1);
                          ps.setString (2, text2);
                          ps.setString (3, text3);
                          ps.setString (4, text4);
                          ps.setString(5,text5);                                      
                          ps.executeUpdate(); 
                          JOptionPane.showMessageDialog(null,"new device added");


                   }
                   catch(NullPointerException n)
                   {
                       n.printStackTrace();
                   }
            }
            catch (SQLException n)
            {
                n.printStackTrace();
            }
         }
            catch(Exception n) 
            {
                n.printStackTrace();
            }   
     }

});

In the ActionListener for the button you need to check the values of the text field to make sure it contains a value. If not you display a JOptionPane with an error message and set focus back on the text field. — camickr
– camickr, Commented Nov 25, 2013 at 5:00

MadProgrammer · Accepted Answer · 2013-11-25 05:02:46Z

2

Basically, you'll want to check to see if any of the text fields are null or 0 in length. You need to check to see if they are null here, because it could throw a NullPointerException otherwise...

String text1=jt1.getText();
String text2=jt2.getText();
String text3=jt3.getText();
String text4=jt4.getText();
String text5=jt5.getText();

if (text1 != null && !text1.trim().isEmpty() &&
    text2 != null && !text2.trim().isEmpty() &&
    text3 != null && !text3.trim().isEmpty() &&
    text4 != null && !text4.trim().isEmpty() &&
    text5 != null && !text5.trim().isEmpty()) {
     //... Do insert
 } else {
     // Deal with the fact that one or more of the values are invalid
 }

answered Nov 25, 2013 at 5:02

MadProgrammer

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