问javafx - log in函数如果log in详细信息正确，则执行'else‘块，但当详细信息错误时，什么也不会发生

EN

public class Log_inController implements Initializable {
private DBConnection dc;

@FXML TextField txtUn;
@FXML PasswordField txtPw;
@FXML Button btnLogin;


@Override
public void initialize(URL url, ResourceBundle rb) {
    // TODO
}    


@FXML
public void log_in (ActionEvent event) throws SQLException, IOException {
     dc = new DBConnection();
   try{
        String name =  txtUn.getText();
        String pass =  txtPw.getText();
        
        
        Connection conn = dc.Connect();
        ResultSet rs = conn.createStatement().executeQuery("SELECT * FROM tbl_lib WHERE lib_acc = '"+ name +"'");
   
    
    if(rs.next()){
        String database_name = rs.getString(1);
        String database_pass = rs.getString(2); 
        
        if(name.equals(database_name) && pass.equals(database_pass)){
            Parent x=FXMLLoader.load(getClass().getResource("/Collection_UI/Home.fxml")); 
            Scene  M= new Scene(x);
            Stage app=(Stage)((Node)event.getSource()).getScene().getWindow();
            app.setScene (M);
            app.show();
        }else{
            Alert alert = new Alert(AlertType.WARNING);
            alert.setHeaderText("Invalid Credentials");
            alert.setContentText("Please input your valid username and password then try again");

            alert.showAndWait();  
        }
   }
    
}
 catch(SQLException ex){
     System.err.println("Error"+ex);
 }
         
         }
    
}