String.length（）给我一个错误的值

Question

Whenever I enter a password under 10 characters it gives me Password cannot exceed 10 characters .

private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        String name = Name.getText();
        String Username = uName.getText().toString();
        String Pass1 = uPass.getPassword().toString();
        String Confirm = uConfirm.getPassword().toString();
        String Status = "OFFLINE";
        int PassLen = Pass1.length();

        if (Username.equals("") || Pass1.equals("") || Confirm.equals("") || name.equals("")) 
        {
            JOptionPane.showMessageDialog(null, "You cannot leave any fields blank when creating an Account. Please Try Again");
        } 
        else if ((uPass.getPassword().toString()).length()>10)
        {
            uPass.setText("");
            uConfirm.setText("");
            JOptionPane.showMessageDialog(null, "Password cannot exceed a maximum of 10 characters.");  
        }
        else if (!Pass1.equals(Confirm))
        {
            uConfirm.setText("");
            lblError1.setText("Passwords Do Not Match.");
            lblError2.setText("Please re-enter your Password.");
        }
        else
        {
            try {
                DB_Connect connect = new DB_Connect();
                ResultSet rs = connect.queryTbl("SELECT * FROM ACOUNTS");
                boolean AlreadyUser = false;
                String User;
                while (rs.next())
                {
                    User = rs.getString("Username");
                    if(Username.equals(User))
                    {
                        AlreadyUser = true;
                    }
                }
                if (AlreadyUser==false)
                {
                    connect.updateTbl("INSERT INTO NBUSER.ACCOUNTS (USERNAME,PASSWORD,STATUS,NAME)VALUES ('"+Username+"','"+Pass1+"','"+Status+"','"+name+"')");
                    JOptionPane.showMessageDialog(null, "Account Created Successfully !");
                    this.dispose();
                    new Topics().setVisible(true);
                }
                else
                {
                    JOptionPane.showMessageDialog(null, "The Username you have selected already exists. Please select a different Username");
                    uPass.setText("");
                    uConfirm.setText("");
                }
            } catch (SQLException ex) {
                Logger.getLogger(CreateAccount.class.getName()).log(Level.SEVERE, null, ex);
            }

        }


    }                                        

Answer 1

Since you're obviously using Swing, it is also very likely that you use a JPasswordField for your passwords. So let's see, what getPassword really does:

public char[] getPassword()

Returns the text contained in this TextComponent. If the underlying document is null, will give a NullPointerException. For stronger security, it is recommended that the returned character array be cleared after use by setting each character to zero.

Returns: the text

As you can see, it returns your password in a char[] and since this class doesn't override toString your call of uPass.getPassword().toString() results in something like:

[C@1d44bcfa

which is the result of calling Object#toString .

The length of this String is 11 and therefore larger then 10 and your else if block ( else if ((uPass.getPassword().toString()).length()>10) ) will be entered.

To fix that, call the String constructor String(char[]) like:

String Pass1 = new String(uPass.getPassword());

---

Please use this just as a "quick fix" for your current problem and try to find a way to use the originally returned char[] . As mentioned by the quoted JavaDoc it is recommened the "clean" the char array after using it, so the password won't be stored there anymore. By creating a String from the array, using new String(uPass.getPassword()) , you're creating another object in the heap which contains the password and which also needs to be removed from there. So it would add more work for you.