Accessing Databases Using JDBC - Java Programming: Comprehensive Concepts and Techniques - page 734

23
24 try

25 {

26 Class .forName ( "sun.jdbc.odbc.JdbcOdbcDriver" ) ;

27 }

28 catch ( ClassNotFoundException ex )

29 {

30 throw new ClassNotFoundException ( ex.getMessage () +

31 "\nCannot locate sun.jdbc.odbc.JdbcOdbcDriver" ) ;

32 }

33
34 try

35 {

36 con = DriverManager .getConnection ( url ) ;

37 }

38 catch ( SQLException ex )

39 {

40 throw new SQLException ( ex.getMessage () +

41 "\nCannot open database connection for " +url ) ;

42 }

43 }

44 }

45
46 // Close makes database connection; null reference to connection

47 public void close () throws SQLException , IOException , ClassNotFoundException

48 {

49 con.close () ;

50 con = null ;

51 }

52
53 // Method to serialize object to byte array

54 private byte [] serializeObj ( Object obj ) throws IOException

55 {

56 ByteArrayOutputStream baOStream = new ByteArrayOutputStream () ;

57 ObjectOutputStream objOStream = new ObjectOutputStream ( baOStream ) ;

58
59

objOStream.writeObject ( obj ) ; // object must be Serializable

60 objOStream.flush () ;

61 objOStream.close () ;

62 return baOStream.toByteArray () ; // returns stream as byte array

63 }

64
65 // Method to deserialize bytes from a byte array into an object

66 private Object deserializeObj ( byte [] buf )

67 throws IOException , ClassNotFoundException

68 {

69 Object obj = null ;

70
71 if ( buf != null )

72 {

73 ObjectInputStream objIStream =

74 new ObjectInputStream ( new ByteArrayInputStream ( buf )) ;

75
76 obj = objIStream.readObject () ; //IOException, ClassNotFoundException

77 }

78 return obj;

79 }

80
81 ////////////////////////////////////////////////////////////////////////////

82 // Methods for adding a record to a table

83 ////////////////////////////////////////////////////////////////////////////

84 // add to the Stocks Table

85 public void addStock ( String stockSymbol, String stockDesc )

86 throws SQLException , IOException , ClassNotFoundException

87 {

88 Statement stmt = con.createStatement () ;

89 stmt.executeUpdate ( "INSERT INTO Stocks VALUES ('"

90 +stockSymbol+ "'"

91 + ",'" +stockDesc+ "')" ) ;

92 stmt.close () ;

93 }

94

FIGURE 11-36