[求助]SQLException: ResultSet is closed

public ResultSet getBookList(){    
    PreparedStatement ptmt = null;
    Connection con = getDBConnection();//我寫的連線方法  
   try{  
       ptmt = con.prepareStatement("select * from bookInfo");
       System.out.println ("可以執行到這裡");
       return ptmt.executeQuery();
   
      }catch(SQLException e){
           e.printStackTrace();
           return null;
            
      }finally{
         try{
               ptmt.close();
               con.close();    
            }catch(SQLException e){
               e.printStackTrace();
            }
     }    
}
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