public class FileClassDemo
1:
2: /**
3: Demonstrates use of the class File with text files.
4: */
5: import java.io.*;
6: import java.util.*;
7:
8: public class FileClassDemo
9: {
10: public static void main(String[] args)
11: {
12: String name = null;
13: System.out.println("I will show you the first line");
14: System.out.println("in a text file you name.");
15: System.out.println("The file must contain one or more lines.");
16: System.out.println("Enter file name:");
17: Scanner keyboard = new Scanner(System.in);
18:
19: name = keyboard.next( );
20: File fileObject = new File(name);
21:
22: while (( ! fileObject.exists( ))
23: || ( ! fileObject.canRead( )))
24: {
25: if ( ! fileObject.exists( ))
26: System.out.println("No such file");
27: else // ! fileObject.canRead( )
28: System.out.println("That file is not readable.");
29: System.out.println("Enter file name again:");
30: name = keyboard.next( );
31: fileObject = new File(name);
32: }
33:
34: try
35: {
36: BufferedReader fileInput =
37: new BufferedReader(new FileReader(name));
38: System.out.println("The first line in the file is:");
39: String firstLine = fileInput.readLine( );
40: System.out.println(firstLine);
41: fileInput.close( );
42: }
43: catch(IOException e)
44: {
45: System.out.println("Problem reading from file.");
46: }
47: }
48: }