Call bean, consult experts Below are two bean bag in the data, a database linked to the implementation of the translation would not be a problem, The second is to use a bean for the completion of the actual database connection data exchange methods, but always mistakes in the translation error to help look for the following : Which error debugging help, be grateful! ! ! [color=red]viewdata.java:18 Can not resolve symbol : Symbol : 14.00 Dbcon Location data package : Data.Dbcon dc=null;       ^ Viewdata.java:22 can not resolve symbol : Symbol : 14.00 Dbcon Location : 14.00 data.ViewData Dc=new Dbcon ();            ^ 2 errors [/color]_____________________________________________---- [color=green][color=red]Dbcon.java ________________________________________________---- [/color][/color] Package data; Import java.lang.*; Import java.util.*; Import java.sql.*; Import java.io.*; /**gffsgfsfgffgs * "P>;Title :" /p>; * "P>;Description :" /p>; * "P>;Copyright : Copyright (c) 2003</p>; * "P>;Company :" /p>; *author Not attributable *version 1.0 */ Public class Dbcon{ Public Connection conn = null; Public Statement stmt = null; Public ResultSet rset = null; Public Dbcon () (   } Public boolean openCon () ( String jdbc = "com.mysql.jdbc.Driver"; String government payments are capped = "jdbc:mysql://localhost:3306/counter"; String user= "aaaaa"; String password = "aaaaa"; //--step 3 //-- Strategy //--step Driven four loading jdbcjdbc //-- Strategy Try ( Class.forName (jdbc);     } Catch (ClassNotFoundException e) ( System.out.println ( "jdbc invasion mistakes" + e.getMessage ()); Return false;     } //step5. Open database con Try ( This.conn = DriverManager.getConnection (government payments are capped, user, password);     } Catch (SQLException e) ( System.out.println ( "Generation connection error :" + e.getMessage ()); Return false;     } Return true;   }   /*********** * ExecuteQuery method name : * Query parameters : (sgl words) * Java.sql.ResultSet return value type :    * **********    */ Public ResultSet executeQuery (String query) throws SQLException -- This.stmt = conn.createStatement (ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE); This.rset = stmt.executeQuery (query); Return rset;   }   /********* * Name : executeUpdate method * Parameters : qufery (sgl words) * Void return type : * Note : The revised method of data * (UPDATE, Base DELETE, and INSERT)    */ Public void executeUpdate (String query) throws SQLException   { This.stmt = conn.createStatement (java.sql.ResultSet.TYPE_SCROLL_SENSITIVE, java.sql.ResultSet.CONCUR_UPDATABLE); Stmt.executeUpdate (query); If (stmt!=null) stmt.close ();         }         /******** * Name : close approach * Parameters : None * Void return value :          */ Public void close () throws SQLException      { If (conn!=null) conn.close (); If (rset!=null) rset.close (); If (stmt!=null) stmt.close ();      }      /****** * Name : finalize method * Parameters : None * Void return value type :             */ Protected void finalize () throws Throwable{ This.close ();               } } _____________________________ [color=red]Viewdata.java ________________________------ [/color] Package data; Import java.lang.*; Import java.util.*; Import java.sql.*; Import java.io.*; /** * "P>;Title :" /p>; * "P>;Description :" /p>; * "P>;Copyright : Copyright (c) 2003</p>; * "P>;Company :" /p>; *author Not attributable *version 1.0 */ Public class ViewData{ Data.Dbcon dc=null; ResultSet rset=null; Public ViewData ()   { Dc=new data.Dbcon ();   } //*** Generation connection   //**** Public boolean openCon ()    { Return dc.openCon ();         } //*** Implementation sgl (insert) / Public void executeQuery (String query) throws SQLException     { This.rset =dc.executeQuery (query);     } //*** Implementation sgl (update, delete. . . . ) / Public void excuteUpdate (String query) throws SQLException       { Dc.executeUpdate (query);       } //*** Get all column./ Public int getColumnCount () throws SQLException       { ResultSetMetaData rsmd =rset.getMetaData (); Return rsmd.getColumnCount ();       } Column numbers obtained by searching the name //*** / Public String getColumnName (int index) throws SQLException       { ResultSetMetaData rsmd =rset.getMetaData (); Return rsmd.getColumnName (ENH);       } //*** Through the column index data acquisition / Public String getData (int index) throws SQLException        { Return rset.getString (ENH). Trim ();        } //*** Column by the name of data acquisition /        //***************************** Public String getData (String columnName) throws SQLException         { Return rset.getString (columnName). Trim ();         } //*** Will scale down resultset record /*******************/ Public boolean next () throws SQLException         { Return rset.next ();         } //***close          /********           *           */ Public void close () throws SQLException          { If (rset!=null) rset.close (); If (dc!=null) dc.close ();          } //*******finalize ()          // ?*********/ Protected void finalize () throws Throwable         { Close ();         } } Call bean, consult experts Changed Dbcon dc=null; try, try to name a packet [ Closed window ]