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Thread: Using method in Eclipse IDE

  1. #1
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    Default Using method in Eclipse IDE

    Hi, I would like to seek for help because right now I am very confused about why my code is not working..

    The function of my code will add records in my database (MySQL), Swing components of my frame..

    btnUserAdd = jButton
    txtUname, txtPword, txtLname, txtFname, txtMname, txtEmpNo = jTextField
    cbAccType = jComboBox
    EmpNo, Uname, Pword, Lname, Fname, Mname, AccType = MySQL fields

    I created a method to be called when btnUserAdd is clicked. here is the code for the method:

    public void UserAdd(){

    String sql = "SELECT * FROM User WHERE Uname = ? and EmpNo = ?";

    try {

    pst = conn.prepareStatement(sql);
    pst.setString(1, txtUname.getText().toString());
    pst.setString(2, txtEmpNo.getText().toString());
    rs = pst.executeQuery();

    if (rs.next()){

    JOptionPane.showMessageDialog(null, "Record Exists! Please Try Again.");
    txtUname.requestFocus();
    cbAccType.setSelectedItem("Operator");
    UserClear();

    }
    else {

    try {

    String sql1 = "INSERT INTO user (EmpNo, Uname, Pword, Lname, Fname, Mname, AccType)" + "VALUES (?, ?, ?, ?, ?, ?, ?)";
    String cb1 = cbAccType.getSelectedItem().toString();

    pst = conn.prepareStatement(sql1);
    pst.setString(1, txtEmpNo.getText());
    pst.setString(2, txtUname.getText());
    pst.setString(3, txtPword.getText());
    pst.setString(4, txtLname.getText());
    pst.setString(5, txtFname.getText());
    pst.setString(6, txtMname.getText());
    pst.setString(7, cb1);
    pst.execute();

    JOptionPane.showMessageDialog(null, "Record Added!");

    }
    catch (Exception e){

    JOptionPane.showMessageDialog(null, e);

    }

    }

    }
    catch (Exception e){

    JOptionPane.showMessageDialog(null, e);

    }

    }

    then here is the code inside the btnUserAdd:

    btnUserAdd.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent evt) {

    if (txtUname.getText().trim().equals("")||txtPword.ge tText().trim().equals("")||txtEmpNo.getText().trim ().equals("")||txtLname.getText().trim().equals("" )){

    JOptionPane.showMessageDialog(null, "Please Enter a Username, Password and Employee No, Try Again!");

    if (txtUname.getText().trim().equals("")){

    txtUname.requestFocus();

    }
    else if (txtPword.getText().trim().equals("")){

    txtPword.requestFocus();

    }
    else if (txtLname.getText().trim().equals("")){

    txtLname.requestFocus();

    }
    else if (txtEmpNo.getText().trim().equals("")){

    txtEmpNo.requestFocus();

    }

    }
    else{

    UserAdd();


    }

    }
    });

    the error is that it does not add the record it will display JAVA.LANG.NULLPOINTEREXCEPTION...

    please help me with my problem..


  2. #2
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    Default Re: Using method in Eclipse IDE

    Welcome to the forum! Please read this topic to learn how to post code in code or highlight tags and other useful info for new members.

    Please post your code correctly using code or highlight tags per the above link and post the complete error message with the stack trace.

    Posting multiple threads on the same topic is not to your benefit. Your duplicate threads have been deleted.

  3. The Following User Says Thank You to GregBrannon For This Useful Post:

    abuk10 (September 7th, 2014)

  4. #3
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    Default Re: Using method in Eclipse IDE

    THANK YOU FOR THE PROPER GUIDELINES..


    Hi, I would like to seek for help because right now I am very confused about why my code is not working..

    The function of my code will add records in my database (MySQL), Swing components of my frame..

    btnUserAdd = jButton
    txtUname, txtPword, txtLname, txtFname, txtMname, txtEmpNo = jTextField
    cbAccType = jComboBox
    EmpNo, Uname, Pword, Lname, Fname, Mname, AccType = MySQL fields

    I created a method to be called when btnUserAdd is clicked. here is the code for the method:

    public void UserAdd(){
     
    String sql = "SELECT * FROM User WHERE Uname = ? and EmpNo = ?";
     
         try {
     
              pst = conn.prepareStatement(sql);
              pst.setString(1, txtUname.getText().toString());
              pst.setString(2, txtEmpNo.getText().toString());
              rs = pst.executeQuery();
     
                   if (rs.next()){
     
                           JOptionPane.showMessageDialog(null, "Record Exists! Please Try Again.");
                           txtUname.requestFocus();
                           cbAccType.setSelectedItem("Operator");
                           UserClear();
     
                    }
                    else {
     
                            try {
     
                                   String sql1 = "INSERT INTO user (EmpNo, Uname, Pword, Lname, Fname, Mname, AccType)" + "VALUES (?, ?, ?, ?, ?, ?, ?)";
                                   String cb1 = cbAccType.getSelectedItem().toString();
     
                                   pst = conn.prepareStatement(sql1);
                                   pst.setString(1, txtEmpNo.getText());
                                   pst.setString(2, txtUname.getText());
                                   pst.setString(3, txtPword.getText());
                                   pst.setString(4, txtLname.getText());
                                   pst.setString(5, txtFname.getText());
                                   pst.setString(6, txtMname.getText());
                                   pst.setString(7, cb1);
                                   pst.execute();
     
                                   JOptionPane.showMessageDialog(null, "Record Added!");
     
                         }
                         catch (Exception e){
     
                                      JOptionPane.showMessageDialog(null, e);
     
                          }
     
                     }
     
          }
          catch (Exception e){
     
                      JOptionPane.showMessageDialog(null, e);
     
           }
     
    }

    then here is the code inside the btnUserAdd:

     
    btnUserAdd.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent evt) {
     
             if (txtUname.getText().trim().equals("")||txtPword.ge tText().trim().equals("")||txtEmpNo.getText().trim ().equals("")||txtLname.getText().trim().equals("" )){
     
                    JOptionPane.showMessageDialog(null, "Please Enter a Username, Password and Employee No, Try Again!");
     
                   if (txtUname.getText().trim().equals("")){
     
                          txtUname.requestFocus();
     
                   }
                  else if (txtPword.getText().trim().equals("")){
     
                          txtPword.requestFocus();
     
                   }
                  else if (txtLname.getText().trim().equals("")){
     
                          txtLname.requestFocus();
     
                   }
                  else if (txtEmpNo.getText().trim().equals("")){
     
                          txtEmpNo.requestFocus();
     
                   }
     
              }
              else{
     
                    UserAdd();	 //method for add
     
     
               }
     
    }
    });

    the problem is that it does not add the record it will display JAVA.LANG.NULLPOINTEREXCEPTION...

    please help me with my problem..

  5. #4
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    Default Re: Using method in Eclipse IDE

    Find the variable that is the nullpointer and then backtrack to find out why it is not properly initialized. Then decide how you would want to initialize it with a value properly.

  6. The Following User Says Thank You to Cornix For This Useful Post:

    abuk10 (September 7th, 2014)

  7. #5
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    Default Re: Using method in Eclipse IDE

    Quote Originally Posted by Cornix View Post
    Find the variable that is the nullpointer and then backtrack to find out why it is not properly initialized. Then decide how you would want to initialize it with a value properly.
    the catch is I call the method right? when I copy the code inside the method and paste it inside the actionperformed instead of calling the method, IT WORKS!! how is that working? thats my problem..

  8. #6
    Super Moderator Norm's Avatar
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    Default Re: Using method in Eclipse IDE

    how is that working?
    There can be many reasons. One for an NPE would be when the code is in one place a variable is still not initialized and when it is in another place, the variable has a valid value.

    You have to find what caused the error and fix it.
    If you don't understand my answer, don't ignore it, ask a question.

  9. The Following User Says Thank You to Norm For This Useful Post:

    abuk10 (September 7th, 2014)

  10. #7
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    Default Re: Using method in Eclipse IDE

    I will post if I fix this problem thanks by the way

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