Java How to Program Fourth Edition - DCC

932 Files and Streams Chapter 16
25
26 // if user clicked Cancel button on dialog, return
27 if ( result == JFileChooser.CANCEL_OPTION )
28 return;
29
30 // obtain selected file
31 File fileName = fileChooser.getSelectedFile();
32
33 // display error if file name invalid
34 if ( fileName == null ||
35 fileName.getName().equals( "" ) )
36 JOptionPane.showMessageDialog( null,
37 "Invalid File Name", "Invalid File Name",
38 JOptionPane.ERROR_MESSAGE );
39
40 else {
41
42 // open file
43 try {
44 RandomAccessFile file =
45 new RandomAccessFile( fileName, "rw" );
46
47 RandomAccessAccountRecord blankRecord =
48 new RandomAccessAccountRecord();
49
50 // write 100 blank records
51 for ( int count = 0; count < 100; count++ )
52 blankRecord.write( file );
53
54 // close file
55 file.close();
56
57 // display message that file was created
58 JOptionPane.showMessageDialog( null,
59 "Created file " + fileName, "Status",
60 JOptionPane.INFORMATION_MESSAGE );
61
62 System.exit( 0 ); // terminate program
63 }
64
65 // process exceptions during open, write or
66 // close file operations
67 catch ( IOException ioException ) {
68 JOptionPane.showMessageDialog( null,
69 "Error processing file", "Error processing file",
70 JOptionPane.ERROR_MESSAGE );
71
72 System.exit( 1 );
73 }
74 }
75
76 } // end method openFile
77
Fig. Fig. 16.12 16.12 Creating a random-access file sequentially (part 2 of 3).