无法匹配用户和通过登录表单netbeans

Question

如何在以下条件下匹配用户和密码。我总是得到用户名/密码不匹配。

try
{
    Conn();
    st = conn.createStatement();
    rs = st.executeQuery("Select UserName,PassWord from login_tbl where UserName = '"+txtUser.getText()+"' and PassWord = '"+txtPass.getPassword()+"'");
    if(rs != null)
    {
        new CarRent().setVisible(true);
        this.dispose();
    }
    else
    {
        JOptionPane.showMessageDialog(null, "Your Username or Password is incorrect","",JOptionPane.ERROR_MESSAGE);
    }
}

Answer 1

您应该使用这个rs.next()而不是这个rs != null

try
        {
            JOptionPane.showMessageDialog(null, "Username is : " + txtUser.getText().trim().toString() + " Password is : " + txtPass.getPassword().trim().toString(),"",JOptionPane.ERROR_MESSAGE);
        Conn();
        st = conn.createStatement();
        rs = st.executeQuery("Select UserName,PassWord from login_tbl where UserName = '"+txtUser.getText()+"' and PassWord = '"+txtPass.getPassword()+"'");

        if(rs.next())
        {
            JOptionPane.showMessageDialog(null, "Password is valid","",JOptionPane.ERROR_MESSAGE);
            new CarRent().setVisible(true);
            this.dispose();
         }
        else
        {
            JOptionPane.showMessageDialog(null, "Your Username or Password is incorrect","",JOptionPane.ERROR_MESSAGE);
        }

Answer 2

感谢大家，我已经解决了我的问题:)

String sql = "select * from login_tbl where usern=? and pass=?";
   try{
       Conn();
   ps=conn.prepareStatement(sql);
   ps.setString(1,txtUser.getText());
   ps.setString(2,new String(txtPass.getText()));
   rs=ps.executeQuery();
   if (rs.next()){
       //about s= new about();
       //
       //s.setVisible(true);
       new CarRent().setVisible(true);
       dispose();
      }
   else
   {
       JOptionPane.showMessageDialog(null, "Password or Username is incorrect");
   }
   }
   catch(Exception e)
   {
        JOptionPane.showMessageDialog(null, e);
   }